Octane number
General advice and recommendations from the manufacturer - "What gasoline do we pour into Toyota?"

Engine oil
General tips for choosing engine oil - "What kind of oil do we pour into the engine?"

Spark plug
General notes and catalog of recommended candles - "Spark plug"

Batteries
Some recommendations and a catalog of standard batteries - "Batteries for Toyota"

Power
A little more about the characteristics - "Rated performance characteristics of Toyota engines"

Refueling tanks
Manufacturer's Guide - "Filling volumes and liquids"

The most archaic OHV engines for the most part remained in the 1970s, but some of their representatives were modified and remained in service until the mid-2000s (K series). The lower camshaft was driven by a short chain or gears and moved the rods through hydraulic pushers. Today, OHV is used by Toyota only in the truck diesel segment.

From the second half of the 1960s, SOHC and DOHC engines of various series began to appear - initially with solid double-row chains, with hydraulic compensators or adjusting valve clearances with washers between the camshaft and the pusher (less often with screws).

The first series with a timing belt drive (A) was born only in the late 1970s, but by the mid-1980s such engines - what we call "classics" - became an absolute mainstream. First SOHC, then DOHC with the letter G in the index - "wide Twincam" with the drive of both camshafts from the belt, and then the massive DOHC with the letter F, where one of the shafts connected by a gear was driven by a belt. Clearances in DOHC were adjusted by washers above the pushrod, but some motors with Yamaha-designed heads retained the principle of placing the washers under the pushrod.

When the belt broke on most mass-produced engines, valves and pistons did not occur, with the exception of forced 4A-GE, 3S-GE, some V6s, D-4 engines and, of course, diesel engines. In the latter, due to the design features, the consequences are especially severe - valves bend, guide bushings break, and the camshaft often breaks. For gasoline engines, chance plays a certain role - in a “non-bending” engine, the piston and valve covered with a thick layer of soot sometimes collide, and in a “bending”, on the contrary, valves can successfully hang in a neutral position.

In the second half of the 1990s, fundamentally new engines of the third wave appeared, on which the timing chain drive returned and mono-VVT (variable intake phases) became standard. As a rule, chains drove both camshafts on in-line engines, on V-shaped ones, a gear drive or a short additional chain was between the camshafts of one head. Unlike the old double-row chains, the new long single-row roller chains were no longer durable. Valve clearances were now almost always set by the selection of adjusting tappets of different heights, which made the procedure too laborious, time-consuming, costly, and therefore unpopular - for the most part, the owners simply stopped monitoring the clearances.

For engines with a chain drive, cases of breakage are traditionally not considered, however, in practice, when the chain slips or is incorrectly installed, in the vast majority of cases, valves and pistons meet each other.

A peculiar derivation among the engines of this generation was the forced 2ZZ-GE with variable valve lift (VVTL-i), but in this form the concept of distribution and development did not receive.

Already in the mid-2000s, the era of the next generation of engines began. In terms of timing, their main distinguishing features are Dual-VVT (variable phases at the inlet and outlet) and the revived hydraulic compensators in the valve drive. Another experiment was the second option for changing the valve lift - Valvematic on the ZR series.

The practical advantages of a chain drive compared to a belt drive are simple: strength and durability - the chain, relatively speaking, does not break and requires less frequent scheduled replacements. The second gain, layout, is important only for the manufacturer: the drive of four valves per cylinder through two shafts (also with a phase change mechanism), the drive of the high-pressure fuel pump, pump, oil pump - require a sufficiently large belt width. Whereas installing a thin single-row chain instead of it allows you to save a couple of centimeters from the longitudinal size of the engine, and at the same time reduce the transverse size and distance between the camshafts, due to the traditionally smaller diameter of sprockets compared to pulleys in belt drives. Another small plus is less radial load on the shafts due to less preload.

But we must not forget about the standard minuses of the chains.
- Due to the inevitable wear and the appearance of play in the hinges of the links, the chain is stretched during operation.
- To combat chain stretch, either a regular "pulling" procedure is required (as on some archaic motors), or the installation of an automatic tensioner (which is what most modern manufacturers do). The traditional hydraulic tensioner works from the general engine lubrication system, which negatively affects its durability (therefore, on new generation chain engines, Toyota places it outside, simplifying replacement as much as possible). But sometimes the stretching of the chain exceeds the limit of the adjusting capabilities of the tensioner, and then the consequences for the engine are very sad. And some third-rate automakers manage to install hydraulic tensioners without ratchet, which allows even an unworn chain to “play” with every start.
- The metal chain in the process of work inevitably "saw through" the shoes of the tensioners and dampers, gradually wears out the sprockets of the shafts, and the wear products get into the engine oil. Even worse, many owners do not change sprockets and tensioners when replacing a chain, although they must understand how quickly an old sprocket can ruin a new chain.
- Even a serviceable timing chain drive always works noticeably noisier than a belt drive. Among other things, the speed of the chain is uneven (especially with a small number of sprocket teeth), and when the link enters the engagement, a blow always occurs.
- The cost of the chain is always higher than the timing belt kit (and some manufacturers are simply inadequate).
- Replacing the chain is more laborious (the old "Mercedes" method does not work on Toyotas). And in the process, a fair amount of accuracy is required, since the valves in Toyota chain engines meet pistons.
- Some Daihatsu-derived engines use toothed chains instead of roller chains. By definition, they are quieter in operation, more accurate and more durable, but for inexplicable reasons they can sometimes slip on sprockets.

As a result - have the maintenance costs decreased with the transition to timing chains? A chain drive requires this or that intervention at least as often as a belt drive - hydraulic tensioners are rented, on average, the chain itself stretches over 150 t.km ... and the costs "per circle" are higher, especially if you do not cut out the details and replace all the necessary components at the same time drive.

The chain can be good - if it is two-row, in an engine of 6-8 cylinders, and there is a three-beam star on the cover. But on classic Toyota engines, the timing belt was so good that the transition to thin long chains was a clear step back.

In the post-Soviet space, the carburetor power supply system for locally produced cars will never have competitors in terms of maintainability and budget. All deep electronics - EPHH, all vacuum - automatic UOZ and crankcase ventilation, all kinematics - throttle, manual suction and drive of the second chamber (Solex). Everything is relatively simple and understandable. A penny cost allows you to literally carry a second set of power and ignition systems in the trunk, although spare parts and "dokhtura" could always be found somewhere nearby.

Toyota carburetor is a completely different matter. Just look at some 13T-U of the turn of the 70-80s - a real monster with a lot of vacuum hose tentacles ... Well, the later "electronic" carburetors generally represented the height of complexity - a catalyst, an oxygen sensor, air bypass to exhaust, bypass exhaust gases (EGR), electric suction control, two or three stages of idle control on load (electrical consumers and power steering), 5-6 pneumatic actuators and two-stage dampers, ventilation of the tank and float chamber, 3-4 electro-pneumatic valves, thermo-pneumatic valves, EPHX, vacuum corrector , air heating system, a full set of sensors (coolant temperature, intake air, speed, detonation, DZ limit switch), catalyst, electronic control unit ... It's surprising why such difficulties were needed at all if there were modifications with normal injection, but either way otherwise, such systems, tied to vacuum, electronics and drive kinematics, worked in a very delicate balance. The balance was broken in an elementary way - not a single carburetor is immune from old age and dirt. Sometimes everything was even more stupid and simpler - an excessively impulsive "master" disconnected all the hoses in a row, but, of course, he did not remember where they were connected. Somehow it is possible to revive this miracle, but it is extremely difficult to establish the correct operation (to simultaneously maintain a normal cold start, normal warm-up, normal idle, normal load correction, normal fuel consumption). As you might guess, a few carburetors with knowledge of Japanese specifics lived only within Primorye, but after two decades, even local residents are unlikely to remember them.

As a result, Toyota distributed injection initially turned out to be simpler than late Japanese carburetors - there were not much more electrics and electronics in it, but the vacuum degenerated a lot and there were no mechanical drives with complex kinematics - which gave us such valuable reliability and maintainability.

The most unreasonable argument in favor of the D-4 is as follows - "direct injection will soon replace traditional engines." Even if this were true, it would in no way indicate that there is no alternative to LV engines already Now. For a long time, D-4 was understood, as a rule, in general, one specific engine - 3S-FSE, which was installed on relatively affordable mass-produced cars. But they were completed only three Toyota models from 1996-2001 (for the domestic market), and in each case the direct alternative was at least the version with the classic 3S-FE. And then the choice between D-4 and normal injection was usually preserved. And since the second half of the 2000s, Toyota generally abandoned the use of direct injection on engines in the mass segment (see. "Toyota D4 - prospects?" ) and began to return to this idea only ten years later.

"The engine is excellent, we just have bad gasoline (nature, people ...)" - this is again from the field of scholasticism. Let this engine be good for the Japanese, but what is the use of this in the Russian Federation? - a country of not the best gasoline, a harsh climate and imperfect people. And where instead of the mythical advantages of the D-4, only its shortcomings come out.

It is extremely dishonest to appeal to foreign experience - "but in Japan, but in Europe" ... The Japanese are deeply concerned about the far-fetched problem of CO2, the Europeans combine blinkers on reducing emissions and efficiency (it's not for nothing that more than half of the market there is occupied by diesel engines). For the most part, the population of the Russian Federation cannot compare with them in terms of income, and the quality of local fuel is inferior even to states where direct injection was not considered until a certain time - mainly because of unsuitable fuel (besides, the manufacturer of a frankly bad engine can be punished there with a dollar) .

Stories that "the D-4 engine consumes three liters less" are just plain misinformation. Even according to the passport, the maximum savings of the new 3S-FSE compared to the new 3S-FE on one model was 1.7 l / 100 km - and this is in the Japanese test cycle with very quiet conditions (so the real savings were always less). With dynamic city driving, the D-4, operating in power mode, does not in principle reduce consumption. The same thing happens when driving fast on the highway - the zone of tangible efficiency of the D-4 in terms of speed and speed is small. And in general, it is incorrect to talk about the "regulated" consumption for a car that is by no means new - it depends to a much greater extent on the technical condition of a particular car and driving style. Practice has shown that some of the 3S-FSE, on the contrary, consume significantly more than 3S-FE.

One could often hear "yes, you will change the cheap pump quickly and there are no problems." Whatever you say, but the obligation to regularly replace the main assembly of the engine fuel system with respect to a fresh Japanese car (especially a Toyota) is simply nonsense. And even with a regularity of 30-50 t.km, even "penny" $ 300 became not the most pleasant waste (and this price concerned only 3S-FSE). And little was said about the fact that the nozzles, which also often required replacement, cost money comparable to high-pressure fuel pumps. Of course, the standard and, moreover, already fatal problems of the 3S-FSE in terms of the mechanical part were carefully hushed up.

Perhaps not everyone thought about the fact that if the engine has already "caught the second level in the oil pan", then most likely all the rubbing parts of the engine suffered from working on a benzo-oil emulsion (you should not compare grams of gasoline that sometimes get into the oil when cold start-up and evaporating with the engine warming up, with liters of fuel constantly flowing into the crankcase).

No one warned that on this engine you should not try to "clean the throttle" - that's all correct adjusting the elements of the engine control system required the use of scanners. Not everyone knew about how the EGR system poisons the engine and coke the intake elements, requiring regular disassembly and cleaning (conditionally - every 30 t.km). Not everyone knew that trying to replace the timing belt with the "similarity method with 3S-FE" leads to a meeting of pistons and valves. Not everyone could imagine if there was at least one car service in their city that successfully solved the problems of D-4.

Why is Toyota valued in the Russian Federation in general (if there are Japanese brands cheaper-faster-sportier-more comfortable-..)? For "unpretentiousness", in the broadest sense of the word. Unpretentiousness in work, unpretentiousness to fuel, to consumables, to the choice of spare parts, to repairs ... You can, of course, buy high-tech squeezes for the price of a normal car. You can carefully choose gasoline and pour a variety of chemicals inside. You can recalculate every cent saved on gasoline - whether the costs of the upcoming repairs will be covered or not (excluding nerve cells). It is possible to train local servicemen in the basics of repairing direct injection systems. You can remember the classic "something has not broken for a long time, when will it finally fall down" ... There is only one question - "Why?"

In the end, the choice of buyers is their own business. And the more people contact HB and other dubious technologies, the more customers the services will have. But elementary decency still requires to say - buying a car with a D-4 engine in the presence of other alternatives is contrary to common sense.

Retrospective experience allows us to assert that the necessary and sufficient level of emission reduction was already provided by the classic engines of the Japanese market models in the 1990s or by the Euro II standard in the European market. All that was required for this was distributed injection, one oxygen sensor and a catalyst under the bottom. Such cars worked for many years in a standard configuration, despite the disgusting quality of gasoline at that time, their own considerable age and mileage (sometimes completely exhausted oxygen tanks required replacement), and it was easy to get rid of the catalyst on them - but usually there was no such need.

The problems began with the Euro III stage and correlating standards for other markets, and then they only expanded - the second oxygen sensor, moving the catalyst closer to the outlet, switching to "cat collectors", switching to wide-band mixture composition sensors, electronic throttle control (more precisely, algorithms, deliberately worsening the response of the engine to the accelerator), increased temperature conditions, fragments of catalysts in the cylinders ...

Today, with the normal quality of gasoline and much more recent cars, the removal of catalysts with a flashing of an ECU of the Euro V> II type is massive. And if for older cars, in the end, it is possible to use an inexpensive universal catalyst instead of an obsolete one, then for the freshest and "intelligent" cars there is simply no alternative to breaking through the collector and software disabling emission control.

A few words on individual purely "environmental" excesses (gasoline engines):
- The exhaust gas recirculation (EGR) system is an absolute evil, as soon as possible it should be turned off (taking into account the specific design and the presence of feedback), stopping the poisoning and contamination of the engine with its own waste products.
- The evaporative emission system (EVAP) - works fine on Japanese and European cars, problems arise only on North American market models due to its extreme complexity and "sensitivity".
- Exhaust air supply (SAI) - an unnecessary but relatively harmless system for North American models.

In fact, the abstract recipe for the best engine is simple - gasoline, R6 or V8, aspirated, cast-iron block, maximum safety margin, maximum working volume, distributed injection, minimum boost ... but alas, in Japan this can only be found on cars clearly "anti-people "class.

In the lower segments available to the mass consumer, it is no longer possible to do without compromises, so the engines here may not be the best, but at least “good”. The next task is to evaluate the motors taking into account their actual application - whether they provide an acceptable thrust-to-weight ratio and in what configurations they are installed (an ideal engine for compact models will be clearly insufficient in the middle class, a structurally more successful engine may not be aggregated with all-wheel drive, etc.) . And, finally, the time factor - all our regrets about the excellent engines that were discontinued 15-20 years ago do not mean at all that today we need to buy ancient worn-out cars with these engines. So it only makes sense to talk about the best engine in its class and in its time period.

1990s Among classic engines, it is easier to find a few unsuccessful ones than to choose the best from a mass of good ones. However, the two absolute leaders are well known - 4A-FE STD type "90" in the small class and 3S-FE type "90 in the middle class. In a large class, 1JZ-GE and 1G-FE type "90 are equally worthy of approval.

2000s As for the engines of the third wave, there are only good words for the 1NZ-FE type "99 for the small class, while the rest of the series can only compete for the title of an outsider with varying success, in the middle class there are even no "good" engines. to pay tribute to 1MZ-FE, which turned out to be not bad at all against the background of young competitors.

2010s. In general, the picture has changed a little - at least the engines of the 4th wave still look better than their predecessors. In the lower class, there is still 1NZ-FE (unfortunately, in most cases this is the "modernized" type "03" for the worse). In the older segment of the middle class, the 2AR-FE performs well. As for the large class, according to a number of economic and political reasons for the average consumer it no longer exists.

However, it is better to see with examples how the new versions of the engines turned out to be worse than the old ones. About 1G-FE type "90 and type" 98 has already been said above, but what is the difference between the legendary 3S-FE type "90" and type "96"? All deteriorations are caused by the same "good intentions", such as reducing mechanical losses, reducing fuel consumption, reducing CO2 emissions. The third point refers to the completely insane (but beneficial for some) idea of ​​a mythical fight against mythical global warming, and the positive effect of the first two turned out to be disproportionately less than the resource drop...

Deteriorations in the mechanical part refer to the cylinder-piston group. It would seem that the installation of new pistons with trimmed (T-shaped in projection) skirts to reduce friction losses could be welcomed? But in practice, it turned out that such pistons begin to knock when shifting to TDC at much shorter runs than in the classic type "90. And this knock does not mean noise in itself, but increased wear. It is worth mentioning the phenomenal stupidity of replacing fully floating piston pressable fingers.

Replacing the distributor ignition with DIS-2 in theory is characterized only positively - there are no rotating mechanical elements, longer coil life, higher ignition stability ... But in practice? It is clear that it is impossible to manually adjust the basic ignition timing. The resource of new ignition coils, in comparison with classic remote ones, even fell. The resource of high-voltage wires has expectedly decreased (now each candle sparked twice as often) - instead of 8-10 years, they served 4-6. It's good that at least the candles remained simple two-pin, and not platinum.

The catalyst has moved from under the bottom directly to the exhaust manifold in order to warm up faster and get to work. The result is a general overheating of the engine compartment, a decrease in the efficiency of the cooling system. It is unnecessary to mention the notorious consequences of the possible ingress of crushed catalyst elements into the cylinders.

Instead of pairwise or synchronous fuel injection, on many types of type "96, fuel injection became purely sequential (into each cylinder once per cycle) - more accurate dosage, loss reduction, "ecology" ... In fact, gasoline was now given before entering the cylinder much less time for evaporation, therefore, start-up characteristics at low temperatures automatically deteriorated.

More or less reliably, we can only talk about the "resource before the bulkhead", when the engine of the mass series required the first serious intervention in the mechanical part (not counting the replacement of the timing belt). For most classic engines, the bulkhead fell on the third hundred run (about 200-250 t.km). As a rule, the intervention consisted in replacing worn or stuck piston rings and replacing valve stem seals - that is, it was just a bulkhead, and not a major overhaul (the geometry of the cylinders and hone on the walls were usually preserved).

Next generation engines often require attention already in the second hundred thousand kilometers of run, and in the best case, it costs to replace the piston group (in this case, it is advisable to change the parts to those modified in accordance with the latest service bulletins). With a noticeable waste of oil and the noise of piston shifting on runs over 200 t.km, you should prepare for a big repair - severe wear of the liners leaves no other options. Toyota does not provide for the overhaul of aluminum cylinder blocks, but in practice, of course, the blocks are re-sleeved and bored. Unfortunately, reputable companies that really do high quality and professionally overhaul modern "disposable" engines throughout the country can really be counted on the fingers. But peppy reports of successful re-engineering today come from mobile collective farm workshops and garage cooperatives - what can be said about the quality of work and the resource of such engines is probably understandable.

This question is posed incorrectly, as in the case of "absolutely the best engine." Yes, modern motors cannot be compared with classic ones in terms of reliability, durability and survivability (at least with the leaders of past years). They are much less maintainable mechanically, they become too advanced for unskilled service...

But the fact is that there is no alternative to them anymore. The emergence of new generations of motors must be taken for granted and each time re-learn how to work with them.

Of course, car owners should in every possible way avoid individual unsuccessful engines and especially unsuccessful series. Avoid engines of the earliest releases, when the traditional "running on the buyer" is still underway. If there are several modifications of a particular model, you should always choose a more reliable one - even if you sacrifice either finances or technical characteristics.

P.S. In conclusion, one cannot fail to thank Toyot for the fact that it once created engines “for people”, with simple and reliable solutions, without the frills inherent in many other Japanese and Europeans. And let the owners of cars from “advanced and advanced” manufacturers disparagingly called them kondovy - so much the better!

"The simplest Japanese engine"

Engines 5А,4А,7А-FE
The most common and today the most widely repaired of Japanese engines is the engines of the (4,5,7) A-FE series. Even a novice mechanic, diagnostician knows about the possible problems of engines of this series. I will try to highlight (collect into a single whole) 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 really 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 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 correction during warm-up. You will not be able to restore the heater - only a replacement will help. The cost of a new sensor is high, and it makes no sense to install a used one (their operating time is large, so this is a lottery). In such a situation, less reliable universal NTK sensors can be installed as an alternative. The term of their work is short, and the quality leaves much to be desired, so such a replacement is a temporary measure, and it should be done with caution.

When the sensor sensitivity decreases, fuel consumption increases (by 1-3 liters). The operability of the sensor is checked by an oscilloscope on the diagnostic connector block, or directly on the sensor chip (number of switching).

Temperature sensor.
If the sensor does not work correctly, the owner will have a lot of problems. If the measuring element of the sensor breaks, the control unit replaces the sensor readings and fixes its value by 80 degrees and fixes error 22. The engine, with such a malfunction, will operate normally, but only while the engine is warm. As soon as the engine cools down, it will be problematic to start it without doping, due to the short opening time of the injectors. There are frequent cases when the resistance of the sensor changes randomly when the engine is running at H.X. - 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 randomly change values ​​from 20 to 100 degrees.

With such a defect in the sensor, a “black exhaust” is possible, unstable operation on H.X. and, as a result, increased consumption, as well as the inability to start "hot". Only after 10 minutes of sludge. If there is no complete confidence in the correct operation of the sensor, its readings can be replaced by including a 1 kΩ variable resistor or a constant 300 ohm resistor in its circuit for further verification. By changing the readings of the sensor, the change in speed at different temperatures is easily controlled.

Throttle position sensor

A lot of cars go through the process of assembly and disassembly. These are the so-called "constructors". When removing the engine in the field and subsequent assembly, the sensors suffer, on which the engine is often leaned. When the TPS sensor breaks, the engine stops throttling normally. The engine bogs down when revving. The machine switches incorrectly. Error 41 is fixed by the control unit. When replacing a new sensor, it must be adjusted so that the control unit correctly sees the sign of X.X., with the gas pedal fully released (throttle closed). In the absence of a sign of idling, adequate regulation of H.X. will not be carried out. and there will be no forced idling mode 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

MAP absolute pressure sensor

This sensor is the most reliable of all installed on Japanese cars. His resilience 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 gap, fuel consumption increases, the level of CO in the exhaust increases sharply up to 3%. It is very easy to observe the operation of the sensor on the scanner. The line INTAKE MANIFOLD shows the vacuum in the intake manifold, which is measured by the MAP sensor. When 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. and stop the engine.

Knock sensor

The sensor is installed to register detonation knocks (explosions) and indirectly serves as a "corrector" of the ignition timing. The recording element of the sensor is a piezoelectric plate. In the event of a sensor malfunction, or a break in the wiring, at over 3.5-4 tons of revs, the ECU fixes error 52. Sluggishness is observed during acceleration. You can check the performance with an oscilloscope, or by measuring the resistance between the sensor output and the housing (if there is resistance, the sensor needs to be replaced).

crankshaft sensor
On 7A series engines, a crankshaft sensor is installed. A conventional inductive sensor is similar to the ABC sensor and is practically trouble-free in operation. But there are also confusions. With an interturn circuit inside the winding, the generation of pulses at a certain speed is disrupted. This manifests itself as a limitation of engine speed in the range of 3.5-4 tons of revolutions. A kind of cut-off, only at low speeds. It is quite difficult to detect an interturn circuit. The oscilloscope does not show a decrease in the amplitude of the pulses or a change in frequency (during acceleration), and it is rather difficult for a tester to notice changes in Ohm's shares. If you experience symptoms of speed limit at 3-4 thousand, simply replace the sensor with a known good one. In addition, a lot of trouble causes damage to the master ring, which is damaged by negligent mechanics while replacing the front crankshaft oil seal or timing belt. Having broken the teeth of the crown, and restored 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 randomly, which leads to loss of power, unstable engine operation and increased fuel consumption

Injectors (nozzles)

During many years of operation, the nozzles and needles of the injectors are covered with tar and gasoline dust. All this naturally interferes with the correct spray and reduces the performance of the nozzle. With severe pollution, a noticeable shaking of the engine is observed, fuel consumption increases. It is realistic to determine clogging by conducting a gas analysis; according to the readings of oxygen in the exhaust, one can judge the correctness of 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 the tests. Nozzles are easily cleaned by Lavr, Vince, both on CIP machines and in ultrasound.

Idle valve, IACV

The valve is responsible for engine speed in all modes (warm-up, idling, load). During operation, the valve petal becomes dirty and the stem is wedged. Turnovers hang on warming up or on X.X. (due to the wedge). Tests for changes in speed in scanners during diagnostics for this motor are not provided. The performance of the valve can be assessed by changing the readings of the temperature sensor. Enter the engine in the "cold" mode. Or, having removed the winding from the valve, twist the valve magnet with your hands. Jamming 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 controlling the RPM. and changing the load on the engine. On a fully warmed-up engine, the duty cycle is approximately 40%, by changing the load (including electrical consumers), an adequate increase in speed in response to a change in duty cycle can be estimated. When the valve is mechanically jammed, a smooth increase in the duty cycle occurs, which does not entail a change in the speed of H.X. You can restore work by cleaning soot and dirt with a carburetor cleaner with the winding removed.

Further adjustment of the valve is to set the speed X.X. On a fully warmed up engine, by rotating the winding on the mounting bolts, they achieve tabular revolutions for this type of car (according to the tag on the hood). Having previously installed the jumper E1-TE1 in the diagnostic block. On the “younger” 4A, 7A engines, the valve has been changed. Instead of the usual two windings, a microcircuit was installed in the body of the valve winding. We changed the valve power supply and the color of the winding plastic (black). It is already pointless to measure the resistance of the windings at the terminals. The valve is supplied with power and a control signal of a rectangular shape with a variable duty cycle.

To make it impossible to remove 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 of the bearings (the further result is predictable, the same wedge, but already because of the bearing). It is necessary to completely dismantle the valve from the throttle body and then carefully flush the stem with the 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 work intermittently, with gaps, fuel consumption increases, the level of CO in the exhaust rises. Sandblasting is not able to clean such candles. Only chemistry (silit for a couple of hours) or replacement will help. Another problem is the increase in clearance (simple wear). Drying of the rubber lugs of high-voltage wires, water that got in when washing the motor, which all provoke the formation of a conductive path on the rubber lugs.

Because of them, sparking will not be inside the cylinder, but outside it.
With smooth throttling, the engine runs stably, and with a sharp one, it “crushes”.

In this situation, it is necessary to replace both the candles and the 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 ceramics 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 candles. The wires are pulled out of the wells with force, tearing off the metal tip of the rein.

With such a wire, misfires and floating revolutions are observed. When diagnosing the ignition system, you should always check the performance of the ignition coil on the high-voltage arrester. The simplest test is to look at the spark gap on the spark gap with the engine running.

If the spark disappears or becomes filiform, this indicates an inter-turn short circuit in the coil or a problem in the high voltage wires. A wire break is checked with a resistance tester. Small wire 2-3k, then to increase the long 10-12k.

The closed coil resistance can also be checked with a tester. The resistance of the secondary winding of the broken coil will be less than 12 kΩ.
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 current oil seal in the distributor. Oil, falling 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 disruption of sparking. In motion, chaotic shootings are observed (into the intake manifold, into the muffler) and crushing.

" Subtle "faults"
On modern 4A, 7A engines, the Japanese have changed the firmware of the control unit (apparently for faster engine warm-up). The change is that the engine reaches idle speed only at 85 degrees. The design of the engine cooling system was also changed. Now a small cooling circle intensively passes through the head of the block (not through the 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 during movement, the temperature of the engine reaches a temperature of 75-80 degrees. And as a result, constant warm-up revolutions (1100-1300), increased fuel consumption and nervousness 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 computer).
Oil
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 porridge (coke), which leads to the complete destruction of the engine.

All this plasticine cannot be washed off with chemistry, it is cleaned only mechanically. It should be understood that if it is not known what type of old oil, then flushing should be used before changing. And more advice to the owners. Pay attention to the color of the oil dipstick handle. He is yellow. If the color of the oil in your engine is darker than the color of the pen, it's time to change instead of waiting for the virtual mileage recommended by the engine oil manufacturer.

Air filter
The most inexpensive and easily accessible 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 polluted with burnt oil deposits, valves and candles are heavily contaminated. When diagnosing, it can be erroneously 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 that garage rodents live in the air filter housing. Which speaks of their complete disregard for the car.

Fuel filter also 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. The plastic parts of the pump impeller and check valve wear out prematurely.

The 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 shots into the intake manifold, the start is problematic (after). The draft is noticeably reduced. It is correct to check the pressure 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 gasoline return hose in 30 seconds, it can be judged that the pressure is low. You can use an ammeter to indirectly determine the performance of the pump. If the current consumed by the pump is less than 4 amperes, then the pressure is squandered. 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, this took a lot of time. Mechanics always hoped in case they were lucky and the bottom fitting did not rust. But often that is what happened. I had to rack my brains for a long time with which gas wrench to hook the rolled-up 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 change.

Control block
Until 1998, 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 conclusions of the control unit are signed. It is easy to find on the board the necessary sensor output for checking, or continuity of the wire. The parts are reliable and stable in operation at low temperatures.
In conclusion, I would like to dwell a little on gas distribution. Many “hands on” owners 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 there is no fatal destruction of the engine. Everything is calculated to the smallest detail.

We tried to talk about the most common problems on the engines of this series. The engine is very simple and reliable, and subject to very tough operation on “water-iron gasolines” and dusty roads of our great and mighty Motherland and the “maybe” mentality of the owners. Having endured all the bullying, to this day he continues to delight with his reliable and stable work, having won the status of the best Japanese engine.

All the best with your repairs.

Vladimir Bekrenev
Khabarovsk

Andrey Fedorov
Novosibirsk city