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mark '87 930 mark '87 930 is offline
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Join Date: Feb 2006
Location: Toronto, Ontario
Posts: 727
I'm stumped.. (intermittent issue) O2 sensor makes a VERY rich condition

I've just reconnected a new O2 sensor into my GHL headers. After a little warming up, I took her out for a stroll... and it was acting strange the first 5 minutes, seemed like it needed to warm up. The car would not idle right, and almost died when at a stop light (idle at 200 RPM). When all that was out of the way, the car ran fine.

I stopped the car for 15 minutes.

When I started it again and went all, the first chance I got I nailed the throttle to get a good rush of boost.. but the just wanted to cough and die.. I immediately looked out the rear-view mirror and there's a big black cloud of smoke out the rear.

I try gradually pressing the throttle, and again, it bogs and just dies. It seems to be when I start to hit boost.

10 minutes into that drive, I try again, all works fine??

This whole problem started when I replaced my GHL headers last year. I heated my O2 sensor cherry red to get it out... turns out that wasn't good, so I bought a new one, and it was good for about a month.. then the issue started again. When I disconnect the O2 sensor, the problem goes away.

Some questions I have..

1.Can't be the new sensor can it? (2nd one)
2.Can it be an exhaust leak at the headers?
3.Is the O2 sensor somehow connected to the WUR, and maybe the boost signal spikes too soon, telling the WUR to dump more fuel?
4. Can it be that fuel enrichment box (that thing under the seat)? If so, how do I check it?
5.Could it be that the way I wired in the O2 sensor, that the wires are too close to the engine and the heat is causing some havoc?
5. Is the relay under the drivers seat for this.. maybe a connection?
6. Is it Ignition that is somehow conected to the O2 sensor, and it doesn't advance when the RPM's rise?
7.Could it be my throttle position switch?

I mention the exhaust leak because I think the drivers side headers seem to be pfut pfut pfut pfut pfuting... so I tightened up the exhaust bolts when I got home.
1987 930
1956 Chevy 3100
2009 Subaru Forester
2003 KX250 X2(I like my toys!!)

Last edited by mark '87 930; 03-30-2007 at 06:25 AM..
Old 03-29-2007, 05:04 PM
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