Astra F 1.6 8V - uneven work and goes out at idle, suddenly loses power

Hello, I have a problem with my 1991 Astra F Estate 1.6 8V. I recently bought it and am having a few problems with it.

The first and most troublesome problem is uneven operation and engine stalling at idle. While driving and at slightly higher revs, the engine behaves completely normally, while at idle you can feel the inside of the car slight jerks of the engine and when you put your hand in the exhaust pipe, you feel that the exhaust gases are not escaping evenly. It goes off in such a way that after a dozen or so seconds of idling, its revolutions suddenly drop to such that it almost goes out, then comes a few more seconds and then it goes off. Sometimes, especially when it is cold, it happens that it goes out at the first such sudden drop in RPM. Today I changed the stepper motors and mine is probably fine, because the others behaved very similarly, but one of them caused the engine to revolve over 3,000 right after firing it, so there was something wrong with it.

The second problem is the sudden loss of power during acceleration. It manifests itself in such a way that by accelerating and holding the pedal in the floor, e.g. on a number two or three, the engine suddenly stops pulling, there is no reaction to the gas pedal and the revs drop and after 3-4 seconds everything returns to normal and the car accelerates further. The impression is as if you turn the ignition key off for a moment and then turn it on again. It happens only after a few seconds or a dozen or so seconds of fully pressing the gas pedal, when the gas pedal is handled delicately, this situation does not occur.

I have already bought the car with the oil replaced recently, the fuel filter, the one close to the tank, the dome, high voltage cables, candles (there are some two electrodes) and I think with a finger but I'm not sure about it.

The first stage of my diagnostics was checking the compression and on each cylinder 12 bar came out, so everything was fine. Then I made a jumper in the diagnostic socket so that I could read the errors and the numbers 35 and 45 came out (according to the knowledge from the Internet: 35 - Engine idle stepper - deviation from the set number of revolutions, 45 - Lambda-probe - exhaust gas too rich)

I am asking for advice on where to start, if it helps, I can make a video of the engine running at idle speed. Thanks in advance.

You have mistakes, start with them. Check the probe. How do you know the rest of the motors are working?

I got 4 other engines to check and apart from one of them the car behaved the same, so I think they were functional, but I am not sure about it.

How to check the probe? Is it in the place I marked? (photo not mine)

The probe is in the place you indicated - measure the voltage because it is supposed to change, there is only one positive cable.

Did you clean the throttles? EGR not syphony? LPG or only gasoline?

The car does not have LPG and, as far as I know, it did not have either.

I understand, I will go to the probe voltage in a moment.

As for cleaning the throttle, I'm not sure if it requires it, because removing the black "box" covering the injection, the entire channel, including the throttle, looks very clean, so I do not know if the previous owner was already messing with it (maybe that's how he broke the sterile ones speed) or maybe the air filter was very effective in catching all impurities.

I will try to find and clean EGR according to the guides available on the Internet.

I do not know if it will help, but when starting a cold or slightly cooled engine, it works very nicely for a few seconds without touching the gas pedal, after this time it starts to work unevenly and goes out.

Added after 1 [hours] 47 [minutes]:

I checked the lambda probe readings, the values on the slightly warm engine show about 0.5V, after gasification they reach about 0.8V. I have already removed the EGR and I am starting to clean it, before unscrewing it, I unscrewed the vacuum controlling its operation and the engine idled exactly the same as with the connected one.

Added after 1 [hours] 14 [minutes]:

EGR seems to be cleaned. I rinsed its lower part (through which the exhaust fumes pass) with the engine cleaner and with a brush I dug up what I could. Unfortunately, it didn't help.

Quote:

As for cleaning the throttle, I'm not sure if it requires it, because removing the black "box" covering the injection, the entire channel, including the throttle, looks very clean, so I do not know if the previous owner was already messing with it (maybe that's how he broke the sterile ones speed) or maybe the air filter was very effective in catching all impurities.


I do not know if it will help, but when starting a cold or slightly cooled engine, it works very nicely for a few seconds without touching the gas pedal, after this time it starts to work unevenly and goes out.

The throttle does not get dirty from air - only odmy oil. It is important whether the channel from the stepper motor is functional, what you can see from above is basically nothing. Since on a cold gun (there is certainly a more open circuit on the stepper and higher revs), it is something with regulation, matching the motor. Do you have the original one? After unplugging the battery, so that the settings are reset and firing in neutral also goes out after time? The adaptation of the stepper motor is said to be leaving it in neutral until it warms up. But if it works, I will not cut off my arm.

Air filter clean? There is some leakage on the way to the throttle by accident? Are the throttle seals tight?

Thank you for your answer.

Today I still struggled with this idle speed, although what I did today was nothing special, because I only sealed the pipe connecting the air filter with the mono-injection can. It was already patched with tape by the previous owner so I thought it would be good to do it again and now I am sure the left air will not get there.

Earlier, I tried to remove this pipe to make sure that the air filter did not choke the engine and I even removed the mono-injection can and even without it, the engine ran as badly as before.

Today, however, before unscrewing this box, I unplugged the battery, thinking that maybe it would do something (although I had already unplugged it and it did not work) and after a few or a dozen minutes I connected it again and, surprisingly, the engine, although it did not work perfectly evenly, as the watch did not go out already at idle, in addition, probably unknowingly, I made him this adaptation of the stepper motor that enhanced wrote about, because I let it heat up until the fan turned on, waiting for it to finally go out, although it did not happen. Surprised, I went for a ride without the mono-injection cover and the engine did not go out. After the ride, I put everything back together as it should be and the engine did not go out.

After all, I checked the errors and again 35 and 45 popped out, i.e. from the stepper motor and the lambda probe (too rich mixture). It's hard for me to understand why today the engine suddenly stopped stalling and started idling normally, maybe tomorrow will be like before.

The air filter has not yet been changed in my tenure, although in my opinion it does not look dirty. Leaks on the way to the throttle I think I eliminated. If the question about the gaskets at the throttle concerned the connection of the plastic box screwed to the injection with the entire injection, I do not know how to check the tightness of this connection, although I do not think that is the reason. All the stepper motors I tested came from scrap and I think they were original.

I deliberately did not call the idling engine undulating, but uneven work, because listening to the sound from the exhaust I have the impression that ignition has fallen out. It seems to me that the rippling moment before the engine goes out is a consequence of lowered RPM due to misfiring. The dome, candles and wires are new, so it's probably not their fault.

As for the error with the lambda probe, error 45 means too rich mixture, i.e. the probe probably works correctly recognizing the composition of the mixture, because if it were not, another error would pop up, e.g. regarding a break in the probe circuit or no change in its voltage.

You already did a lot to seal the pipe - because it was pulling the left air. And there is to go the appropriate heated air from the filter (air is taken to the filter above the exhaust outlet from the engine).

And how did the car perform? It gathers correctly without breaks, does not dim too much when braking in neutral?

All the mushrooms of these motors are the same because they may differ in this mushroom. I changed it myself, although it probably turned out that the left (cold) air was approaching the place where the cable to the injector in the base of this plastic housing is. There is a gasket in its entirety, and in this place there is an additional gasket on the conduit (it has broken down in my case).

Both of these errors occurred during a stop or during a test drive?

At one time, I also had a damaged inlet pipe and there were circuses when braking, especially because it silted it - I replaced it with a new one without playing with tapes. It gives me confidence and it actually improved right away because before the exchange I had to throw in the cap to cool the astra (I have x16 with lpg).

While driving, it collects and collects really well (especially from low revs), better than my 90 hp Escort MK7 station wagon, I have the impression that today when braking in neutral the revs were higher than before, and it did not go out once, which was the norm before .

Perhaps the second problem described in the first post was caused by insufficient fuel in the tank, because when I experienced it, the reserve light was on, but not for too long.

What mushrooms are you writing about? I know that mushrooms are called EGRs in these engines, but you probably mean the air inlet and in my case it is visible behind the grill and to be honest I do not know how warm air would get there. However, I still doubt whether the air intake to the throttle is the cause of my problems because, on the other hand, people put cones on, not paying attention to where the air is coming from and whether everything is tight and somehow they drive (probably) without any problems.

Mushroom, i.e. the head of the stepper - they are finished in different ways (this metal tip), which you would not put on some other because probably something will not work properly. Some are truncated and not truncated.

There is also such a mushroom in the EGR, of course, because it closes / opens the passage of exhaust gases, as in the case of a stepper, the amount of air.

Maybe the cones work somewhere, but here we originally have a warm air inlet (Adjustable - this hose from the mono-injection housing going to the air filter housing) and there is a regulation of how much of this warm air goes to the air filter. The main intake is of course cold air in front of the radiator.

Are you saying it's working properly now? Only he still has these bugs - the question of how often he catches them.

enhanced wrote:

Maybe the cones work somewhere, but here we originally have a warm air inlet (Adjustable - this hose from the mono-injection housing going to the air filter housing) and there is a regulation of how much of this warm air goes to the air filter. The main intake is of course cold air in front of the radiator.

Well, actually, earlier I was wondering why this pipe from the exhaust manifold goes to the air filter box and that would explain why the vacuum goes to this can.

As for the errors, the yellow light with the engine appeared when it was idling immediately after connecting the battery, so he caught the errors quite quickly.

Since the improvement, I drove this car only a few kilometers and during this time it drove well, it did not go out, tomorrow I will drive it a little further, it will turn out. Thank you very much for your answers once again.

Today I drove Astra several kilometers and the engine did not go out even once. The yellow engine light was not displayed while driving, although the errors are probably still in the computer. On the longer route, I will check how the fuel consumption looks like and if it is normal, I will let it go, even though the engine still does not idle perfectly as well as a watch.

I enjoy this fact. It does not work smoothly on the idle ones right away or after a short stop I will ask out of curiosity? The turnover is at what position?

Immediately after starting the cold engine, it works well, slightly warm, probably also, and only after these several seconds it starts to work unevenly. For now, I have not driven this car enough to find out everything about it, and I have had it recently. Unfortunately, I do not know what the revolutions are, because as I wrote, the tachometer does not work for me and it probably involves the replacement of the entire meter and honestly I do not want to do it. I will keep you informed on this topic in the event of developments. Thanks for your help again.