'81 FI Runs too rich until warmed up

[dantye]

This car was not run for many years, but my mechanic finally got it running and we have already put over 500 mi on it.

It starts easily, and will idle smooth, but seems to "gag" under any load until it has reached operating temp. I think it is "choked" too rich because there is black soot in there if you remove the black plastic air intake pipe from the metal plenum.

Runs just great once warmed up. Any pointers on where to look? Thanks

[jfrawley]

I just fixed a problem much like yours. The engine really bogged down badly until it warmed up. Tested the temperature sensor and found it to be bad. Once replaced, and the engine timed properly, it ran fine. You can test the sensor with a repair manual and any ohm meter.

Another item that might cause what you're going through is the aux air valve. It allows extra air into the plenum while the engine warms up. To test that you have to remove it from the car, but it's pretty straight forward. There might be other causes but those are two that helped mine run much better. One of our forum members, Brad Artigue, has a great download to help you troubleshoot your fuel injection system. Get it here: http://artigue.com/?page_id=3

Good luck and let us know what fixes it.

[4babycar]

I also had a similar problem. My problem was the magnetic pick-up in the distributor was gapped incorrectly. Check the clearance gap and adjust as necessary. I found mine out after testing both the Aux air valve, the temp sensor and generally pulling my hair out for almost 2 weeks. Good luck.

[majicwrench]

I would doubt it is running too rich, most FI systems bog or "gag" from being too lean. Download Brads article. Everythign in the air intake system has to be tight and airtight.
Keith

[So Cal Mark]

I agree that it probably is lean. Rich condition should cause a lope at idle and soot on the tailpipe. Gunk in the plenum is normal since the crankcase vent attaches there. If the gunk buildup is excessive, it means your motor has excessive blowby

[dantye]

Thanks to all for the great tips!

I'm more than 500 miles from the car, on vacation, but will start digging into it when I return next week.

I agree that it probably is lean. Rich condition should cause a lope at idle and soot on the tailpipe. Gunk in the plenum is normal since the crankcase vent attaches there. If the gunk buildup is excessive, it means your motor has excessive blowby