Setting The Idle On A Gn

[COPO TOM]

I have been trying to set the idle on my GN by going by the factory manual. But after re-connecting the wiring harness to the IAC, (and driving the car) the idle goes to 1000 rpm in park and in gear. The only way I have been able to set my idle is by using a scan tool (OTC 4000E ) and going by the IAC counts. Now set a 32 IAC counts, which equals about 650-700 rpm idle in gear or park. TPS set at .48 closed and 4.70 WOT. Why does my car always try to maintain the same idle speed in park as when I have it in gear? Scan tool shows that PARK on/off is working. I have tried two IAC valve's and tested the MAP sensor. How is everyone else setting their idle? Thanks!

 

[mybuick]

look for vacuum leaks. how to set sensor is turn idle screw in and let idle stablize then set tps to .45 then shut off engine back out screw then start again get the counts down to 20.

 

[COPO TOM]

I had the IAC counts down to 19-20, but the car idled much higher (900 rpm). Are you doing this with the IAC connected or not? Thanks.

 

[mybuick]

connected

 

[Jerryl]

....... TPS set at .48 closed and 4.70 WOT.

Is the TPS setting you listed at idle or engine off?
Seems too high either way.

Idle rpm is controlled by the chip.

 

[COPO TOM]

TPS idle was set with engine off. Factory manual calls for .55 + or - .08. But in the past I had always set my at .42, but was trying to set it by the factory manual, hoping for a little better idle, and my car surges when I am driving it at a steady speed like 45, and I am not under a load. Thanks

 

[COPO TOM]

OH!, I did change out the chips, but it made no difference.

 

[TurboJim]

ITPS set at .48 closed and 4.70 WOT. Why does my car always try to maintain the same idle speed in park as when I have it in gear? Scan tool shows that PARK on/off is working. I have tried two IAC valve's and tested the MAP sensor. How is everyone else setting their idle? Thanks!

Get TPS under .46 and your 1000rpm idle will go away.

 

[scottyb]

Get TPS under .46 and your 1000rpm idle will go away.

yep. Get the tps to .40 - .42 and you'll be golden! Don't worry about the WOT TPS, you're WELL over the threshold.


www.vortexbuicks-etc.com is a great place for basics in TPS/IAC, etc

 

[COPO TOM]

I'll try setting it like the manual says, but I'll set the TPS to .42, first thing in the morning. Thanks

 

[Ormand]

Don't know what manual you are reading. My shop manual (page 6E3-C2-11)gives this instruction for setting min idle:
Adjust TPS to:
-.50-.59 volts 3.0L
-.36-.44 volts 3.8L

So, IF you have the 3.8 in your Buick, you should be somewhere around 0.40 to 0.42.

 

[COPO TOM]

Ormand is right, I was on the page for 3.0 engines. But I had read an article in which one man said he had set over a hundred turbo Buick's TPS at .50, and what I was reading from the manual fit.
Anyway, I got the car adjusted today. Ended up setting the TPS to .42. Which was what I had it set at before. But this time I have the set screw turned in futher, which opened the throttle plate more. Car seem to run better now. Thanks