Nik's problem of the day "Hunting idle!"

nixter · 05-28-2005, 02:13 PM

I'm trying really hard to keep it together people. I've dumped a lot of money into this thing lately and I seem to have a brand new problem every other day.

Ran fine last night although it was a little slow to start up. The RMP crawled up to 1k rather than the usual reassuring "jump" it normally has when starting. Same thing this morning. Drove my girl home which took about 20 min. Headed to the gym after and halfway there the idle starts dipping to almost nothing and jumping back up to 1k or so. I think this is called hunting. Anyhow I limped it to the gym and hoped that maybe something due to our really hot weather today caused it and an hour of cooling would at least allow me to get home. No beans, wouldn't even start afterwards. I also noticed that when the hunting started, the cabin reaked of fuel. I also noticed that prior to the hunting I was getting some muffler "crackling" which I haven't had lately since it was last tuned.

Vaccum leak?

And just to be thurough, I've noticed in the last few days that there's this strange sound from the muffler when letting off the gas between shifts that almost sound like a turbo wastegate valve. Something like a short, wet "hiss"

It's been to the mechanic so many times lately that it's not going to be anything obvious I don't think.

Thanks guys,

Nik

bigchillcar · bigchillcar's Garage

first guesses would be a vacuum leak or faulty lamda sensor (if your '80 has lambda). you can try to diagnose the vacuum leak yourself by spraying car cleaner around the air intake, hoses, etc. if the volatile gas finds a leak, it will cause an immediate increase in idle speed due to the increase in performance, etc. better to perform this test on a cooler rather than hotter engine just to be careful. you may get lucky and find simply a split hose, or loose airbox cover. good luck.
ryan

nixter · 05-30-2005, 07:18 PM

Woa, just tried to start her up and she did ok for about 20 seconds then the hunting started again. I shut her off and noticed a strange hissing noise that lasted about a second. I went to the back and looked in the bay then under the car... HUGE GAS PUDDLE!

Obviously this is my problem but the last couple times I had it running with the hunting problem there was nothing leaking out the bottom, I checked. Something must have come loose, causing the hunting, and now fully broken free, causing the leak. The dripping seemed to be coming from about 1.5 feet from the back of the car.

I don't think the leak is in the main engine bay area as don't really smell gas in there but it reaks in the cabin.

Any ideas where the leak could be from?

Nik.

Paulporsche · 05-30-2005, 07:45 PM

Yikes! Be careful Nick.

Does the gas seem to be coming from the driver's side rear? It may be your fuel accumulator. Or it could be any fuel line. The hiss may have been a release of pressure, or maybe just the spray of fuel on the pavement. Are any of your plugs wet? You have to hunt this down. Don't use an open flame and keep a fire extinguisher handy.

nixter · 07:59 PM

Thanks Paul, not risking it. Towing it to the wrench. He owes me one anyways.

Actually I think the hiss may have been from the gas dripping on something hot! Hard to tell where exactly it was coming from as it looked as though it was running around a few different areas b4 it dripped out the bottom. I only had the car on for less than a minute thank god. The leak stopped as soon as the car was shut off.

3rd time I've had it towed in less than a month. Only 1 freebie left on the BCAA for the year.

Nik.

edit: No open flame? So I shouldn't go searching for the leak with my Zippo?