Just got home, and GTPs acting up

[john99gtp]

Wow this turned out to be long, sorry.......

 

 

 

Just got back from Georgia, so Im a little sad to begin with

 

 

Get to my grandparents house, hang around for a bit, help my granddad with the garage building, etc. This is where I also sat the GTP for my vacation.

 

Went to go drive it home, started it up, and right away I noticed something was wrong. At first, I was thinking because it had sat all week, but my granddad told me he ran it yesterday just fine, to and from his work. Let it sit some more, RPMs crept up...and up...and up

 

They hit 2500, in PARK! Not to mention i could smell the exhaust, it smelled like it was running PIG rich (like i said, chalked it up to not being run for a bit). Then my SES came on...great!!! What a way to end the day. Using my Aeroforce scanner (that thing rocks) pulled the code..P0118 - Engine Coolant Temperature Circuit High Input....hmmm

 

so using the gauge, i goto ECT temp......-38*F, WTF, that explains why it was running so high of idle, it was trying to warm up. I shut the car off, looked up the code, and decided not to drive it home. I went back out after finding the meaning of the code, and looked at the sensor, looked perfectly ok, wiggled it a bit (burned the tip of finger, damn those headers get hot fast) then restarted. Idled stayed around 1000, but ECT on the scan gauge was still reading -38. :sigh: I let it sit for the hell of it, and the gauge on my dash IS GOING UP!!! it went past 160 and went to just under 180. this is the confusing part, how can the gauge on the dash read one thing and the computer gauge read another i think it may be the computer, so i drove my granddads truck home, and will bring my stock PCM back down with me and try that.

 

If anyone has any other ideas, please let me know. Im pointing to PCM, since the dash reads it correct.

 

One weird theory i think of is that rain might have gotten inside the computer or something. Thursday they said it poured, all day, and with the Wizair system, I was thinking maybe some water got in and messed with it, but i dont see how thats physically possible (especially since my granddad drove it friday)

 

Thanks for letting me rant, I should go back down to Georgia

 

 

John

[sl3196]

I doubt water got into the intake. Hmm weird though.

[mfewtrail]

Engine coolant temperature sensor is dead. I've seen a lot of them die and read really low temps, which in turn causes what you're experiencing(extreme rich mixture & high idle). As far as the gauge in the car goes, they typically are operated off of a seperate coolant temperature sensor that's only function is to relay information to run the temperature gauge in the cluster. If you have a DVOM, you can probe the ECT for resistance and then compare your reading to a temperature/resistance chart in your techline info.

[PeNZ]

He is right, there is separate gauges. New ones are fairly cheap.

[birdman]

i just got one for my 3.4 for around 8 dollars, easy to install just put gasket maker stuff on the threads and thats it.

[john99gtp]

FWIW, there is 1 sensor for both the PCM and dash.

 

 

and now using magic, i shall post a link to a schematic: http://jbarbieri.net:9001/servlets/TifToGif?pic=352429

 

 

ok, it appears that doesnt work, but i have a trick

 

go here first: http://jbarbieri.net:9001/servlets/Home

then load the pic: http://jbarbieri.net:9001/servlets/TifToGif?pic=352429

 

 

that should allow you to view the schematic

 

 

 

 

if that doesnt work....ummm...sorry?

[john99gtp]

ok so i ohm'd it out, and going by that schematic:

 

a > 12 is .01ohms

b > 26 is .01ohms

 

 

this cancels out the possibility that a mouse chewed my wires

 

 

looks like its pointing right to the ECT sensor itself. Thats gonna be a bitch to change, its right next to the crossover, and the hole is pointing downwards, meaning its gonna leak coolant like crazy, not to mention its sunday and im going to be lucky if i find a parts store open.

 

if anyone has any other ideas please let me know before i try ripping out the sensor.

 

thanks

 

john

[john99gtp]

ok so, another question

 

had my cousin sit in the car and watch the gauge. I wiggled the connection going to the ECT sensor, and it was jumping from 68 (yes!) to -38 (boo)

 

 

could that be the wiring harness? im hoping so, since that should be easier to replace. im going to try and tighten the contacts on the plug to see if that helps

 

 

right now i got it sauing 80 (warmed the car up a bit) but im afraid that if i start driving it might go back to -38. im going to try and ziptie it back, but its getting damn close to the headers so im worried about melting it

 

anyone have a spare harness