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Still fighting the Idle; Won't Idle
Topic Started: Sep 23 2011, 11:21 PM (388 Views)
Geeeo
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Geeeo
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Ok been reading through pages of forum posts on Idle, most on too high of an Idle, not me mine wont Idle, I found one article that made real sense. The TPS adjustment procedure, the "book" says .98V-1.02V with 3.5mm gap between the throttle body Idle hard stop screw and the throttle linkage. But what if the PO has maladjusted the Idle speed screws? What is a good base setting?
The article said that setting the throttle plates dead closed and set the TPS at 05V so that the computer knows that the throttle is closed and it needs to control Idle, does this sound correct?
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Bad Bent
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Facetious Educated Donkey

My PO did in fact screw with the screws.

The factory set Allen screw should not have been tampered with. The throttle plate (TP) is adjusted so it stops sticking. Any more and the idle raises with more air let in.

So first you have proper throttle cable tension and play, and you adjust the throttle plate so it does not stick. This can go back and forth a little. The TP should let a very small amount of air into the TB. My was sticking so I screwed the Allen screw in a little and drove down the road, stopped if it stuck and drove again, repeat as necessary. I adjusted the idle speed screw and then the TPS. If your Allen screw is screwed in so more than 1/8" of the screw extends below the plate then the TP may be open too far.
So my procedure was TP, idle, TPS and repeat as necessary and recheck cable tension. Idle should be at 850, I think mine is around 900. BUT it has stabilized since changing the O2 sensor.

As I reason it, when you add throttle it first opens for more air and simultaneously rotates the TPS which signals the ECM to add fuel. The TP is slightly open or it would choke the engine. The TPS range is 1-5V so you need a "base" measurable setting and 3.5mm = 1V +/- .02 tolerance.

Hope that helps.
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