rich smelly and farty

[themixer]

i think a compression test is in order, i am pretty sick of replacing everything. Its still working a lot better with the new computer.

[themixer]

*bump, another year is starting and i am still having this same issue with my 3.1 anyone run into any issues like this over the last year :S

[themixer]

OK everyone I really need help now, got the car back from the dealer they did a compression test all cylinders tested fine 150-160. First he diagnosed it as a computer issue then i sent the list of what i have replaced on the car. I have been chasing the problem for YEARS now. The mechanic said that it drove fine without misfires, which is a load of crap. Pulling out of the dealership today, it stalled hard started with a cloud of black smoke out of the exhaust.

I feel this has to be some sort of fuel issue, there are no vacuum leaks. I am going to pull the injectors again and swap in another set.

I went out and replaced the computer tonight with one that was out of a 1989 cavalier z24. And again 0% change

I am going to get the scan tool back again and start looking at the problem closer.

I really want to finally have a 5 speed 3.1 that idles smooth and has no hesitation.

[Money pit Beretta]

Did you ever try the coolant temp sensor?

[themixer]

Yes sadly I am getting some detailed diagnostics from the tech 1 will be posting soon

[themixer]

Here is the tech 1 sorry about the video length I don't use this thing often I was just messing around with it but the data is all there
http://www.youtube.com/watch?v=SAVEK89f4EE

for a comparison here is the data from my perfect running 2.8
http://www.youtube.com/watch?v=-QtxG-uAD_Y


from the differences i see:

injector pluse width --> 89 is 2+ - 91 is 1.0-1.1ms

map --> 89 is 43Kpa --> 91 is 36Kpa

anyone see anything out of the ordinary ?

[themixer]

Does anyone know a cause of the ECU adjusting the BLM to a low value. From what I have read this is trimming fuel attempting to run the car leaner.

Could this be caused by low fuel Volume as my pressure is fine.

Took off the intake last night all the injectors tested 12.3-12.9

My injector harness looks like it was modified at some point but I checked with someone else and I guess this is factory. I tested to be sure there was no shorts in this cable. It seems the front 3 cylinders are wired parallel and same with the back 3. From what I have read in the manual this is accurate.

Is there any possibility of this being my CPS? Is there any test I can do to see if it is working as it should be?

[3X00-Modified]

Lower map reading aka higher number could be pointing to a vac leak or bad map sensor which could make it dump extra fuel. The leak may not be enough to cause it to run lean as a typical vac leak would, but the map sensor reading in the 40's would make it run on richer tables.

[themixer]

the 3.1 was reading 37 and the good running 2.8 was 43 I can take the map out of the running car tonight to see if it makes a difference. But I feel as if I am chasing my tail again. I wish something would just break and the car would stop running so I could replace it.

[3X00-Modified]

Oh I got that backwards then... I thought the car with the higher reading injector MS flow was the one running rich. And if that's not the case then I would look at swapping the injectors out, as they may have all ohm'd ok that doesn't mean one isn't stuck open and leaking, hence a lower MS reading but richer smell

[themixer]

i will change them out tonight and post results tomorrow

[themixer]

changed out the injectors with the originals and the car is actually better, i got about 100km more on my last tank of fuel. it has changed the way the car sounds when its missing. something else interesting about this is the set of flow matched injectors that i got were actually quite different looking that what was original to the car. I am surprised that I didn't question that before installing. I am on the hunt for a set of 6 working injectors, may just end up taking them off my running 2.8 for a test.


Here are the ones i took out

[3X00-Modified]

Those look like 3100 injectors, but that should be fine for that engine.

[woody90gtz]

If the ECM is pulling fuel (BLM under 128) then it knows it is running too rich and is trying to lean it out. Pretty much rules it out as a source of your problem and points to a mechanical issue. Running rich it would not be an issue with insufficient fuel either. And swapping injectors should rule out a sticky injector causing it to run rich.

Have you tested for leaky injectors by pulling the rail and injectors and cycling the fuel pump on? If you leave the injectors installed on the rail there should be no leaks anywhere when pressurized.

It sounds to me like that would be the cause...one injector leaks and causes the o2 to read rich. The ECM tries to lean out the fuel mixture and it runs the other cylinders too lean causing a misfire.

[themixer]

By mechanical issue do you mean the injectors ? As the compression test came back good

I did cycle the key with the flow matched injectors and there were no leaks, I will try to pull it apart and try this test on the original ones.