1989 T/A 305 TPI...Set IAC and then set TPS (with and without ETS unplugged) at .540. New plugs, cap, wires,cleaned IAC and throttle body , Adjusted fuel reg. to 41, new fuel pump.... Idles at 900 and refuses to start when cold unles you give it two tries ( does not matter how long you held key first time, will not start till you let go of key and start again!!!)
Any suggestions? This is an automatic and was set with car in gear.
Car runs fine otherwise.
Thanks

 

Unless you have installed a different eprom (with a higher idle speed) or mis-adjusted the IAC; I would look for a vacuum leak.

 

vacuum leak, MAF power relay? a scanner could
tell the fuel condition or pass key alert.
you might do a voltage drop test during carnking.
excessive starter draw disabling the computer
voltage?
some hints..
airdeano

 

hey I have a question about IAC. Ok I set that and tps and everything is all good for about a week. Then its like the computer resets it self or some crap cause I gotta reset my iac.

 

Checked all areas for vacuum leak...no leaks.
Do I have to diconnect the vac line on the AFPR before I adjust it? I've tried it both ways. Still idles 950-1000. Bought car used w/high milage...only last thought is that chip was changed,how do I tell?
Any other suggestions greatly accepted!!

 

Anyone have any other suggestions...this is driving me crazy...???

 

How did you adjust your IAC? If you dont follow the procedure exactly, it wont work.

The steps are as outlined below.

· Key Off
· Attach TPS test harness
(allows multimeter to determine TPS voltage otherwise use a scanner)
· Insert Trouble code jumper
· Key On
· Wait 30 seconds (for IAC pintle to retract)
· Unplug idle air valve harness
· Key Off
· Remove jumper
· Key On, Start Engine
· Adjust Idle screw to correct rpm (650-700)
· Adjust TPS to .54 v using ohmmeter
· Key Off
· Replace idle air valve harness
· Remove TPS test harness

If you dont do it this way, the computer will just try to put it back where it had it in the first place.

------------------
Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] My 86 IROC 305 TPI Page (406 build in progress)

ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.362 @ 88.238 mph (uncorrected, headers, no NOS)
<><

 

Hook a scan tool up to see what the idle being read by the computer is as well as the commanded idle.

 

Try tightening your runner and throttle body bolts just for the hell of it. You never know.

Bugs

[This message has been edited by Bugsbunny (edited October 23, 2001).]

 

Desert86Roc: Is it necessary to disconnect ETS( ignition timing plug) ? in this process?

 

You only need to disconnect the EST bypass if you're setting timing.