this idle thing has me perplexed!

[Datsunboy]

Well guys here is a rundown of whats been done recently. Idle is still nasty on my car. It will rarely drop below 1800rpm, and is inconsistent as far as its idle of choice.

New f/p regulator and hotwire... set to 42psi
Cleaned out IAC, checked connector for nasties.
cleaned out the throttle body (just cause i was already there)
did a decent check for vacum leaks, everything LOOKS okay, i sprayed with fi cleaner waiting for idle noise.
IAC reset
attempted TPS reset w voltmeter

The car idles smoothly at low RPMs when i can get it to stay there, but it usually will not.

Ive done that iac and tps adjustment about 15 times and CANT get the thing to be happy at idle and wot.. what gives?

Any thoughts?

Thanks - Evan

 

[FJM568]

Have you ever had the intake off??? Does your throttle body to MAF tube have any holes or cracks in it??? Is your throttle body gasket cracked or torn or even getting sucked into the turbo??? If it does, you are getting unmetered air into the engine which would cause your idle to go up...The question on the intake was about whether or not you have an intake leak into the lifter valley, which wouldn't show up with the cleaner on the topside of the motor...

Doing the IAC and TPS adjustments aren't that tricky once you know how to do it...

The IAC you really need to use some kind of scantool, and while you're at it, set the TPS with the scantool, so you set it to what the ecm "sees" and not what you read directly off of the TPS w/voltmeter...You really can't do the IAC without doing the TPS at the same time...At least that's the way I remember it...It has been awhile since I've done the adjustments...

 

[Datsunboy]

I have yet to molest my intake...

MAF pipe is in really good shape actually.

I blasted the TB flange with FI cleaner and saw no apreciable change in idle qualities. I dont think its leaking.

WHAT SHOULD MY VAC. BE AT IDLE? I pulled around 18psi at idle (which was like 1300+ rpm). I have a vac gauge i tested it with.

I really need a scantool but dont have the resources yet! Im workin on it.

Any other suggestions? I whacked my MAF with my hand and nothing happened (remembering the tap test).

I thought before my driver side header was cracked, well i dont hear much at all so i think its fine.

Overall the car runs pretty well off-idle. It stumbles ALOT sometimes but usually doestn last very long.

One other scary thing i saw, one injector had a blue collar on it and the rest didnt. I wonder if i have mismatched injectors as well....

Thanks guys - Evan