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Discussion Starter · #1 · (Edited)
Hi folks, as per the title, Astra H (A16XER) giving me a hard time in the morning.
As I start the car (it takes a bit more turning than I think it should) it starts OK, then after 5-10 seconds, it starts spluttering and almost stalls, then recovers and the revs go up to 1500 then drop. After 5-10 seconds it does it again, and so on for a couple of times. If I try to take off while it does this, there is almost no power and the engine misfires like hell. The colder it gets in the morning, the more obvious are the issues that the car has.
When I plug in the OPCOM (HQ) there are some strange values that I see, wonder if anyone can confirm is this right.
1. TPS values for sensor 1 and 2 are not changing no mater at what RPM the car is running.
2. Throttle PWM servo value dance around 90% and it slightly changes if I press the pedal hard.
I thought those values are/should be related to the throttle plate position.
Could it be that the OPCOM is reading incorrectly? Is there any other way (besides probing with DVOM) that I could check the TPS?
What points me in the TPS direction is that the car acceleration is pretty bad and the car seems like it has no power and is not responding well (jerking, slow acc. etc.) but on occasions (very rare) it drives almost like it should.
P.S. APP sensors 1 and 2, IAT and coolant temp sensor values are looking to be OK and there are no codes or EML.
Hope that someone will have some advice...
 

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Discussion Starter · #4 ·
Update: Noticed that when this is happening (the stalling of the engine), the MAP sensor reports increase in pressure from 30-something kpa to almost 80kpa but the throttle is not opening and there is no increase in engine load. After it recovers, the intake pressure (or vacuum) returns to 30-ish kpa. As if there is something that starts to open and lets in air (I know, sounds stupid) and the mixture is just not in the right range for it to combust. Does this engine has some additional "port" that is used for idle speed regulation, or the MAP is just buggered?
 

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I would remove the o2 sensor myself, would be noisy though, you may be able to view the internals of the cat from there.
I only thought about the exhaust with you saying it almost stalls then recovers, as if the gases build up and then get away
I think a good garage could measure the back pressure and verfy it is in spec.
 

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Discussion Starter · #8 ·
I would remove the o2 sensor myself, would be noisy though, you may be able to view the internals of the cat from there.
I only thought about the exhaust with you saying it almost stalls then recovers, as if the gases build up and then get away
I think a good garage could measure the back pressure and verfy it is in spec.
Sounds logical and could quite easily be the issue I'm facing, the only thing that is bothering me is that it only happens when it's really cold outside. I just can't wrap my head around it, it almost sounds like a CTS, except that it's not, since both CTS's report the right coolant temperature, so does the IAT.
 

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Sounds logical and could quite easily be the issue I'm facing, the only thing that is bothering me is that it only happens when it's really cold outside. I just can't wrap my head around it, it almost sounds like a CTS, except that it's not, since both CTS's report the right coolant temperature, so does the IAT.
I did think of that also, as it tends to fuel incorrectly for a cold start if faulty. It is mainly the engine cts that would cause it. You could buy a new engine cts, cheap enough and just plug it in electrically without fitting it to thermostat housing and try a few cold starts.
 

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Discussion Starter · #10 ·
I did think of that also, as it tends to fuel incorrectly for a cold start if faulty. It is mainly the engine cts that would cause it. You could buy a new engine cts, cheap enough and just plug it in electrically without fitting it to thermostat housing and try a few cold starts.
I would definitely try that, but I'm curious about one more thing. Do you think it's possible that the exhaust is restricted because it's full of water (condensation)? I'm asking because when you mentioned it yesterday, I remembered that my mother in law had a problem with her Peugeot 206, loss of power, spluttering and what not, and the garage found that the exhaust is full of water, since she only drives short distances, not being able to evaporate it. Just a thought, though a crazy one...
 

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I would definitely try that, but I'm curious about one more thing. Do you think it's possible that the exhaust is restricted because it's full of water (condensation)? I'm asking because when you mentioned it yesterday, I remembered that my mother in law had a problem with her Peugeot 206, loss of power, spluttering and what not, and the garage found that the exhaust is full of water, since she only drives short distances, not being able to evaporate it. Just a thought, though a crazy one...
I very much doubt it being condensation myself. Let us know how you go on.
 
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