Tbobby

Alright I'm back to trying to figure out why my gto is stalling as soon as coolant temp hits 190 degrees. The car will run fine idle rev all good. until it hits 190 and it dies suddenly fans kick on for a split second then they turn off too, wait for coolant temp to drop down below 190 it will start right up. Ive watched the volts on the battery when it dies and nothing crazy there. Ive unhooked both fans and still same deal. I also unhooked the temp sensor and tried that with the same outcome. I tried putting my old tune back in it again just to make sure nothing happened last time i flashed it and that didnt change anything either. I also replaced the crank sensor too. This all started out of nowhere the car was on the dyno end of last year I put it away its sat for a few months but still being started a couple times over winter then first time taking it out this started. The car is a procharged 376 tuned on speed density.

G Atsma

Crazy thought- A crack on a circuit in the CPU that "parts" right at 190*... closes under that.... my .02... disregard if too off the wall....

LLLosingit

iTrader: (4)

I'm not up on tuning the stock computer but could you have the temp set to enter closed loop at 190* then looking for your MAF that's longer there since you said you're running a speed density tune.

spy2520

iTrader: (3)

Funny you say that. I just recently fixed an issue with a broken wire in the fuse box that had continuity until it heated up. It was stopping the headlights from working. Can't say whether a similar issue exists for the OP though.

Tbobby

Well it turns out the cooling fan is causing it. After someone told me I could turn the fans on manually with hp tuners while its running as soon as i turn fan 1 on it stalls. The fan will come on and stay going though but the car wont run. I can turn that one off, start it and turn fan 2 on and the car will still run fine so i know fan 1 is my problem. I've unplugged the fans and I've pulled the relays but neither did anything so I'm not real sure where in the circuit I'm getting the problem.

computerz

I believe there are 3 relays for the 2 fans. Maybe try pulling all 3? But note where they came from, not sure if they are different. And obviously don't let your engine get too hot without fans!

2xLS1

iTrader: (25)

Apparently 04 GTO E-fans are not the same as the 3 relay/both run low speed/both run high speed design GM usually uses with dual fans. Looks like the BCM is involved too.

jimmyblue

iTrader: (11)

Might look at the fans' ground return and what may be
sharing it, vs PCM ref gnd. Sensors could be getting
jacked. Likewise see if fans are just sagging IGN (or a
branch of, check voltage across fans vs voltage across
battery vs voltage across alternator).

A marginal idle situation might just not deal well with
step electrical load. See anything like an idle dip when
you turn on the headlights? Or just apply a poor-boy
20 amp load across the fuse box input stud and
nearest sheet metal ground stud?

Tbobby

Thanks for the help guys its taken me awhile to get back to messing with it. I know the BCM is involved on the low speed fan which makes me wonder if the BCM could be where my problem is.

I thought the same about just pulling to much power when they start causing it but ive checked voltage at the battery atleast and i dont see a huge drop other then just the car dying and i figured it would take just as much draw to start the high speed fans and it will kick them on with no problems.