Missing and running very rich (Was: Help needed)

[map 87 gn]

Hello All,

I am having trouble with my 87 GN. Here is a brief problem & what I have done so far.
The car misses while it's running but worse between 1850 to 2000 rpm. When it is missing it is running very rich (enough to leave black soot on the ground) & it's not trowing any codes.
Here is what I have done so far, 1 step at a time with no changes to the problem.
- changed MAF twice, reset ECM,
- checked TPS voltage with no dead spots or drops when it is missing
- checked the fuel pressure with no changes when it is missing
- checked AF on scanmaster when it's missing & the reading doesn't change
- changed IGN module twice & coil pack twice
- changed spark plugs wires & spark plugs (all plugs were black from burning too rich)
- checked & rechecked all air hoses to make certain there was no leaks

I am at a wall. I have no clue what to look/check for next. Does anyone have any suggestions?
Thanks for any forthcoming help

[PaCemkr86]

with it running try unplugging the cam sensor and see if it smooths out.
It would be alot easier to diagnose if you could post a powerlogger file

[map 87 gn]

Thanks for the suggestion..I will try that over the weekend.
Sorry I have no powerlogger just a scanmaster.

[PaCemkr86]

are all the dip switches in your translator set correct

[map 87 gn]

Yes they are...sorry I forgot to mention that.

[dmoberg]

I sympathize with you my friend. Might wanna check your connections again, I had a similar experience nearly drove me nuts.....hairline crack leaking air around the intercooler under increased rpms. Also had an intermittent coil pack that was somewhat similar too. Sounds like all the sensors are doing the job though...no codes, sorta points to a physical problem. My 2 cents....

[Keller]

Are the symptoms present both in gear and out of gear?

Any differences between in gear and out of gear behavior?

[Keller]

Originally Posted by PaCemkr86

with it running try unplugging the cam sensor and see if it smooths out.

Might try the same thing with the MAF.

I assume that it is pointing the correct direction...

[Keller]

Also, check timing. The crank trigger wheel may have moved on the balancer.

[map 87 gn]

Thanks dmoberg I will recheck the intercooler to see if there is a crack somewhere. I will also check all the connections again. Never hurts to double check.


Thanks Keller. Yes the symptoms are present both in gear & out of gear & there is no changes between both. The MAF is pointing in the right direction. i did try to unplug the MAF & it ran even worse. Good idea for the timing, I will check that out also.