idle control problems

[iviper123]

im having problems with my idle on my 88 b2 i have replaced the idle contol unit(air bypass valve) what elese should i check? it wont go below 1500 rpms!

 

[iviper123]

any suggestions

 

[holyford86]

my 86 (with 88 EEC) does the same thing, except its about 1200 rpm in my case. I just think of it as one of the perks of having a 270k mile motor still going strong.

 

[CraigK]

iviper123

You've probably already tried this, but if not . . .

Try backing out the throttle stop screw on the throttle cable linkage thingy. This may mess up something more complicated (TPS), but hey, it might get the rpms down.

And as always with these motors, carefully check all vaccuum lines, hoses, connectors, PCV valve etc. for leaks.

CraigK

 

[Psychopete]

Try backing out the throttle stop screw on the throttle cable linkage thingy. This may mess up something more complicated (TPS), but hey, it might get the rpms down.

Don't do it! You will be off worse than you started, it might make the problem even harder to diagnose because you might be trying to find a problem that slight change added to. The PCM controls the idle, not the throttle body screw.

Do you have any slight popping in the intake at idle?

What's your fuel mileage like?

Pulled codes or CEL present?

Pete

 

[iviper123]

no problems with poping or anything, it just dosent idle down, the other day she did drop to the right idle for a second then jumped up a little than jumped up some more..


i dont know gas milage, not on the road yet

 

[IMenriched]

Check the throttle position sensor (TPS).

also make sure ALL the ports in the upper intake are free ....nothing blocking them, (carbon build up), as well as the back side of the throttle plate. & the Air Temp Sensor (ATS)

then there is the temp sensor for the computer...not the guage in the cab.

 

[BradS]

Im having the Same Problem man! its been like that since it got Warm out.