Surge up, die out, recover idle, whistle, repeat

B

BUDXR7

Registered User
My car started this pattern of surging, near stall then recovery accompanied by something relieving with a whistle. Over and over until I get the rpms up. After driving a little while it goes away. The relief and whistle sounds like it could be associated with the bypass valve. Recent work includes 10% jackshaft + chip burned by a member here.

I'm stumped on this. Could it be associated with the pulley? The chip? Could it be vacuum leak? What is that intermittent whistle? I did some work on the induction side a while back but this symptom is a new development.

I am all ears. By the way, this site has been an excellent resource for me and I thank the members here for their input.
 
when my iac was starting to fail it would honk like a goose and then it began to whistle for a day or two and then it went out.
maby check or clean it..
 
I read in another thread the computer can learn a faulty program. I did unplug the IAC with the engine running right after installing my new chip(presumably while it was still "relearning") The engine shut off. Maybe this was the issue because I disconnected the battery today to let everything refresh and it seemed to run with out the issue afterwards... I'm thinking mercurial would be more appropriate than mercury.
 
I was gonna recommend resetting the ecu seems im a little late

if the engine stalls when you unplug the iac at a warm stable idle you need to open the set screw slightly to give it a touch more air

If all works well I wouldnt be concerned with it
 
I thought I would close this out. I realized after several months of this that the valve cover vent connected to the intake tube had fallen off. I'm thinkng this has a pretty serious impact on fuel mixture due to unmetered air. I think the computer compensated for a lean condition so when I put it back on it went rich. Not sure if this is how the adaptability of the EEC iv works but I reset the computer and it's running like a dream now. No iac issues any more. No stutter, stall or recover anymore.
 
BUDXR7 said:
I thought I would close this out. I realized after several months of this that the valve cover vent connected to the intake tube had fallen off. I'm thinkng this has a pretty serious impact on fuel mixture due to unmetered air. I think the computer compensated for a lean condition so when I put it back on it went rich. Not sure if this is how the adaptability of the EEC iv works but I reset the computer and it's running like a dream now. No iac issues any more. No stutter, stall or recover anymore.
Click to expand...

Cool. There's been a couple of times that I've removed the intake tube to put on a throttle body or whatever, and almost forgot to hook up that tube and wondered if it would have some sort of idle issues.
 
1FSTBRD said:
Cool. There's been a couple of times that I've removed the intake tube to put on a throttle body or whatever, and almost forgot to hook up that tube and wondered if it would have some sort of idle issues.
Click to expand...

Oh yeah. I drove it like this all summer I think. If the iac wasn't freaking out at idle it would just idle too high - like 850-950. Don't know what effect it had at higher rpms but there were a few times where the car just said NO and died out, this happened twice out of maybe a dozen cruises. All clear now, driving like new again.
 
You must log in or register to reply here.
Back
Top