fast idle

randyc123 · 06-13-2009, 12:54 AM

I have a1990 gmc tracker with a 1.6 8 valve engine.when I start it up when cold it idles at any where from 2000 to 2500 rpm and will stay there until it is warm .I feel this idle is way to high and was wondering if there is an adjustment or if there is something wrong .
thanx Randy

komobu · 06-13-2009, 07:01 AM

There is a fast idle screw adjustment...It is on the throttle body but can be hard to spot on first glance. You really have to look for it.

onestoptakeaway · 06-19-2009, 12:12 AM

Quite similar to my question back in January http://www.suzuki-forums.com/suzuki-...-4dr-auto.html

jtgh · 06-20-2009, 02:08 PM

that screw is hot fast idle , he said cold fast idler is wrong.

if you mess that , then hot idle will be too low. way too low!

on the 90 (and 89)

check ign. timing first. ( if off ?, idle will never be correct)
then make sure Dash pot cold fast idle is dropping off after 3 to 30seconds, (varies by temperature)?

nO. then dash pot is bad. ask how to fix.
if you are not liking dash pot idle speed , then calibrate it , it has its own adjustment. ask.
YEs (it retracts), then
you have an air leak ( but no if hot idle is ok) or the IAC is bad (rare) or the ISC is bad, common.

you need to tell the full story.

cold 3-30secons, idle speed.?
then after 30 seconds what is it.?
then when hot (does it really get hot?) what is idle. Hot running idle what is it.

motor coolant thermostat must go to 180F (82c) or idle will never be correct.

idle is the LAST thing that works on EFI .

Electonic fuel injected cars.

bad ECU, bad ISC, tbelt slipped. s,someone, adjusted all things wrong, timing set with out placing the freeze jumper, weak cylinder.
this list is short, the long list will fill the server.

cheers.