IDLE

[Rex Ruby]

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:cheers:

[gbmidyear66]

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]

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) (mhaibeck@sbcglobal.net)) with the symptoms and see if he can make some recommendations.

Good luck,

Jim

[DaveK]

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]

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]

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.