IDLE - ZR-1 Net Registry Forums

Rex Ruby · 09-18-2010

FYI, I've had an idle issue since I bought my ZR1.
Sometimes when I come to a stop it wants to idle at about 1200.
Usually I can "kick" it down to about 700 - 800.
When the AC is on its hardly a problem.
Read on this forum that the K&N air filter maybe to blame which it what I had.
I put an OEM air filter in a few weeks ago and the problem has gone about 70% away.

FWIW

gbmidyear66 · 09-20-2010

I had similar issues. Taking the filter right out didin;t resolve my high idle issues.

I finally had a custom PROM burned for me - idle behaviour is now 100% improved.

QB93Z · 09-20-2010

John,

I see that you have a Haibeck chip installed.

I recommend that you give Marc a call or email him (mailto:mhaibeck@sbcglobal.net) with the symptoms and see if he can make some recommendations.

Good luck,

Jim

DaveK · 09-20-2010

I used to have this problem occasionally with the standard chip, but Marc's chip eliminated it altogether. I also have the K&N filter.

Aurora40 · 09-20-2010

Do you have access to a scan tool?

I believe the '90 calibration problem (though someone correct me if I am mistaken) is that it doesn't command a lower idle when you stop. So in a scan tool, you should be able to see the desired idle and the idle air counts. Presumably (my car came with the updated cal already) you would see a commanded idle of 1200 or so, and many idle air counts.

If you see a commanded idle of 650 or so, and zero idle air counts, either your throttle body is sticking, your IAC has some problem/needs to relearn, or you have some other air leak.

When you say you can "kick" it down, what do you mean? Blipping the throttle? Some other thing?

The A/C on puts a big load on the motor, to where the air the engine needs may surpass any air leak, so this may be why you don't have the problem then. I want to say kicking the A/C on adds like 10-20 steps to the IAC, which is kind of a lot.

Edit: nevermind on the cal thing, you have '94. That was a '90 only issue I believe. Presumably it would just be an occasional air leak from a sticking TB, a bad/unlearned IAC, or some air leak elsewhere.

Belsy · 09-23-2010

Look over your entire PCV system & replace valves if dirty? Cracked hoses or sloppy connections? Wire tie @ valves if loose & seal all w/hair spray. The system can give goofy symtoms.

09-18-2010	#1
Rex Ruby Join Date: Feb 2005 Location: Springfield, PA Posts: 372	IDLE FYI, I've had an idle issue since I bought my ZR1. Sometimes when I come to a stop it wants to idle at about 1200. Usually I can "kick" it down to about 700 - 800. When the AC is on its hardly a problem. Read on this forum that the K&N air filter maybe to blame which it what I had. I put an OEM air filter in a few weeks ago and the problem has gone about 70% away. FWIW __________________ John Porter '93 Ruby Coupe ZF6 - Muffler eliminators, Blink Blink kit and Polished ZR1 Wheels * PA Plate: OBSSSN '06 LeMans Blue C6 Coupe - Corsa exhaust * PA Plate: OBSSSV ZR1 Net Registry Founding Member #153 40th Anniversary Registry Member NCM Family Membership #8116 Corvette Forum NE Events Coordinator Delco Cruisers Board of Directors SAVE THE WAVE!

09-20-2010	#2
gbmidyear66 Join Date: Feb 2008 Location: Vancouver, BC Posts: 252	Re: IDLE I had similar issues. Taking the filter right out didin;t resolve my high idle issues. I finally had a custom PROM burned for me - idle behaviour is now 100% improved. __________________ [SIGPIC][/SIGPIC] __________________ 1990 Corvette ZR-1 #2824 4.10's, Custom PROM, Flowmaster, Top End Port NCRS BC Chapter

09-20-2010	#3
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,687	Re: IDLE John, I see that you have a Haibeck chip installed. I recommend that you give Marc a call or email him (mailto:mhaibeck@sbcglobal.net) with the symptoms and see if he can make some recommendations. Good luck, Jim __________________ If it isn't fun, you aren't doing it right! 1990 Black ZR-1 - sold 1993 Quasar Blue ZR-1 1994 Competition Yellow ZR-1 1995 Dark Purple ZR-1 Maryland State Coordinator WAZOO Member

09-20-2010	#4
DaveK Join Date: Jul 2004 Location: Sudbury, Ontario. Canada Posts: 1,535	Re: IDLE I used to have this problem occasionally with the standard chip, but Marc's chip eliminated it altogether. I also have the K&N filter. __________________ 1991 #1516 Black/Black davidmkelly.com "Speed is often confused with insight." - Johan Cruijff

09-20-2010	#5
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,713	Re: IDLE Do you have access to a scan tool? I believe the '90 calibration problem (though someone correct me if I am mistaken) is that it doesn't command a lower idle when you stop. So in a scan tool, you should be able to see the desired idle and the idle air counts. Presumably (my car came with the updated cal already) you would see a commanded idle of 1200 or so, and many idle air counts. If you see a commanded idle of 650 or so, and zero idle air counts, either your throttle body is sticking, your IAC has some problem/needs to relearn, or you have some other air leak. When you say you can "kick" it down, what do you mean? Blipping the throttle? Some other thing? The A/C on puts a big load on the motor, to where the air the engine needs may surpass any air leak, so this may be why you don't have the problem then. I want to say kicking the A/C on adds like 10-20 steps to the IAC, which is kind of a lot. Edit: nevermind on the cal thing, you have '94. That was a '90 only issue I believe. Presumably it would just be an occasional air leak from a sticking TB, a bad/unlearned IAC, or some air leak elsewhere. __________________ Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img]

09-23-2010	#6
Belsy Join Date: Nov 2006 Location: DeBary , Fl. Posts: 119	Re: IDLE Look over your entire PCV system & replace valves if dirty? Cracked hoses or sloppy connections? Wire tie @ valves if loose & seal all w/hair spray. The system can give goofy symtoms. __________________ Gene in Fl. :handshak: ______________ 95 ZR-1 #399 Dunn heads X-pipe w/3" misc. mods