dubulup

After driving a while and turning her off, then say about 5-10 mins later starting her back up, the idle bounces for about 30 sec. then stablizes. Is this idle hunting? and TPS needs adjusting? OR is it vapor lock in the fuel lines due to heat soak? and I need a vented hood...

dubulup

don't know why this got posted twice...sorry

airborne

i've had this on occasion too, assumed heat soak. goes away once the coolant flows and temps come down for me. you too?

know what else causes idle hunting? put a bag of ice on your uim and report back...scared the bejeezes outta me!

dubulup

Do what?

FDjunkie

I've been searching for detials on the potential effects of relocating the intake air thermosensor with stock ECU.

Could it be that heat soak on uim where this sensor is mounted might be briefly causing an incorrect A/F ratio?

airborne

sorry for the mostly off topic comment. if you have the AWS still in and put a bag of ice on the UIM apparently the car won't know if its warmed up or not and the idle will hunt. Tried it at the drag strip.

Now turning the car off and using ice lowered intake temps in a hurry.

"Could it be that heat soak on uim where this sensor is mounted might be briefly causing an incorrect A/F ratio?"

Its probably something along these lines though since the problem clears up after you get back to good operating temps.

dubulup

When I say bounces, I mean like +/- 150 rpms (850-650 range), slight bouncing.

95R2-89TII Ground Zero

Talk about idle hunting....mine is hunting the whole time I drive down the road.

FDjunkie

I've been working on the attached listing (in Word 2000) of those things that normally control idle speed. It's not intended to cover all issues (spark plugs for example), but it may be helpful in understanding the effects of the major items.

For example, many have condemned the air control valve for their 3K RPM cold idle speeds, but I found that my car's thermal wax/fast idle cam settings were WAY off. So far in fact that the cam was NEVER fully releasing. I adjusted the cam/temperature setting and the hot idle speed dropped down to 400-500 RPM. I increase the idle via the bleed screw and now my cold idle speed is only 1,700-1,800 and drops within seconds to about 1,500 until the engine warms. I'm happy.

Anyway, take it for what its worth, or better yet add some things that I've missed.

spurvo

Hey FDjunkie... how about adding something about shifting into first or second from neutral? Sone folks have been experiencing idle speed and vacuum fluctuations when we shift into 1st or second. I notice there's an input for these to the ECU, but no explanation what they do. Anybody?

FDjunkie

I've read posts about this, too, but couldn't find any real details or any documentation. I didn’t find anything in the manual, but then I didn’t think about examining the ECU wiring. Has anyone ever tracked any of this down? How/why it seems to work and at what temperature(s)?