Thread: Need help to figure out why my gtp stalls in closed loop. new job need car asap.

ok, i have a 98 gtp,i did the lim gaskets 1 year ago.as of about a month ago the car stalls almost instantly in closed loop and seems a bit rough in open loop "car has suddenly developed several exhaust leaks". this happened after the car overheated on the highway and i found the TB gasket leaking which i believe warped prematurely due to faulty pcv. i had to use what i had in order to get the car home, so i made an RTV TB gasket and put rtv where there should be a plastic oring in the pcv. Car ran great until i was 2 blocks from home and seeming hydrolocked "stalled for the first time". so next day i get it home and put a real tb gasket and o ring/pcv valve in. after that, as soon as it goes into closed loop it wants to bog/stall out, you can fight it for a minute and restart it once or twice but eventually it will not restart. it doesnt seem to sputter out, the rpms will just drop straight to 0 as if the pcm is just cutting out. although the tb gasket, pcv oring should be unrelated to a closed loop stalling issue, i find it very ironic that ever since i attempted the road side fix with rtv, the car stalls EVERY time its gone into closed loop since then, even after fixing it right.

could the rtv have destroyed my maf or maybe even o2 sensors and cause this?

could belt dressing have caked my crank sensor and cause a bad reading?

could i have cracked a head when it overheated? or bent a valve hydrolocking?

could i have possibly warped a plenum or lim gasket?

could the exhaust leaks cause this significant of a stalling problem?

Could my ICM have gone bad?

cracked egr tube?

Could a worn lower motor mount cause the angle of the driveline to be so far off the motor stalls to prevent damage?--- i read this somewhere but i dont believe it. lol

Anything else i could have overlooked?

Originally Posted by BillBoost37

I don't see anything with closed loop here. Skipping past that let's diagnose.

Pretty sure this is your problem.
http://www.grandprixforums.net/showt...hlight=failure

Likely instead of it all gushing at once, you had a pinhole that allowed enough coolant to get past w/o hydrolocking. Let's not confuse stalling with hydrolocking. Hydrolocking is when fluid fills a cylinder and the engine can not be turned over because it can't compress the liquid enough. Also.. not sure what you are doing with the quotes around things like "suddenly developed exhaust leaks" etc etc. If you are trying to make a point, it's not coming across...please reword so we can be on the same page and help you better.

Pull the plugs.. I'm betting you find some wet ones that don't smell like fuel.

Bill, Thank you for taking the time to read/reply my post. Please excuse my vagueness, my original post was way too long so i had to cut alot out in order to keep it reasonably condensed. Let me try to elaborate a bit. I am fully aware of the difference between hydrolocking and stalling, right after the road side repair when it stalled the first time i immediately attempted to crank it over and for a brief moment the motor would not turn over at all, you could hear the bendix engage and see all the lights in the car dim excessively. i tried to crank it again and it turned over very slow and seemingly would nearly stop completely with each compression stroke. After a 2nd compression stroke i stopped cranking because i knew i would bend something if i hadnt already. ive never hydrolocked a motor before so i could very well be wrong, but aside from the facts pointing towards hydrolocking, it really felt and sounded like what i would expect a hydrolocking motor to feel and sound like, but ive still got alot to learn lol. after i got it home 2 days later and put an actual tb gasket on it acts differently when it stalls now because it will continue to crank and crank fine at normal speed/rythem.

a few months ago when i had to swap out the SD headers for the stock exhaust in order to comply with smog i put in all new gaskets and sealed, torqued, resealed, and retorqued the e manifolds, crossover, downpipe and had a ***** of a time ruling out all exhaust leaks. and now out of nowhere i have massive exhaust leaks from everywhere. i figured low back pressure, o2 sensors reading false o2, and injectors at max trim may be usefull info to the diagnostic.

i have an l67 and not an l34, does this issue on the naturally aspirated version carry over to the l67 at all? that would be nice cuz i have an extra blower and lim.

my bad l36* not l34.