Quote:
Originally Posted by Ccmano
So the idle speed on the Z is a bit high by about 2-300 rpm. I've gone after potential vacuum leaks and I think I have addressed all of them. The IAC readings on my Tech1 are 0 at idle, indicating there is still an issue. In researching this I came accross Haibecks presentation on the issue. One of the items on his list is the IAC stepper motor. His test is to remove the motor, remove the o-ring and reinsert it into the throttle body. He says there should be a .020 gap between the TB and the motor body. Indicating that the pintle of the motor is seated against the TB, sealing it up properly.
http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf
I checked the old one and found I had zero gap. So I picked up new one today from Summit. Even made sure the part numbers cross referenced. Darned if it doesn't do the exact same thing. No gap!
Has anyone run accross this? Does the 90' have a different IAC motor?
TIA
H
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Not to say I have the solution to your idle problem, but this is what I ended up doing...
I did not actually check the gap this particular time when I installed the IAC. I did however make sure that the pintle was under an inch from the base by depressing it by hand as shown in the pic as per FSM instructions below.
the instructions as per FSM...
"Tighten to 27 lb. in.
Reset the IAC valve pintle position
A. Depress accelerator pedal slightly
B. Start and run engine for five seconds
C. Turn ignition "OFF" for ten seconds
D. Restart engine and check for proper idle operation"
Also as has been mentioned, you would need to adjust your min-air screw and turn it counter clock wise to bring up your IAC counts. And you only turn that screw one "hair" at a time. Just a very, very slight touch is all that is needed. Then blip the throttle, and let the idle settle down and then check and reset your TPS if needed, blip the throttle again and let the idle settle down. You may have to repeat this procedure to get your readings within range. I would recommend a test drive after each of the two adjustments with your Tech 1 connected.
And of course these adjustments are made with the engine fully warmed up and in Closed Loop, which you probably know.
If your idle is still the 200-300 rpm's higher that you mentioned, there you most likely have another issue that needs to be determined and addressed.
BTW, what is your idle reading at now???
Good luck, hope you get everything corrected....
the pintle after retraction...I know the tape measure is not flush against the base, but placed it there to give you an idea....the pintle is now under one inch when adjusting the tape measure for the difference...
