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As per the subject, the warm idle is very low and on the edge of stalling. The anti-stall process kicks in and it goes through a cycle of low idle, surge, low idle, surge etc. After switching off, and it's warm, it will start and then die.
When driving, it's hesitant when pulling away, which is a real PIA pulling out at roundabouts!
Anything "easy" I can check?
Thanks in advance!
John
My '88 S4 was doing these exact things after I did a ton of work on it waking it up from 10 yrs or so of storage (fuel system flush, replaced a bunch of parts, etc). So I did the "ICV squirt it with your favorite spray" technique and much to my amazement the issues went away. I'm calling it fixed.
I disconnected the y tube/hose connection just above #12 in the attached pic, squirted in a healthy spray of carb cleaner, let it sit, started it up, Repeated it a number of times mixed in with spraying WD40, doing the same. Took about a week to stabilize the idle, now I've got the old rock solid idle back.
I also did all the other mentioned checks (MAF, vacuum hoses, plugs, etc, plus had just installed a rebuilt LH), but didn't have any luck until I sprayed the hell out of the ICV.
And I'm not saying not to do an intake refresh, just mentioning that this simple and free method is worth trying.
My '88 S4 was doing these exact things after I did a ton of work on it waking it up from 10 yrs or so of storage (fuel system flush, replaced a bunch of parts, etc). So I did the "ICV squirt it with your favorite spray" technique and much to my amazement the issues went away. I'm calling it fixed.
I disconnected the y tube/hose connection just above #12 in the attached pic, squirted in a healthy spray of carb cleaner, let it sit, started it up, Repeated it a number of times mixed in with spraying WD40, doing the same. Took about a week to stabilize the idle, now I've got the old rock solid idle back.
I also did all the other mentioned checks (MAF, vacuum hoses, plugs, etc, plus had just installed a rebuilt LH), but didn't have any luck until I sprayed the hell out of the ICV.
And I'm not saying not to do an intake refresh, just mentioning that this simple and free method is worth trying.
I should have mentioned in case its not obvious, but you want to direct the spray into the un-numbererd hose that goes under the intake manifold leading to the ICV, not into the hose towards #13/17, and not into #11 of course. I held the hose up while spraying to make sure the fluids were getting as close to the ICV as possible.
Spent the morning spraying some carb cleaner in every hour. Just started it (eventually) and a cloud of black noxious smoke came out of the exhaust. I'm hoping that's dirt from the intake?
Anyway, it settled down to a fast cold idle, which eventually settled down to about 800 rpm. It wasn't fully warm, as I don't have time to take it out today.
I've sprayed some more carb cleaner (quite a lot!) and will leave it to sit overnight and go out tomorrow.
Should I stick with carb cleaner or introduce some WD40 too?
NOTE you should run the engine now to get that chemical out of the hoses as thats where its gonna be sitting and swelling the rubber,
possibly resulting in an intake removal due to damaged rubber hoses that have split
NOTE you should run the engine now to get that chemical out of the hoses as thats where its gonna be sitting and swelling the rubber,
possibly resulting in an intake removal due to damaged rubber hoses that have split
01-30-2021, 04:24 PM
