idle question

[jimmers]

I was setting my idle and timing on my 90 l98 today. When i unplug the est i set my timing to 6. When i plug the est back in my timing is at about 12 and the rpms go up? Is that normal? Then when i went to start my car later in in the day, it wouldnt start. After i unpluged the est the car started. What is goin on?

 

[Vettefan87]

That is normal for your timing to jump to 12 when you plug the EST wire back in, since that is the advance on the motor. How exactly did you set the idle? If you just moved the idle screw, you might end up with problems. I am not sure the proper procedure to set your idle with the TPS and the idle screw. Are you throwing any codes? I would go back and check your base timing again, as well as your TPS voltage with just the key on, and at WOT with just the key on.

 

[jimmers]

Oh so that is normal. When i changed the idle i did do the TPS voltage aswell. Im not throwing any codes. Aslong as thats normal i guess. I never knew that it did that. Thanks!

 

[Vettefan87]

I don't know how anything you would have done would have caused your car not to run, unless your TPS voltage is way off. I would recheck everything you have done. Check the base timing, and the TPS voltage. I think the full advance is around 38 degrees that the motor see's by the way. Hopefully someone else might be able to shed some light on this problem. As for me I am not sure.

 

[WaveDoggie]

Hopefully you only adjusted the TPS-IF you 'adjusted' the idle, you have MISadjusted the throttle body minimum air setting. This can and will cause stalling and driveability problems. Consult your Haynes manual for the procedure.