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Very rich-Backfiring-Stalling...help with diagnosis

 
Old 06-07-2006, 07:28 PM
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Teddy952
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Default Very rich-Backfiring-Stalling...help with diagnosis

I just completed installing a new rear main seal and was ready to start the car. It started immediatly but was chuffing/coughing and barely keeping an idle. I blipped the throttle a couple of time and it seemed like the engine was going to stall but never did. There was a lot of black exhaust coming out the tail pipe. I turned it off and checked wires/hoses/tps/vacuum lines etc... and everything checked out ok. During the seal replacement I wasn't really working in the engine bay other than removing the speed sensors, disconnecting battery and a ground wire from the top of the bell housing.

I started her up again with the same results. This time I let it idle roughly for a couple of minutes and then blipped the throttle again. The engine revved fine and was running smooth. I let the car get up to temp and rolled her off the lift and started for home. I drove about 6 miles without issue at all. It was boosting fine and idled like it always did. On the highway I noticed that the sound of the turbo seemed to be much more audible and was spooling faster than before. Then it started to sputter and I noticed black smoke in my rear view mirror. I gave it more gas and it coughed more and started to backfire badly. Drivers on the highway behind me started to beep and point to my rearend indicating some kind of fire. Greeeeaaaaat. I figured that was enough and pulled over to call for a tow. While waiting I let it idle and it was running horribly rich and stalled when I gave it some gas. I tried to start it up again and the battery was dead????? Very odd.

Before I started this job the car was running great, however, it had a test pipe installed. Seeing as though I was ready for state inspection, I had to put on my old cat that had been sitting for a year. Except for a new rear seal, the cat pipe is the only thing that changed during the install. Could these symptoms be a clogged cat?? If the speed sensors were incorrect I don't think the car would even start. I barely did anywork in the engine bay so I couldn't of broke a wire or pulled a vacuum hose off.

Im not going to work on the car untill I put the test pipe on again to eliminate a clogged converter. I have an Huntly Stage 3 MAF and ARM1/ARC2 with GURU chips installed. This car has been running fantastic for years. If putting on the test pipe doesn't change anything then Im removing the ARC2 and MAF and try to bring it back to stock for trouble shooting purposes.

Anyone have any ideas

Thanks

Ted
1989 Turbo
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Old 06-07-2006, 07:35 PM
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special tool
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You have a main pipe air leak.
Check the intercooler pipe rubber boots and bypass valve fitting. Wiggle them.
Under vac, they may sometimes be okay, but positive pressure will open the leak again.
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Old 06-07-2006, 08:03 PM
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Teddy952
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So no clogged cat you think?

Ill try to get it in the garage in the next day or so for a closer inspection. Hopefully I won't have to push it.
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