7A-FE Lean Burn - Toyota Carina, 1.8L, 2010
The 7A-FE engine was created in 1993, naturally on the basis of the 4A-FE. Its differences are in the increased volume of the combustion chamber (1.8 liters versus 1.6) and a completely different torque characteristic.
This is a unique engine of its kind. Its maximum torque is already reached at 2800 rpm! This gives tangible fuel economy (engine efficiency is increased) and significantly improves the vehicle's elasticity (acceleration from standstill). For city traffic jams and "start-stop" driving modes, this is just a gift! At the same time, the engine, due to its gasoline nature, does not lose its functionality at high vehicle speeds :).
As someone once correctly noted, "power is what sells a car, and torque is what drives it" ...
Although Toyota began its experiments with leaning the mixture back on the 4A-FE in 1992, all the stereotypes and rumors about this system had to be taken over by the 7A - I don't know why.
It should be remembered and never forgotten that there are two parallel versions of 4A-FE and 7A-FE engines for the Japanese market - "regular" and lean burn! The usual ones were put on the Corolla family (Carib, Spacio), and the "poor" ones on the Corona (Carina, Caldina).
So, the "lean" version of the 7A-FE differs from the "normal" mixture depletion system (it is also a variable intake manifold). With the help of special flaps in the intake manifold, the mixture is leaner and in light modes the engine runs on it. This allows significant fuel savings in exchange for a small loss of power (about 5 hp). It also improves the environmental behavior of the engine.
The electronics that control the engine have their own original opinion about when to turn on the lean mixture :). It is known for sure that this system does not work at idle, just as it sharply changes the frequency of its activation depending on the automatic transmission mode (I don't even know how all this is implemented on a car with a manual transmission) (if you drive with the over-drive turned off, then the depletion occurs only when the gas pedal is fully released).
Switching modes happens very quickly - just let the system know that you want to move at a faster pace - that is, press the accelerator harder :). There is no "brooding" poor "system" about which there are rumors!
You can read more about the mixture depletion system on the 4A-FE / 7A-FE on the Internet (however, they usually talk about the European version of this system and the information is often confusing). For example, here.
Differences from the usual 7A are also in the arrangement of the nozzles. Here they sit almost in the valve cover itself, deep. They also work not in parallel, but "each for itself".
In addition to the "Japanese" differences between the two versions of these engines, there are also options for the European market. They use a special lambda probe - a lean mixture sensor. And in Japanese it is a completely ordinary oxygen sensor. The system of flaps in the intake manifold is also different, and, until 1997, these engines existed with a distributor ignition system.
Of course, Toyota is not the only manufacturer of such engines. For example, Nissan's SR18DE and QG18DE units have a similar system.
Ignition and candles
It should also be noted that the "poor" engine received a different ignition system - contactless (there is no distributor), such as DIS-2 on two ignition coils (one for two cylinders). The main advantage of this system is that there is no need to correct the ignition angle (the electronics itself does this using a knock sensor).
In general, the LB system is designed in such a way that it requires a larger spark to ignite the mixture, as well as a more frequent formation of these sparks. It turns out naturally that the ignition system of this engine is more picky about the quality of sparking.
Most often spark plugs suffer on these engines. It's all about low-quality gasoline, which forms a conductive coating on the central insulator. And the candle just starts to junk - the engine (and the car) jerks in lean mixture modes, first in motion, and then simply at low engine speeds at idle. Candles need to be replaced.
What to change for? The platinum-plated candles offered by Toyota, with two electrodes and a gap of 1.3 mm, are quite expensive and do not realize their potential at all on Russian fuel - they simply "blush" with a bloom just like any others (and serve not the prescribed 60 thousand km, but only 5! ).
Let's figure it out: platinum and two-electrode are needed to extend the life of the plug, which works in the "devouring" plug system stronger than usual. A gap of 1.3 mm is needed to get a more powerful spark ... Thus, we can take almost any spark plug with a gap of 1.3. The only problem is that there are usually no such (non-platinum) ones :)). The solution was found simply - take the candles with a gap of 1.1 and unbend the electrode (s), increasing the gap. You can also use a gap of 1.1, but lean burn then starts to somehow "save fuel badly" and its consumption increases ...
So, I recommend using NGK BKR5EKB-11 with extended electrodes instead of the laid NGK BKR5EKPB-13 . Or similar from another manufacturer. Two-electrode - just in case (all of a sudden, gasoline is still not so bad, and suddenly the combustion of the mixture in the cylinder is somehow oriented towards a greater openness of the central electrode - it is not known for sure).
Most importantly, beware of counterfeit candles! For example, in Japan, as of the summer of 2004, "regular" candles cost $ 5 and platinum candles cost $ 8. Think how much they should cost in Russia - certainly not cheaper.
Fuel
This engine is designed for the so-called regular fuel. This is the Japanese analogue of gasoline with an octane rating of AI-92. Naturally unleaded.
Russian experience has confirmed that the 7A-FE LB quietly consumes AI-92, even of not the best quality. And, on the contrary, it is better to abandon AI-95, which almost always contains more additives that "kill" the spark plugs.
Oil seals
When replacing the timing belt and its tension roller (every 100 thousand km. Run), you may want to replace the engine oil seals. Because for both of these operations, you will have to lift the engine from its seat.
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Karina was with 7a - a superb engine.
I also bought her new armored wires and changed the candles every time I changed the oil - the engine just whispered.
where do you live ? I live in the opera of the world, we do not have benz but a slurry smelling of acetone)) and 46 liters per liter))))
at the expense of benz, I can argue lil is always 95 and does not kill anything (candles) a friend had the same engine he poured only 92 after 20,000 km replacement of candles showed that his 92 benza candles are just black, I have excellent so do not write nonsense about benz
photo boxes throw I doubt that on platinum so much on our benz you can drive. I switched to iridium back in 12. I drove for 3 years until they were eaten to the electrode, this is 50 thousand, we sell iridiums only because they are problem-free,
they are with one contact and the platinum is old with 2 mustaches
on the first platinum, I left 80 thousand for the second, I already ride 40, it seems normal) but the fact that the wire needs to be changed is yes, NGK runs 60 thousand already, but on the third cylinder I had to change the wire, began to sew on a candle (the car twitched under load, detonated )
Zvonkyi
ehhh bought a car a month ago, I'll write what I did) I just don't like it when something is wrong with the car))) first of all I changed the fuel pump with a mesh, then cleaned the force, then the droselka (everything as you wrote) replaced the fuel, clutch kit, candles, BB seem to be new (but I also look at them already) checked on diagnostics (all the rules) I fiddled up the engine (but she ate up the oil, of course - all the oil was stuck), but the problem remained, stupidity from 1800 to 2600 approximately, especially felt at 2 oh transmission, and by the way, from the morning to the cold one rides perfectly easily and not forcedly (but the truth is literally 1 minute) then again, as if they are holding the ass)
this motor loves iridium candles. Platinum on our gasoline does not run more than 10 thousand, I immediately put in the iridium enough for 50 thousand km, and you need to change it along with the wires. otherwise he just won't go. The main reason is the poor mixture for economy.
Zvonkyi
ehhh bought a car a month ago, I'll write what I did) I just don't like it when something is wrong with the car))) first of all I changed the fuel pump with a mesh, then cleaned the force, then the droselka (everything as you wrote) replaced the fuel, clutch kit, candles, BB seem to be new (but I also look at them already) checked on diagnostics (all the rules) I fiddled up the engine (but she ate up the oil, of course - all the oil was stuck), but the problem remained, stupidity from 1800 to 2600 approximately, especially felt at 2 oh transmission, and by the way, from the morning to the cold one rides perfectly easily and not forcedly (but the truth is literally 1 minute) then again, as if they are holding the ass)
Perhaps the sensor, the lambda umbrella is not working properly, which is screwed into the manifold.
I won't tell you about the new ones! you can look for a contractual one, but it's better to remove it altogether =)
Do it, report the result =)
I understood the ATP - I will poke around further) they are new, and they are generally sold at least)
Looked at the fuses in the block under the hood? Once I heard from one karinovoda that when he had a similar problem, he changed the entire fuse box ... it is not so expensive, about 1000 ... And the problem was solved!
But I still advise you to turn off the LEARN BURN chip that goes behind the engine under EFI ... and try to ride like that!
In general, LEARN BURN engines should not be pressed into the seat, they were created to a greater extent to save fuel, due to smooth acceleration and a quiet ride!
it seems to me that if you turn off the sensor, the car will not go at all
I must try, I just unhooked the hose from the sensor, that is, the flap opened, as I understand it, the car did not want to go at all
If you turn it off, then nothing bad will happen, the maximum consumption will increase slightly!
So I also think about this sensor, but if you turn off the chip, should it go? and now I gas at idle, this valve does not react as it does, but when the ignition is turned off, it opens, and the car closes at the factory. I don't want him to press it - but he doesn't eat normally))) the fuses are normal. when the collector was removed, this damper was tin like a shit, I think that most likely this sensor does not work.
Looked at the fuses in the block under the hood? Once I heard from one karinovoda that when he had a similar problem, he changed the entire fuse box ... it is not so expensive, about 1000 ... And the problem was solved!
But I still advise you to turn off the LEARN BURN chip that goes behind the engine under EFI ... and try to ride like that!
In general, LEARN BURN engines should not be pressed into the seat, they were created to a greater extent to save fuel, due to smooth acceleration and a quiet ride!
ehhh bought a car a month ago, I'll write what I did) I just don't like it when something is wrong with the car))) first of all I changed the fuel pump with a mesh, then cleaned the force, then the droselka (everything as you wrote) replaced the fuel, clutch kit, candles, BB seem to be new (but I also look at them already) checked on diagnostics (all the rules) I fiddled up the engine (but she ate up the oil, of course - all the oil was stuck), but the problem remained, stupidity from 1800 to 2600 approximately, especially felt at 2 oh transmission, and by the way, from the morning to the cold one rides perfectly easily and not forcedly (but the truth is literally 1 minute) then again, as if they are holding the ass)
The Internet is full of information regarding KXX, have you tried searching?
For example, from personal experience I can tell you that whoever ever cleaned it before you, so it makes sense to disassemble the throttle body and gently clean the throttle and valve with a brush with gasoline (cleaning fluid)! Only when you disassemble, look carefully with rubber gaskets, if they are stuck then do not touch them, if they are unstuck, then remove them carefully and just put them aside, then as you clean them, put them on, otherwise they will tear with a bang = (but also when you will remove the sensor with KXX, then put the marks in which position it stood and the bolts on it, otherwise you will have to look later by ear for XX ...
Everything will work out, there is nothing complicated there! =)
if it does not help in this case, then try to fuck LEARN BURN, I won't tell you exactly how, but the electrician should know, but the Internet will help you again!
And how can you check the KXX valve yourself? P / S since I already went through the move better but did not help, you can ride a little on a cold ride and again for the old one (
and the loss of power for a heated one, is especially felt from 2 x to 3 x thousand? Can the candles be or timing?
can of course! I have a carina with 7A-FE on the fur and also an LB with a distributor. This is the first LB engine! As for the candles - I also advise you to put them in the catalog and not stir up anything! otherwise it starts to gore fuel and twitching at idle!
Hello! I am reading your topic and I cannot understand, I have a 7a-fe motor. upon a detailed study, it turned out that he was just lean burn, because there are flaps at the end of the intake manifold, but it is distributor. It can be or is it already something that has been altered ?!
Kisel-KGD
Does this engine have hydraulic lifters?
Toyota is somehow skeptical about them ... even on new Kruzaks, for example, the valves are regulated! It is possible on other machines the same way.
Thank you well laid out everything! Especially about the candles, otherwise the dergatsa already began to seize. I bought a motor there were already irides, I need to change to simple ones, although they should be platinum, let's see what happens.
I have a question - is it possible to convert the distributor LB to coils? and is there any sense and advantages in this?
Hello! Please tell me. I have 4 a. How can I turn it into a 7a with minimal difficulty? Karina 190 (smile) LB
You disassemble it, there is an elastic band similar to the one you have torn. use it
Is it possible to put an ignition timing vacuum instead of a valve that opens the manifold flaps on the lb motor?
you can read in more detail what kind of valve is from the classics, otherwise my forehead valve does not work at all
Can you tell me how to cope with the moment of valve opening, so that it would not work at 4500, but at 3500?