Why does my '74 1.8 sometimes run so RICH?, After a bit of driving, it won't idle Options

[drdstny]

Hello many kindred,

So I drive my 914 every day, about 60 miles per day to be exact. Almost immediately, I noticed that (this is so hard to believe I'm having trouble posting) if the left engine heater hose comes off the heater blower, the car won't idle and will stall unless I keep the R's up above 2K.

So...I fixed that with some Tape.

Before I Taped it to the blower, it was predictable: if the car suddenly started running rough, rich, with smoke pouring out of it, then I knew I needed to put the hose back on.

Since I "repaired" the hose, now it's less certain. About halfway to work, once I hit traffic and have to stop-n-go, it idles rough. VERY rough, and I need to side-step the gas to keep the engine from stalling. Smoke will come pouring out of the tailpipe, my eyes water, can't breathe, lose faith in humanity, diet goes awry, idle won't calm down...you get the idea.

Seems like it only does this after about half an hour of driving, and USUALLY letting it sit for a couple hours will make the problem go away. Not always, but usually.

The first thing I tried was changing both seals (O-ring and gasket) on the oil cap (recall it's a 1.8), but that made zero difference.

So...anybody have any idea what's wrong? Just as good: anybody have a list of things I can test or replace until the problem is fixed?

This is a serious issue, and the last two tanks of gas have been sub-20MPG so I'd really appreciate the help. I'll send something nice to the person who gets me out of this jamb.

Thanks!

[billswim]

I've got a couple but you need to see how many pins are on the plug. Some have 6 some have 7 (I think). Your problem doesn't sound like the air flow meter to me though. It doesn't make sense that it takes almost 30 minutes of driving. A stuck AFM should be the same all the time. your mixture would right at only one perfect throttle position. I've recently had trouble with the 1.8 fuel pressure regulators. Test the system to see what running pressure you have at idle and at part throttle. I forget the #'s but around 29 psi at idle and a few lbs more at part throttle. The temp sensor is also a prime candidate. If its grounding out, it would make the car go lean, not rich. If it was stuck with high resisitance (sp?) the car would think it was always cold and would put too much fuel in but not so much that your eyes watered. Also the 1.8s are SUPER sensitive to vacum leaks and if you have recently fixed a vacum leak, and the system was adjusted for the leak then the car would run too rich. Don't just throw parts at it. It'll cost way too much.