Compression Results

[ForcedFirebird]

I wouldn't doubt the larger injectors did it. Larger injectors without a matching chip does nothing for anyone.

[dude8383]

What did the leakdown numbers say? I don't recall seeing that anywhere.

Its weird that you're getting coolant in the airbox. Similar to what happened when my first motor took a dump at Summit Point Main. It regurgitated a bunch of coolant out the intake ... cylinder 3 blew up into bits. I don't know what happened with that motor but it had a cooling issue... maybe headgasket failure or a bad head. Can't comment on that with certainty.

Adam, remember the knock we heard? Could that be detonation??

Secondly... could detonation be causing the RICH mixture? (I'm not very knowledgeable here I admit).

[digger]

What did the leakdown numbers say? I don't recall seeing that anywhere.

Its weird that you're getting coolant in the airbox. Similar to what happened when my first motor took a dump at Summit Point Main. It regurgitated a bunch of coolant out the intake ... cylinder 3 blew up into bits. I don't know what happened with that motor but it had a cooling issue... maybe headgasket failure or a bad head. Can't comment on that with certainty.

Adam, remember the knock we heard? Could that be detonation??

Secondly... could detonation be causing the RICH mixture? (I'm not very knowledgeable here I admit).

post #5

[EyExR]

I wouldn't doubt the larger injectors did it. Larger injectors without a matching chip does nothing for anyone.

It's SSSquid chipped for my car with M50 injectors. Although I now have a spare ECU in there at the moment for testing purposes. The M50 injectors are 17.5# so not much of a difference really... But I'm going to swap back to the M20 injectors just to test.

What did the leakdown numbers say? I don't recall seeing that anywhere.

Its weird that you're getting coolant in the airbox. Similar to what happened when my first motor took a dump at Summit Point Main. It regurgitated a bunch of coolant out the intake ... cylinder 3 blew up into bits. I don't know what happened with that motor but it had a cooling issue... maybe headgasket failure or a bad head. Can't comment on that with certainty.

Adam, remember the knock we heard? Could that be detonation??

Secondly... could detonation be causing the RICH mixture? (I'm not very knowledgeable here I admit).

The wet air filter is a mystery. I'll crack that box open again and see what's up now with a fresh one in there.

My gut feeling is that I'm losing compression from bore wash. My car has been getting the 1222 code for quite some time. Ignorant me never knew that could polish my cylinder walls. But now I know and the rich condition is now enemy #1

post #5

Yes. Cylinder #4 was dropping by about 30%. All the others looked good. Listened for air passing and it was real loud coming out of my dip stick tube.

I'm now thinking it could possibly be a bad purge valve. So I'll cap that at the intake and see. I've read that a bad purge valve can cause a car to run rich. I don't see how but I'll test it.

I also did not mention that I'm using an E34 O2 sensor because I have long tube headers installed. I hope that it's compatible as everywhere I've read says it is.

[ForcedFirebird]

Rich conditions is a big enemy on fresh rings, especially.

M50 injectors with a chip is fine. People put them in because they think it will make the car run better, but working on these things every day for a living, the spark plugs tell me otherwise. Every car that comes in with larger injectors (yes, even 17.5) have spark plugs covered in soot.

[EyExR]

Rich conditions is a big enemy on fresh rings, especially.

M50 injectors with a chip is fine. People put them in because they think it will make the car run better, but working on these things every day for a living, the spark plugs tell me otherwise. Every car that comes in with larger injectors (yes, even 17.5) have spark plugs covered in soot.

Good to know. thanks

[EyExR]

Doing electrical tests the Bentley says to move the sensor flap on the AFM and the resistance should fluctuate. But by what values???

As I move the flap resistance increases but then seems to decrease the farther I push it. Does this make any sense?

[digger]

when i last had an AFM and was doing some diagnoisis i found this site helpful http://www.the944.com/afm.htm

[EyExR]

when i last had an AFM and was doing some diagnoisis i found this site helpful http://www.the944.com/afm.htm

Thanks Digger! Yeah, the guys at OMG sent me the same link. I did all the tests and it came back perfect. The hunt continues.....

I'm getting my old M20 blue top injectors rebuilt and will try that next. If that doesn't do anything I'm going to put in a Magnaflow Cat and replace my O2 sensor again. Then that would be everything.

The only other thing I can think of is an intake leak at the break booster. I'm not sure how to test that and will do some research....

OMG smoke tested and I only had a couple of small leaks which I believe I've taken care of. I will get it smoke tested again before all is said and done. And I'll have the exhaust smoke tested as well.

I'm also thinking that the bad cylinder rings could now be adding to the air/fuel mixture problem. Is that possible?

[ForcedFirebird]

Yes, oil can skew 02 readings, but if you unplug the o2 sensor and reset your ECU, it will default to a stock table. If the car runs cleaner after that, the o2 is suspect.

[Lugnuts]

Try replacing your crank position sensor. I had the same resistance reading on mine and I strongly suspect it was the cause of detonation in my engine (plastic housing, made by Vemo?). Replacement unit with a metal housing reads the expected 540 ohms and things are better. Not perfect, but I think what's left can be resolved with a decent tune.

[EyExR]

Yes, oil can skew 02 readings, but if you unplug the o2 sensor and reset your ECU, it will default to a stock table. If the car runs cleaner after that, the o2 is suspect.

And then plug it back in, correct?

I tried this. CEL came on again...

[EyExR]

Try replacing your crank position sensor. I had the same resistance reading on mine and I strongly suspect it was the cause of detonation in my engine (plastic housing, made by Vemo?). Replacement unit with a metal housing reads the expected 540 ohms and things are better. Not perfect, but I think what's left can be resolved with a decent tune.

Yes, I was thinking about this last night and was reading up on how the CPS sends signals to the ECU.

I didn't realize there were two types. I will try to track one down with the metal housing... Anyone have a part number handy?

[ForcedFirebird]

And then plug it back in, correct?

I tried this. CEL came on again...

No, drive it with fresh spark plugs and the o2 unplugged. Ignore the CEL while doing it.

[EyExR]

No, drive it with fresh spark plugs and the o2 unplugged. Ignore the CEL while doing it.

Oh okay. Gotcha! So I'm looking for fouled plugs, right? About how long should I drive the car for?