High Idle again! WTF Grand Prix Owners Step in

[firemandan1700]

About two weeks ago my car was rough to start it and it was running high idle all the time. So I thought it was the IAC sensor, replaced that, no luck. But I noticed my fans were not kicking on and my ran reeeeally hot, so I said screw it and replaced it t-stat and the ECT sensor.

Well replacing both fixed it. But now its doing it again two weeks later! Do you think its the ECT sensor going out or is the pcm bad and shorting out the ECT sensor? I Looked at the wire and appears to be fine. But I know failures of ECT sensors are from excessive vibrations and excessive heat... Which the ECT sensor is probably no more than 2" away from the tog crossover pipe. But why is it doing this now when I have had my headers on since End of March?

Any help is appreciated. Im kind of running out of paitents!

Thanks!

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[bikrboy128]

easiest way to figure out if it's the ECT sensor is check in your scan tool.
cold start the engine and watch the temp as the engine warms up. if the temp doesnt move then you have a bad ect sensor.
another thing you could do is unplug the sensor all together. the PCM should command the fans on and the temp gauge on the dash should read all the way hot.

my ECT got screwed up with my headers as well. one of the crossover flanges was too close to the sensor.

 

[firemandan1700]

But my headers have been on for over 5 months though. And now its going on its 2nd ect sensor? seems like it might be something else.

How did you solve this. Did you just rotate your flange?

 

[bikrboy128]

yea, i rotated my flange away and got a new ECT sensor.

maybe wrap the sensor in header wrap? i know buick does it for their park ave. right out of the factory.

 

[firemandan1700]

I got some heat wrap and a new ect sensor. I was also told on another board to see if I returned my car to stock-ish like settings to see if that fixes it. If not im going to change the part, if it fails again, im going to order a new pcm, if that fail im taking the walk of shame to the stealership....

Cause then im am just out of ideas.

 

[bikrboy128]

if you werent so far away i would help you out.

dealership=bad idea. they will blame the failure on your headers.

 

[02BlueGT]

Yeah, Like my failed MAF was a result of my ZZP pcm.....Fuck Carmax

 

[firemandan1700]

if you werent so far away i would help you out.

dealership=bad idea. they will blame the failure on your headers.

Im down for a trip to ge

 

[bikrboy128]

shoot me a PM when you want to head here then. i will be glad to help.

 

[firemandan1700]

Im gonna make the many attempts of figuring out what is wrong with my car, utimately just short of changing out the pcm.

Wish me luck

 

[02BlueGT]

Whats the IAC?, how about the LTFT at idle....Is it a smooth high idle or a surggey(sp?) one?

 

[firemandan1700]

Well I had made a post at clubgp and someone had mad mention that my tune might have gone bad. I was told to reflash it with a stockish like bin and go from there. Well that seem to be the case. I flashed it with a stock bin, but i included my 3.29 tranny settings, added .25% to the maf at 7000hrz on up, and added 1 degree across the timing table, and well what do you know, it started rough and had a high idle for a bit, but after driving it for a few times and starting and stoping the high idle went away. Go figure lol.

But now i gotta tune like crazy if i want to go to cordova in october. lol. I threw on the 3.8 pulley for this stock tune.

http://www.scandepot.net/viewscan.php?pk=5321

This was taken yesterday in the middle of the day, so like 85+ degrees. I am kinda confused about this, if you look, the obvious things is that i have very minimal kr. less than 1*. But my ltfts are positive, and o2 readings are 980+

I know the o2 sensor had the insulation melted off, because the tranny people who installed the tranny didnt tie the wire back up and the insulation melted. But i was thinking on replacing the o2 sensor just to see if that would make the difference, just incase the sensor took a crap due to the wire melting. Plus the car has 91k+ miles on it so why not.

So what do you think?