The electronic engine control unit for Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines of Toyota Corolla, Corona, Toyota Carina E, Caribbean, Toyota Celica, Sprinter, Kaldina is programmed to provide optimal angle ignition timing at various engine operating modes.
Using information about the operating conditions of the engine (speed, coolant temperature, etc.), the microcomputer issues the command to deliver a spark discharge exactly at the right moment in the engine's operating cycle.
Fig. 38. The layout of the elements of the ignition system on a car with a 4A-FE engine (AT190)
1 - 2.0L main fuse, 2 - spark plugs, 3 - electronic control unit (for left-hand models steering), 4 - integrated ignition unit, 5 - diagnostic connector, 6 - electronic control unit (for models with right-hand drive), 7 - AM2 fuse link (30 A).
The electronic engine control unit for Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE cars Toyota Corolla, Corona, Toyota Carina E, Carib, Toyota Celica, Sprinter, Kaldina monitors its operating conditions using signals from the appropriate sensors.
Based on these signals, the electronic control unit calculates the required ignition timing and sends a control signal to the switch. The high voltage is distributed across the spark plugs in accordance with the engine's operating order and causes a spark discharge between the spark plug electrodes, which ignites the air / fuel mixture.
The joint unit (block) of ignition of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines of Toyota Corolla, Corona, Toyota Carina E, Carib, Toyota Celica, Sprinter, Kaldina (contactless ignition system unit) includes : switch, ignition coil, spark discharge distributor for engine cylinders, as well as rotors and inductive coils of the crankshaft angle sensor and the camshaft angle sensor.
The switch intermittently interrupts the primary current from the ECM (IGT signal), thereby creating a spark across the spark plugs. In addition, in order to increase the reliability of the ignition system, at the time of sparking, information about this (IGF signal) is sent to the electronic engine control unit.
The ignition coil consists of a closed core, a primary winding that encloses the core, and a secondary winding that encloses the primary winding. This design creates a high voltage that can cause a powerful spark discharge in the gap between the spark plug electrodes.
The ignition distributor distributes the high voltage to the spark plugs of each cylinder in accordance with the engine running order. Inductive coil "NE" with a magnetoelectric pulse generator allows to determine the angular position of the crankshaft, and inductive coil "G" - the angular position of the camshaft, which is necessary for the correct determination of the ignition moment.
Note: on some engines, for example, 4A-GE (version without air mass meter) or 4A-FE (version with lean combustion system), two inductive coils "G1" and "G2" are used on the camshaft angle sensors.
Warnings for the ignition system in the operation of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines:
Do not leave the ignition on for more than 10 minutes if the engine is not running.
When connecting the tachometer to the ignition system, connect the tachometer working wire to the IG (-) terminal of the diagnostic connector of the integrated electronic ignition unit, and the power wires to the battery.
Since not all tachometers are compatible with this ignition system, make sure they are compatible before using the tachometer.
Never allow the output contacts of the tachometer to touch "ground": this leads to failure of the commutator and / or the ignition coil of the engine under test.
Do not disconnect the battery while the engine is running.
Make sure the switch is securely connected to vehicle ground.
Fig. 39. Ignition system diagram 4A-FE and 7A-FE (AE102)
1 - battery, 2 - main fuse-link (3.0W for AE or 2.0L for AT), 3 - AM2 fuse-link (30 A), 4 - ignition switch, 5 - spark plugs, 6 - integrated ignition unit, 7 - rotor and ignition distributor cover, 8 - capacitor, 9 and 10- rotor and inductive winding of the crankshaft angular position sensor, 11 and 12- rotor and inductive winding of the camshaft angular position sensor, 13 - ignition coil, 14 - switch, 15 - diagnostic connector of the switch, 16 - electronic control unit.
Fig. 40. 4A-GE ignition system diagram without air mass meter)
1 - rechargeable battery, 2 - AM2 fusible link (30 A), 3 - ignition switch, 4 - spark plugs, 5 - rotor and ignition distributor cover, 6 - ignition coil, 7 - switch, 8 - to the tachometer, 9 and 10 - rotor and inductive winding of the crankshaft angular position sensor, 11 and 12 - rotor and inductive windings of the camshaft angular position sensor, 13 - electronic control unit.
Spark test (For all motors except 4A-GE)
Disconnect the high voltage wires from the spark plugs.
Remove spark plugs and reconnect high voltage wires.
Ground (ground) the spark plug housings.
Be sure to generate sparks on each spark plug when cranking the engine with the starter motor. (Only for 4A-GE and 4A-FE with lean burn system)
Disconnect the high voltage wires from the distributor.
Keeping the ends of the wires at a distance of 12.5 mm from the "ground" (car body), make sure there is sparking when cranking the engine with the starter. Attention: to prevent a significant amount of fuel from entering the cylinders from the working injectors, the test should be carried out for no more than 1-2 s. If sparking is not observed, it is necessary to check in the following
sequence.
The terms "cold" and "hot" windings of an ignition coil or angle encoder coil in the following sentences refer to the temperature of the windings:
- "cold" from -10 ° С to + 50 ° С
- "hot" from + 50 ° С to + 100 ° С
Check the connections in the integrated ignition unit: ignition coil, switch, distributor connectors.
Check the resistance of the high voltage wires. Maximum resistance of each wire 25 kOhm
Check for voltage at the positive (+) terminal of the ignition coil with the ignition on.
Check the resistance of the ignition coil windings according to the appropriate table.
Check the resistance of the winding of the inductive coil of the crankshaft angle sensor (terminals NE (+) and NE (-)) and the camshaft angle sensor (terminals G (+) and G (-)) according to the corresponding table.
If the resistance does not correspond to the technical data, then:
ICE 4A-FE (AE101 and AT190), 4A-GE and 5A-FE (AE110) - Replace the valve body assembly.
ICE 4A-FE (except for АЕ101 and АТ190) - Replace the complex (combined) ignition unit (contactless ignition system unit).
Check the air gap of the distributor. Gap size 0.2 - 0.4 mm
If the clearance does not match the technical data, then replace:
Engine 4A-FE (AE101 and AT190), 4A-GE, SAFE (AE110), 7A-FE (AE93, AE102)) - Distributor housing assembly.
4A-FE engine (except АЕ101 and АТ190) - Integrated ignition unit.
Check for a control signal from the ECM.
Check the condition of the wiring from the computer to the integrated ignition assembly. Replace the electronic control unit if necessary.
Try using a different switch.
Checking high-voltage wires of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines of Toyota Corolla, Corona, Toyota Carina E, Carib, Toyota Celica, Sprinter, Kaldina
Disconnect the high voltage wires from the spark plugs by holding only the rubber caps. Improper handling of wires can cause internal wire breaks.
Except 7A-FE and 4A-GE - Disconnect the high voltage wires from the distributor cover or from the ignition assembly cover. To do this, use a screwdriver to pull back the spring latch and disconnect the holder together with the high-voltage wire from the distributor cover.
Using an ohmmeter, check the resistance of each high voltage wire.
For 7A-FE and 4A-GE engines, the wire resistance is checked together with the distributor cover or the electronic ignition module. Maximum resistance ... 25 kOhm per wire. If the resistance is greater than the specified value, check the wire lugs or replace the wires.
Except for 7A-FE and 4A-GE - Connect the high voltage wires to the distributor cap or the ignition assembly.
Connect high voltage wires to spark plugs, paying attention to wire routing and clamping.
Checking spark plugs for Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines
Disconnect the high voltage wires from the spark plugs.
Remove the spark plugs using a 16mm spark plug wrench.
Clean spark plugs with a sandblaster or wire brush.
Visually check the condition of the spark plugs for worn electrodes, damaged threads and / or insulator. Replace spark plug if necessary.
Adjust the electrode gap by bending only the side electrode.
Checking the ignition system elements or elements of the joint ignition unit of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines of Toyota Corolla, Corona, Toyota Carina E, Carib, Toyota Celica, Sprinter, Kaldina
In the 4A-GE engine and in the 4A-FE engine (with a lean-burn combustion system), there is no combined ignition unit, but the procedures for checking the elements of the ignition system of the same name (ignition coils, distributor-distributor, commutator, angular impulse sensors, etc.) are similar the procedures for checking these elements in the combined ignition unit and are considered in parallel.
For ignition systems with a composite ignition unit - Disconnect the connectors of the integrated ignition unit, remove the distributor cap and rotor, and the ignition coil boot.
For engine ignition systems with a distributor - Disconnect the ignition coil connector and disconnect the high voltage wire from the ignition coil.
Checking the ignition coil of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines
Note: The terms "cold" and "hot" ignition coil windings in the following sentences refer to the temperature of the windings:
- "Cold" from -10ОС to + 50ОС
- "Hot" from + 50 ° C to + 100 ° C
These definitions are further retained for the inductive coils of angle-pulse transmitters.
Check the resistance of the primary winding using an ohmmeter connected to the ignition coil.
Check the resistance of the secondary winding using an ohmmeter connected to the ignition coil. If the resistance of any of the windings of the ignition coil is not within the rated value, replace the ignition coil.
For 4A-FE with a lean burn system - Using a megohmmeter, measure the insulation resistance between the positive (+) terminal of the ignition coil and the terminal (terminal) of the high voltage wire. The nominal resistance value is at least 10 megohms. Otherwise, replace the ignition coil.
For 4A-FE with a lean burn system - Connect the high voltage wire to the ignition coil as well as the ignition coil connector.
Checking the supply voltage of the integrated ignition unit (4A-FE (AE111), 7A-FE (AE115), 5A-FE (AE110)
Disconnect the ignition sub-assembly connector and measure the voltage between the "1" terminal of the assembly connector and ground by turning the ignition key to the "ON" and "START" positions. Supply voltage ..... 9 -14 V
Checking the distributor-distributor of ignition of Toyota 4A-FE, 5A-FE, 4A-GE, 7A-FE engines
Disconnect the distributor connector, remove the distributor cap and spark distributor rotor.
Check with a feeler gauge the air gap between the rotor teeth of the angle encoder and the protrusion of the inductive coil of the angle encoder. If the ignition system uses two angle encoders (crankshaft angle sensor "NE" and camshaft angle sensor "G1"), then similar measurements must be made in each sensor.
In 4A-GE engines without an air mass meter, these measurements must be performed three times: in the crankshaft angle sensor "NE" and two camshaft angle sensors "GT and G2" Nominal air gap 0.2 - 0.4 mm. If the clearance is outside the specified limits, replace the distributor housing, distributor assembly, or ignition interconnection housing.
Check with an ohmmeter the resistance of the inductive coils of the crankshaft and camshaft position sensors.
____________________________________________________________________________
Reliable japanese engines
04.04.2008
The most widespread and by far the most widely repaired Japanese engine is the Toyota 4, 5, 7 A - FE engine. Even a novice mechanic, diagnostician knows about possible problems engines of this series.
I will try to highlight (put together) the problems of these engines. There are few of them, but they cause a lot of trouble to their owners.
Date from scanner:
On the scanner, you can see a short but capacious date, consisting of 16 parameters, by which you can realistically evaluate the operation of the main engine sensors.
Sensors:
Oxygen sensor - Lambda probe
Many owners turn to diagnostics due to increased fuel consumption. One of the reasons is a banal break in the heater in the oxygen sensor. The error is recorded by the code control unit number 21.
The heater can be checked with a conventional tester on the sensor contacts (R- 14 Ohm)
Fuel consumption increases due to the lack of correction during warming up. You will not be able to restore the heater - only replacement will help. The cost of a new sensor is high, but it does not make sense to install a used one (the resource of their operating time is large, so this is a lottery). In such a situation, the less reliable NTK universal sensors can be installed as an alternative.
Their service life is short, and the quality is poor, so such a replacement is a temporary measure, and it should be done with caution.
With a decrease in the sensitivity of the sensor, an increase in fuel consumption occurs (by 1-3 liters). The performance of the sensor is checked with an oscilloscope on the diagnostic connector block, or directly on the sensor chip (number of switchings).
temperature sensor
If not correct work the owner's sensor will face a lot of problems. In the event of a break in the measuring element of the sensor, the control unit replaces the sensor readings and fixes its value at 80 degrees and fixes error 22. The engine, with such a malfunction, will operate normally, but only while the engine is warm. Once the engine has cooled down, it will be problematic to start it without doping, due to the short opening time of the injectors.
It is not uncommon for the resistance of the sensor to change chaotically when the engine is running on H.H. - the revolutions will float.
This defect can be easily fixed on the scanner by observing the temperature reading. On a warm engine, it should be stable and not change randomly from 20 to 100 degrees.
With such a defect in the sensor, "black exhaust" is possible, unstable operation on Х.Х. and, as a consequence, increased consumption, as well as the impossibility of starting "hot". Only after 10 minutes of rest. If there is no complete confidence in the correct operation of the sensor, its readings can be substituted by including a variable resistor of 1kΩ, or a constant 300Ω in its circuit, for further verification. By changing the sensor readings, it is easy to control the change in speed at different temperatures.
Position sensor throttle
A lot of cars go through the disassembly assembly procedure. These are the so-called "constructors". When removing the engine in field conditions and subsequent assembly, sensors suffer, on which the engine is often leaned against. If the TPS sensor breaks, the engine stops throttling normally. The engine chokes when accelerating. The machine switches incorrectly. The control unit fixes error 41. When replacing a new sensor, it must be configured so that the control unit correctly sees the X.X sign when the gas pedal is fully released (throttle valve closed). In the absence of a sign of idling, adequate regulation of the Х.Х will not be carried out. and there will be no forced idling during engine braking, which again will entail increased fuel consumption. On engines 4A, 7A, the sensor does not require adjustment, it is installed without the possibility of rotation.
THROTTLE POSITION …… 0%
IDLE SIGNAL ……………… .ON
Sensor absolute pressure MAP
This sensor is the most reliable of all installed on Japanese cars. Its reliability is simply amazing. But it also has a lot of problems, mainly due to improper assembly.
Either the receiving "nipple" is broken, and then any passage of air is sealed with glue, or the tightness of the supply tube is violated.
With such a rupture, fuel consumption increases, the level of CO in the exhaust rises up to 3%. It is very easy to observe the operation of the sensor using a scanner. The line INTAKE MANIFOLD shows the vacuum in the intake manifold, which is measured by the MAP sensor. If the wiring is broken, the ECU registers error 31. At the same time, the opening time of the injectors sharply increases to 3.5-5 ms. During gas re-gasings, a black exhaust appears, the candles are planted, there is a shaking on the X.X. and stopping the engine.
Knock sensor
The sensor is installed to register detonation knocks (explosions) and indirectly serves as a "corrector" for the ignition timing. The recording element of the sensor is a piezoplate. In the event of a sensor malfunction, or a break in the wiring, at overgasings of more than 3.5-4 tons. The ECU registers an error 52.
You can check the performance with an oscilloscope, or by measuring the resistance between the sensor terminal and the case (if there is resistance, the sensor needs to be replaced).
Crankshaft sensor
A crankshaft sensor is installed on the 7A series engines. A conventional inductive sensor, similar to the ABC sensor, is practically trouble-free in operation. But embarrassment also happens. With a turn-to-turn closure inside the winding, the generation of pulses is disrupted at certain speeds. This manifests itself as a limitation of engine speed in the range of 3.5-4 t. Revolutions. A kind of cutoff, only at low revs. It is quite difficult to detect an interturn short circuit. The oscilloscope does not show a decrease in the amplitude of pulses or a change in frequency (with acceleration), and it is rather difficult to notice changes in Ohm fractions with a tester. If you experience symptoms of speed limitation at 3-4 thousand, just replace the sensor with a known good one. In addition, a lot of trouble is caused by damage to the driving ring, which is damaged by careless mechanics when they replace the front crankshaft oil seal or timing belt. Having broken the teeth of the crown, and restoring them by welding, they achieve only a visible absence of damage.
At the same time, the crankshaft position sensor ceases to adequately read information, the ignition timing begins to change chaotically, which leads to a loss of power, unstable engine operation and an increase in fuel consumption
Injectors (nozzles)
During many years of operation, the nozzles and needles of the injectors are covered with resins and gasoline dust. All this naturally interferes with the correct spray pattern and reduces the performance of the nozzle. In case of heavy pollution, noticeable shaking of the engine is observed, and fuel consumption increases. It is realistic to determine the clogging by conducting a gas analysis, according to the oxygen readings in the exhaust, it is possible to judge the correctness of the filling. A reading greater than one percent will indicate the need to flush the injectors (if correct installation Timing and normal fuel pressure).
Or by installing the injectors on the bench and checking the performance in tests. The nozzles are easy to clean with Laurel, Vince, both in CIP installations and in ultrasound.
The valve is responsible for the engine speed in all modes (warm-up, idle, load). During operation, the valve petal becomes dirty and the stem wedges. The revolutions freeze on heating or on H.H. (due to a wedge). Tests for changing the speed in scanners during diagnostics for this motor are not provided. You can evaluate the valve's performance by changing the readings of the temperature sensor. Put the engine in "cold" mode. Or, removing the winding from the valve, twist the valve magnet with your hands. Sticking and wedge will be felt immediately. If it is impossible to easily dismantle the valve winding (for example, on the GE series), you can check its operability by connecting to one of the control outputs and measuring the duty cycle of the pulses while simultaneously monitoring the H.X. speed. and changing the load on the engine. On a fully warmed-up engine, the duty cycle is approximately 40%, changing the load (including electrical consumers), it is possible to estimate an adequate increase in speed in response to a change in the duty cycle. With mechanical jamming of the valve, there is a smooth increase in the duty cycle, which does not entail a change in the speed of H.H.
You can restore work by cleaning carbon deposits and dirt with a carburetor cleaner with the winding removed.
Further adjustment of the valve is to set the H.H. speed. On a fully warmed up engine, by rotating the winding on the mounting bolts, tabular revolutions are achieved for this type of car (according to the tag on the hood). By pre-installing jumper E1-TE1 in the diagnostic block. On the "younger" motors 4A, 7A, the valve was changed. Instead of the usual two windings, a microcircuit was installed in the body of the valve winding. Changed the valve power and the color of the winding plastic (black). It is already pointless to measure the resistance of the windings at the terminals on it.
The valve is supplied with power and a control signal rectangular variable duty cycle.
For the impossibility of removing the winding, non-standard fasteners were installed. But the wedge problem remained. Now if you clean it with an ordinary cleaner, the grease is washed out from the bearings (the further result is predictable, the same wedge, but due to the bearing). It is necessary to completely dismantle the valve from the throttle body and then carefully flush the stem with a petal.
Ignition system. Candles.
A very large percentage of cars come to the service with problems in the ignition system. When operating on low-quality gasoline, spark plugs are the first to suffer. They are covered with a red coating (ferrosis). There will be no high-quality sparking with such candles. The engine will run intermittently, with gaps, fuel consumption increases, the level of CO in the exhaust rises. Sandblasting cannot clean such candles. Only chemistry (silite for a couple of hours) or replacement will help. Another problem is the increase in clearance (simple wear).
Drying of the rubber tips of high-voltage wires, water that got in during the washing of the motor, which all provoke the formation of a conductive track on the rubber tips.
Because of them, sparking will not be inside the cylinder, but outside it.
With smooth throttling, the engine runs stably, and with sharp throttling, it “crushes”.
In this position, it is necessary to replace both candles and wires at the same time. But sometimes (in the field), if replacement is impossible, you can solve the problem an ordinary knife and a piece of emery stone (fine fraction). With a knife we cut off the conductive path in the wire, and with a stone we remove the strip from the ceramic of the candle.
It should be noted that it is impossible to remove the rubber band from the wire, this will lead to the complete inoperability of the cylinder.
Another problem is related to the incorrect procedure for replacing the plugs. The wires are forcibly pulled out of the wells, tearing off the metal tip of the rein.
With such a wire, misfiring and floating revolutions are observed. When diagnosing the ignition system, always check the performance of the ignition coil on the high-voltage arrester. The simplest check is to look at the spark on the spark gap while the engine is running.
If the spark disappears or becomes threadlike, this indicates an interturn short circuit in the coil or a problem in the high-voltage wires. Wire breakage is checked with a resistance tester. Small wire 2-3kom, further to increase the long 10-12kom.
The resistance of a closed coil can also be checked with a tester. The secondary resistance of the broken coil will be less than 12kΩ.
The next generation coils do not suffer from such ailments (4A.7A), their failure is minimal. Proper cooling and wire thickness eliminated this problem.
Another problem is the leaking oil seal in the distributor. Oil on the sensors corrodes the insulation. And when exposed to high voltage, the slider is oxidized (covered with a green coating). The coal turns sour. All this leads to the disruption of sparking.
In motion, chaotic lumbago is observed (into the intake manifold, into the muffler) and crushing.
" Thin " malfunctions Toyota engine
On modern Toyota 4A, 7A engines, the Japanese changed the firmware of the control unit (apparently for faster engine warm-up). The change lies in the fact that the engine reaches H.H. rpm only at a temperature of 85 degrees. The design of the engine cooling system has also been changed. Now the small cooling circle passes intensively through the block head (not through the branch pipe behind the engine, as it was before). Of course, the cooling of the head has become more efficient, and the engine as a whole has become more efficient. But in winter, with such cooling when driving, the engine temperature reaches a temperature of 75-80 degrees. And as a result, constant warming up revolutions (1100-1300), increased fuel consumption and anxiety of the owners. You can deal with this problem either by insulating the engine more strongly, or by changing the resistance of the temperature sensor (by deceiving the ECU).
Butter
Owners pour oil into the engine indiscriminately, without thinking about the consequences. Few people understand that different types oils are incompatible and, when mixed, form an insoluble slurry (coke), which leads to the complete destruction of the engine.
All this plasticine cannot be washed off with chemistry, it can only be cleaned mechanically... It should be understood that if you do not know what type of old oil, then you should use flushing before changing. And more advice to the owners. Pay attention to the color of the dipstick handle. He yellow color... If the color of the oil in your engine is darker than the color of the handle, then it's time to make a change, and not wait for the virtual mileage recommended by the engine oil manufacturer.
Air filter
The most inexpensive and readily available element is the air filter. Owners very often forget about replacing it, without thinking about the likely increase in fuel consumption. Often, due to a clogged filter, the combustion chamber is very heavily contaminated with burned oil deposits, valves and candles are heavily contaminated.
When diagnosing, it can be mistakenly assumed that the wear of the valve stem seals is to blame, but the root cause is a clogged air filter, which increases the vacuum in the intake manifold when contaminated. Of course, in this case, the caps will also have to be changed.
Some owners do not even notice about living in the building air filter garage rodents. Which speaks of their utter disregard for the car.
Fuel filteralso deserves attention. If it is not replaced in time (15-20 thousand mileage), the pump starts to work with overload, the pressure drops, and as a result, it becomes necessary to replace the pump.
Plastic parts for pump impeller and check valve wear out prematurely.
Pressure drops
It should be noted that the operation of the motor is possible at a pressure of up to 1.5 kg (with a standard 2.4-2.7 kg). At reduced pressure, there are constant lumbago in the intake manifold, the start is problematic (after). Draft is noticeably reduced. Check pressure correctly with a pressure gauge. (access to the filter is not difficult). In the field, you can use the "return filling test". If, when the engine is running, less than one liter flows out of the gas return hose in 30 seconds, it is possible to judge the reduced pressure. You can use an ammeter to indirectly determine the pump's performance. If the current consumed by the pump is less than 4 amperes, then the pressure is sagged.
You can measure the current on the diagnostic block.
When using a modern tool, the process of replacing the filter takes no more than half an hour. Previously, it took a lot of time. Mechanics always hoped in case that they were lucky and the lower fitting did not rust. But it often did.
I had to puzzle for a long time with which gas wrench to hook the rolled nut of the lower union. And sometimes the process of replacing the filter turned into a "movie show" with the removal of the tube leading to the filter.
Today, no one is afraid to make this replacement.
Control block
Before 1998 release,
the control units did not have enough serious problems during operation.
The blocks had to be repaired only for a reason"
hard polarity reversal"
... It is important to note that all outputs of the control unit are signed. It is easy to find on the board the required sensor lead to check,
or wire rings. Parts are reliable and stable at low temperatures.
In conclusion, I would like to dwell a little on gas distribution. Many owners "with hands" perform the belt replacement procedure on their own (although this is not correct, they cannot properly tighten the crankshaft pulley). Mechanics make a quality replacement within two hours (maximum). If the belt breaks, the valves do not meet the piston and the engine does not fatally break down. Everything is calculated to the smallest detail.
We tried to tell you about the most common problems on Toyota A series engines. The engine is very simple and reliable, and subject to very tough operation on "water-iron gasoline" and dusty roads of our great and mighty Motherland and the "awkward" mentality of the owners. Having endured all the bullying, it continues to delight to this day with its reliable and stable work, having won the status of the best Japanese engine.
All the early identification of problems and easy repair of the Toyota 4, 5, 7 A - FE engine!
Vladimir Bekrenev, Khabarovsk
Andrey Fedorov, Novosibirsk
© Legion-Avtodata
UNION OF AUTOMOTIVE DIAGNOSTS
You will find information on car maintenance and repair in the book (s):
In 1987, the Japanese auto giant Toyota launched a new series of engines for passenger cars, which was named "5A". Production of the series continued until 1999. The Toyota 5A engine was produced in three modifications: 5A-F, 5A-FE, 5A-FHE.
The new 5A-FE engine had a 4-valve DOHC valve per cylinder, that is, an engine fitted with two camshafts in the Double OverHead Camshaft, where each camshaft drives its own row of valves. With this arrangement, one camshaft drives two intake valves, the other two exhaust valves. The valves are usually driven by pushers. The DOHC scheme in the Toyota 5A series engines has significantly increased their power.
The second generation of Toyota 5A series engines
ATTENTION! Found a completely simple way to reduce fuel consumption! Don't believe me? An auto mechanic with 15 years of experience also did not believe until he tried it. And now he saves 35,000 rubles a year on gasoline!
An improved version of the 5A-F engine is the second generation 5A-FE engine. Toyota designers worked hard to improve the fuel injection system, as a result, the updated version of the 5A-FE was equipped with an electronic injection system EFI - Electronic Fuel Injection.
| Volume | 1.5 l. |
| Power | 100 h.p. |
| Torque | 138 N * m at 4400 rpm |
| Cylinder diameter | 78.7 mm |
| Piston stroke | 77 mm |
| Cylinder block | cast iron |
| Cylinder head | aluminum |
| Gas distribution system | DOHC |
| Fuel type | petrol |
| Predecessor | 3A |
| Successor | 1NZ |
Engines of modification toyota 5A-FE were equipped with cars of classes "C" and "D":
| Model | Body | Of the year | The country |
|---|---|---|---|
| Carina | AT170 | 1990–1992 | Japan |
| Carina | AT192 | 1992–1996 | Japan |
| Carina | AT212 | 1996–2001 | Japan |
| Corolla | AE91 | 1989–1992 | Japan |
| Corolla | AE100 | 1991–2001 | Japan |
| Corolla | AE110 | 1995–2000 | Japan |
| Corolla ceres | AE100 | 1992–1998 | Japan |
| Corona | AT170 | 1989–1992 | Japan |
| Soluna | AL50 | 1996–2003 | Asia |
| Sprinter | AE91 | 1989–1992 | Japan |
| Sprinter | AE100 | 1991–1995 | Japan |
| Sprinter | AE110 | 1995–2000 | Japan |
| Sprinter Marino | AE100 | 1992–1998 | Japan |
| Vios | AXP42 | 2002–2006 | China |
If we talk about the quality of the design, it is difficult to find a better motor. At the same time, the engine is very maintainable and does not give car owners difficulties in purchasing spare parts. The Japanese-Chinese joint venture Toyota and Tianjin FAW Xiali in China are still producing this engine for their small cars Vela and Weizhi.
Japanese motors in Russian conditions
5A-FE under the hood of Toyota Sprinter
Toyota car owners in Russia different models with engines of modification 5A-FE give a generally positive assessment performance characteristics 5A-FE. According to them, the 5A-FE resource is up to 300 thousand km. mileage. With further operation, problems with oil consumption begin. should be replaced with a mileage of 200 thousand km, after which the replacement should be done every 100 thousand km.
Many Toyota owners with 5A-FE engines are faced with a problem that manifests itself in the form of noticeable dips at medium engine speeds. This phenomenon, according to experts, is caused either by low-quality Russian fuel, or problems in the power supply and ignition system.
Subtleties of repair and purchase of a contract motor
Also, during the operation of 5A-FE motors, small disadvantages come to light:
- the engine is prone to high wear of the camshaft beds;
- fixed piston pins;
- difficulties sometimes arise with adjusting the clearances in the intake valves.
But, overhaul 5A-FE is a rare occurrence.
If it is necessary to replace the entire motor, by Russian market today you can easily find a contract 5A-FE engine in very good condition and at an affordable price. It is worth explaining that it is customary to call engines contract that have not been operated in Russia. Speaking about Japanese contract motors, it should be noted that most of them have low mileage and all manufacturer's requirements are met with respect to Maintenance... Japan has long been considered the world leader in terms of speed of renewal lineup cars. Thus, a lot of cars, engines of which have a fair supply of service life, end up on auto-dismantling there.
The most common and most widely repaired Japanese engine is the (4,5,7) A-FE series. Even a novice mechanic, diagnostician knows about possible problems with engines of this series. I will try to highlight (put together) the problems of these engines. There are not many of them, but they cause a lot of trouble to their owners.
Sensors.
Oxygen sensor - Lambda probe.
"Oxygen sensor" - used to fix oxygen in exhaust gases. Its role is invaluable in the fuel trim process. Read more about sensor problems in article.
Many owners turn to diagnostics for a reason increased fuel consumption ... One of the reasons is a banal break in the heater in the oxygen sensor. The error is fixed by the control unit code number 21. The heater can be checked with a conventional tester on the sensor contacts (R-14 Ohm). Fuel consumption increases due to the lack of fuel supply correction during warming up. You will not be able to restore the heater - only replacing the sensor will help. The cost of a new sensor is high, but it does not make sense to install a used one (the resource of their operating time is large, so this is a lottery). In such a situation, as an alternative, you can install equally reliable universal sensors NTK, Bosch or original Denso.
The quality of the sensors is not inferior to the original, and the price is significantly lower. The only problem could be correct connection When the sensor sensitivity decreases, the fuel consumption also increases (by 1-3 liters). The performance of the sensor is checked with an oscilloscope on the diagnostic connector block, or directly on the sensor chip (number of switchings). The sensitivity drops when the sensor is poisoned (contaminated) with combustion products.
Engine temperature sensor.
The "temperature sensor" is used to register the temperature of the motor. If the sensor does not work properly, the owner will face a lot of problems. In the event of a break in the measuring element of the sensor, the control unit replaces the sensor readings and fixes its value at 80 degrees and fixes error 22. The engine, with such a malfunction, will operate in normal mode, but only while the engine is warm. Once the engine has cooled down, it will be problematic to start it without doping, due to the short opening time of the injectors. It is not uncommon for the resistance of the sensor to change chaotically when the engine is running on H.H. In this case, the revolutions will float. This defect is easy to fix on the scanner, observing the temperature reading. On a warm engine, it should be stable and not change randomly from 20 to 100 degrees.
With such a defect in the sensor, a "black acrid exhaust" is possible, unstable operation on the Х.Х. and, as a result, increased consumption, as well as the impossibility of starting a heated engine. It will be possible to start the engine only after 10 minutes of rest. If there is no complete confidence in the correct operation of the sensor, its readings can be substituted by including a variable resistor of 1kΩ, or a constant 300Ω in its circuit, for further verification. By changing the sensor readings, it is easy to control the change in speed at different temperatures.
Throttle position sensor.
The throttle position sensor indicates to the on-board computer what position the throttle is in.
A lot of cars went through the disassembly assembly procedure. These are the so-called "constructors". When removing the engine in the field and subsequent assembly, the sensors suffered, on which the engine is often leaned against. If the TPS sensor breaks, the engine stops throttling normally. The engine chokes when accelerating. The machine switches incorrectly. The control unit fixes error 41. When replacing a new sensor, it must be configured so that the control unit correctly sees the X.X sign when the gas pedal is fully released (throttle valve closed). In the absence of a sign of idling, there will be no adequate regulation of X.X, and there will be no forced idle mode when braking by the engine, which again will entail increased fuel consumption. On engines 4A, 7A, the sensor does not require adjustment, it is installed without the possibility of rotation-adjustment. However, in practice, there are frequent cases of bending of the petal, which moves the sensor core. In this case, there is no sign of x / x. Adjustment of the correct position can be carried out using a tester without using a scanner - on the basis of idling.
THROTTLE POSITION …… 0%
IDLE SIGNAL ……………… .ON
MAP absolute pressure sensor
The pressure sensor shows the computer the real vacuum in the manifold, according to its readings, the composition of the fuel mixture is formed.
This sensor is the most reliable of all installed on Japanese cars. Its reliability is simply amazing. But it also has a lot of problems, mainly due to improper assembly. It either breaks the receiving "nipple", and then seals any air passage with glue, or breaks the tightness of the supply tube. With such a rupture, the fuel consumption increases, the level of CO in the exhaust increases sharply up to 3%. It is very easy to observe the sensor's operation using the scanner. The line INTAKE MANIFOLD shows the vacuum in the intake manifold, which is measured by the MAP sensor. If the wiring is broken, the ECU registers error 31. At the same time, the opening time of the injectors sharply increases to 3.5-5ms. When gas is re-gassed, a black exhaust appears, the candles are planted, a shaking appears on the X.H. and stopping the engine.
Knock sensor.
The sensor is installed to register detonation knocks (explosions) and indirectly serves as a "corrector" for the ignition timing.
The recording element of the sensor is a piezoplate. In the event of a sensor malfunction, or a break in the wiring, at overgasings of more than 3.5-4 tons. The ECU registers an error 52. You can check the performance with an oscilloscope, or by measuring the resistance between the sensor terminal and the case (if there is resistance, the sensor needs to be replaced).
Crankshaft sensor.
The crankshaft sensor generates pulses from which the computer calculates the engine speed. This is the main sensor by which all motor operation is synchronized.
A crankshaft sensor is installed on the 7A series engines. A conventional inductive sensor, similar to the ABC sensor, is practically trouble-free in operation. But embarrassment also happens. With a turn-to-turn closure inside the winding, the generation of pulses is disrupted at certain speeds. This manifests itself as a limitation of engine speed in the range of 3.5-4 t. Revolutions. A kind of cutoff, only at low revs. It is quite difficult to detect an interturn short circuit. The oscilloscope does not show a decrease in the amplitude of pulses or a change in frequency (with acceleration), and it is rather difficult to notice changes in Ohm fractions with a tester. If you experience symptoms of speed limitation at 3-4 thousand, just replace the sensor with a known good one. In addition, a lot of trouble is caused by damage to the driving ring, which is broken by mechanics when they replace the front crankshaft oil seal or timing belt. Having broken the teeth of the crown, and restoring them by welding, they achieve only a visible absence of damage. At the same time, the crankshaft position sensor ceases to adequately read information, the ignition timing begins to change chaotically, which leads to a loss of power, unstable engine operation and an increase in fuel consumption.
Injectors (nozzles).
Injectors are solenoid valves which inject pressurized fuel into the engine intake manifold. The operation of the injectors is controlled by the engine computer.
During many years of operation, the nozzles and needles of the injectors are covered with resins and gasoline dust. All this naturally interferes with the correct spray pattern and reduces the performance of the nozzle. In case of heavy pollution, noticeable shaking of the engine is observed, and fuel consumption increases. It is realistic to determine the clogging by conducting a gas analysis, according to the oxygen readings in the exhaust, it is possible to judge the correctness of the filling. A reading above one percent will indicate the need to flush the injectors (with the correct timing and normal fuel pressure). Or by installing the injectors on the stand, and checking the performance in tests, in comparison with the new injector. The nozzles are very efficiently washed by Laurel and Vince, both in CIP installations and in ultrasound.
Idle valve, IAC
The valve is responsible for the engine speed in all modes (warm-up, idle, load).
During operation, the valve petal becomes dirty and the stem wedges. The revolutions freeze on heating or on H.H. (due to a wedge). Tests for changing the speed in scanners during diagnostics for this motor are not provided. You can evaluate the valve's performance by changing the readings of the temperature sensor. Put the engine in "cold" mode. Or, removing the winding from the valve, twist the valve magnet with your hands. Sticking and wedge will be felt immediately. If it is impossible to easily dismantle the valve winding (for example, on the GE series), you can check its operability by connecting to one of the control outputs and measuring the duty cycle of the pulses, while simultaneously monitoring the speed of H.H. and changing the load on the engine. On a fully warmed-up engine, the duty cycle is approximately 40%, changing the load (including electrical consumers), it is possible to estimate an adequate increase in speed in response to a change in the duty cycle. With mechanical jamming of the valve, there is a smooth increase in the duty cycle, which does not entail a change in the speed of H.H. You can restore work by cleaning carbon deposits and dirt with a carburetor cleaner with the winding removed. Further adjustment of the valve is to set the H.H. speed. On a fully warmed up engine, by rotating the winding on the mounting bolts, tabular revolutions are achieved for this type of car (according to the tag on the hood). By pre-installing jumper E1-TE1 in the diagnostic block. On the "younger" motors 4A, 7A, the valve was changed. Instead of the usual two windings, a microcircuit was installed in the body of the valve winding. Changed the valve power and the color of the winding plastic (black). It is already pointless to measure the resistance of the windings at the terminals on it. The valve is supplied with power and a square-wave variable duty cycle control signal. For the impossibility of removing the winding, non-standard fasteners were installed. But the problem of the stock wedge remained. Now if you clean it with an ordinary cleaner, the grease is washed out from the bearings (the further result is predictable, the same wedge, but due to the bearing). It is necessary to completely dismantle the valve from the throttle body and then carefully flush the stem with a petal.
Ignition system. Candles.
A very large percentage of cars come to the service with problems in the ignition system. When operating on low-quality gasoline, spark plugs are the first to suffer. They are covered with a red coating (ferrosis). There will be no high-quality sparking with such candles. The engine will run intermittently, with gaps, fuel consumption increases, the level of CO in the exhaust rises. Sandblasting cannot clean such candles. Only chemistry (silite for a couple of hours) or replacement will help. Another problem is the increase in clearance (simple wear). Drying of the rubber tips of high-voltage wires, water that got during the washing of the motor, provoke the formation of a conductive track on the rubber tips.
Because of them, sparking will not be inside the cylinder, but outside it. With smooth throttling, the engine runs stably, and with sharp throttling, it crushes. In this position, it is necessary to replace both candles and wires at the same time. But sometimes (in the field), if replacement is impossible, you can solve the problem with an ordinary knife and a piece of emery stone (fine fraction). With a knife we cut off the conductive path in the wire, and with a stone we remove the strip from the ceramic of the candle. It should be noted that it is impossible to remove the rubber band from the wire, this will lead to the complete inoperability of the cylinder.
Another problem is related to the incorrect procedure for replacing the plugs. The wires are pulled out of the wells forcibly, ripping off the metal tip of the reins, causing misfires and floating rpm. When diagnosing the ignition system, always check the performance of the ignition coil on the high-voltage arrester. The simplest check is to look at the spark on the spark gap while the engine is running.
If the spark disappears or becomes threadlike, this indicates an interturn short circuit in the coil or a problem in the high-voltage wires. Wire breakage is checked with a resistance tester. Small wire 2-3kΩ, further to increase the long 10-12kΩ. The resistance of the closed coil can also be checked with a tester. The secondary resistance of the broken coil will be less than 12kΩ.
The next generation coils (remote) do not suffer from such ailments (4A.7A), their failure is minimal. Proper cooling and wire thickness eliminated this problem.
Another problem is the leaking oil seal in the distributor. Oil on the sensors corrodes the insulation. And when exposed to high voltage, the slider is oxidized (covered with a green coating). The coal turns sour. All this leads to the disruption of sparking. In motion, chaotic lumbago is observed (into the intake manifold, into the muffler) and crushing.
Subtle faults
On modern engines 4A, 7A, the Japanese changed the firmware of the control unit (apparently for faster engine warm-up). The change lies in the fact that the engine reaches H.H. rpm only at a temperature of 85 degrees. The design of the engine cooling system has also been changed. Now the small cooling circle passes intensively through the block head (not through the branch pipe behind the engine, as it was before). Of course, the cooling of the head has become more efficient, and the engine as a whole has become more efficient. But in winter, with such cooling when driving, the engine temperature reaches a temperature of 75-80 degrees. And as a result, constant warming up revolutions (1100-1300), increased fuel consumption and anxiety of the owners. You can deal with this problem either by insulating the engine more, or by changing the resistance of the temperature sensor (by deceiving the computer), or by replacing the thermostat for the winter with a higher opening temperature.
Butter
Owners pour oil into the engine indiscriminately, without thinking about the consequences. Few people understand that different types of oils are not compatible and, when mixed, form an insoluble slurry (coke), which leads to the complete destruction of the engine.
All this plasticine cannot be washed off with chemistry, it can only be cleaned mechanically. It should be understood that if you do not know what type of old oil, then you should use flushing before changing. And more advice to the owners. Pay attention to the color of the dipstick handle. It is yellow in color. If the color of the oil in your engine is darker than the color of the handle, then it's time to make a change, and not wait for the virtual mileage recommended by the engine oil manufacturer.
Air filter.
The most inexpensive and readily available element is the air filter. Owners very often forget about replacing it, without thinking about the likely increase in fuel consumption. Often, due to a clogged filter, the combustion chamber is very heavily contaminated with burned oil deposits, valves and candles are heavily contaminated. When diagnosing, it can be mistakenly assumed that the wear of the valve stem seals is to blame, but the root cause is a clogged air filter, which increases the vacuum in the intake manifold when contaminated. Of course, in this case, the caps will also have to be changed.
Some owners do not even notice about garage rodents living in the air filter housing. Which speaks of their utter disregard for the car.
The fuel filter is also noteworthy. If it is not replaced in time (15-20 thousand mileage), the pump starts to work with overload, the pressure drops, and as a result, it becomes necessary to replace the pump. The plastic parts of the pump impeller and non-return valve wear out prematurely.
Pressure drops. It should be noted that the operation of the motor is possible at a pressure of up to 1.5 kg (with a standard 2.4-2.7 kg). At reduced pressure, there are constant lumbago in the intake manifold, the start is problematic (after). Traction is noticeably reduced. Check the pressure correctly with a pressure gauge (access to the filter is not difficult). In the field, you can use the "return filling test". If, when the engine is running, less than one liter flows out of the gas return hose in 30 seconds, it is possible to judge the reduced pressure. You can use an ammeter to indirectly determine the pump's performance. If the current consumed by the pump is less than 4 amperes, then the pressure is sagged. You can measure the current on the diagnostic block. 
When using a modern tool, the process of replacing the filter takes no more than half an hour. Previously, it took a lot of time. Mechanics always hoped in case that they were lucky and the lower fitting did not rust. But it often did. I had to puzzle for a long time how to use a gas wrench to hook the rolled nut of the lower fitting. And sometimes the process of replacing the filter turned into a "movie show" with the removal of the tube leading to the filter. Today, no one is afraid to make this replacement.
Control block.
Until the 98th year of release, the control units did not have enough serious problems during operation. The blocks had to be repaired only because of the hard polarity reversal. It is important to note that all outputs of the control unit are signed. It is easy to find on the board the required sensor lead to check or wire continuity. Parts are reliable and stable at low temperatures.
In conclusion, I would like to dwell a little on gas distribution. Many owners "with hands" perform the belt replacement procedure on their own (although this is not correct, they cannot properly tighten the crankshaft pulley). Mechanics make a quality replacement within two hours (maximum). If the belt breaks, the valves do not meet the piston and the engine does not fatally break down. Everything is calculated to the smallest detail.
We tried to tell you about the most common problems on engines of this series. The engine is very simple and reliable, and under the condition of very tough operation on "water - iron gasoline" and dusty roads of our great and mighty Motherland and the "auto" mentality of the owners. Having endured all the bullying, it continues to delight to this day with its reliable and stable work, having won the status of the most reliable Japanese engine.
Vladimir Bekrenev, Khabarovsk.
Andrey Fedorov, Novosibirsk.
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