Idle too fast - ZR-1 Net Registry Forums

fastcw · 01-17-2008

I have a '91 with 13,400 miles. It has always been a little slow to idle down to 800-900 rpm since I bought it with 11,400 miles on it.

Now the idle is very slow to come down to 1000-1100, and while I'm sitting at idle, will jump back to up as high as 1500-2000 for a second before dropping back to 1100 or so. Rarelly goes down below 1100 now.

Any ideas?

Sgreg · 01-17-2008

GM has a replacement prom which brings idle down. Don't have # but someone will.

tomtom72 · 01-17-2008

I don't know the # but over at the netreg site is all the info ya need!

01-17-2008

16193416 BTW, discontinued.

tccrab · 01-17-2008

My '90 used to idle a little high, I bought a Haibec chip and it's been
perfect since.
There is a difference between stopped idle and idling as the car is moving.
When you're rolling up to the stoplight it will idle at around 850 or so, when the MPH goes to 0 the idle goes to 650 and stays there.
That being said, a prom may help you and maybe not if you've got a big vacuum leak.
A very large vacuum leak will cause your idle to be high, have you done any leak checking?

Gunny · 01-18-2008

Quote:

Originally Posted by tccrab

A very large vacuum leak will cause your idle to be high, have you done any leak checking?

I agree

01-17-2008	#1
fastcw Join Date: Nov 2006 Location: Near San Antonio, TX Posts: 7	Idle too fast I have a '91 with 13,400 miles. It has always been a little slow to idle down to 800-900 rpm since I bought it with 11,400 miles on it. Now the idle is very slow to come down to 1000-1100, and while I'm sitting at idle, will jump back to up as high as 1500-2000 for a second before dropping back to 1100 or so. Rarelly goes down below 1100 now. Any ideas?

01-17-2008	#2
Sgreg Join Date: Aug 2006 Location: Texas Posts: 518	Re: Idle too fast GM has a replacement prom which brings idle down. Don't have # but someone will. __________________ 1991 ZR-1, Black, Black, # 541

01-17-2008	#3
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Idle too fast I don't know the # but over at the netreg site is all the info ya need! __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

01-17-2008	#4
Jeffvette Guest Posts: n/a	Re: Idle too fast 16193416 BTW, discontinued.

01-17-2008	#5
tccrab Join Date: Oct 2004 Location: Folsom CA Posts: 1,655	Re: Idle too fast My '90 used to idle a little high, I bought a Haibec chip and it's been perfect since. There is a difference between stopped idle and idling as the car is moving. When you're rolling up to the stoplight it will idle at around 850 or so, when the MPH goes to 0 the idle goes to 650 and stays there. That being said, a prom may help you and maybe not if you've got a big vacuum leak. A very large vacuum leak will cause your idle to be high, have you done any leak checking? __________________ TomC '90ZR1 #792 Honorary Pirate [B]If it ain't FUN, you're doing something terribly WRONG. [/B]