92 3.4 DOHC dies after hot

[943100Base]

So my sisters 92 Lumina Euro 3.4 has a rather anyoning problem. After the car warms up and reaches normal operating temp, it shuts off. I have fuel, but no spark. pulled a couple plugs to find that out. I just put in an ignition module and replaced the coils and it still does it. I know the car has a couple sensors that are linked to killing the motor if one goes bad or detects something wrong, like crank and temp. I dont think that 92's had the cam sensor, so thats out. i know the crank sensor is linked to spark, but if thats is, where is it and how i get to it? And is it hard. i need to get this fixed cause i dont want her to sell the car and have it got to someone that wont appreciate a rare car.

I need help!

[HayesPerformance]

Was it a new ignition module?

[HayesPerformance]

and is it No Spark on all the wires?

[943100Base]

well newer ignition module. it came from a perfectly good running car that drove great. and yeah, no spark on all 6 wires/plugs. funny thing is, after i put this other ignition mod in, the car started up better than it ever has before. so would crank sensor be the problem?

my chiltons doesnt say where the crank sensor is either. it just says remove it, inspect the o-ring then reinstall new sensor. WTF is with that? they usually tell you where it is.

[HayesPerformance]

hahahahahahaha.

You'll have some REAL fun getting to the Crank sensor. Its the most terrible job! Its in the block on the BACK SIDE, in the middle just a couple inches up from the oil pan.

Is yours a automatic?

[943100Base]

yes, yes it is. and thats what i was fearing is where it was. can i pull the exhaust to help with room to get in there?

[943100Base]

and my question still remains, would this sensor kill the spark after it warmed up? is there any other sensor that would do this?

[MONICAZ34]

You say that the car starts up then reaches normal operating temperature, so there has to be some kind of spark. I think. But then it just shuts down. I have actually seen this before, the guy said he replaced the coolant temperature sensor and the thing worked normally after that.

[Carlspike]

This happened to my Z34. It was the crank sensor. A good way to tell for sure is to drive the car with the scan tool on it and when it stalls verify that there is no crank reference. The sensor is a metal core surrounded by plastic. The plastic will crack but when the engine is cold the crack won't be big enough enough to throw off the sensor reading. Once the car drives 15-20 minutes the plastic will expand enough for the sensor to not work properly. With an automatic trans it is a pretty big pain. Pulling the exhaust at the down pipe gives you more room, take it all the way out if you can. You also have to move aside the cooling duct for the alternator. After that you can unplug the sensor and take the bolt out, then the really fun stuff comes. You have to wiggle the sensor out bit by bit. It took me and another guy about 3 hours of wiggling to get the sensor out without breaking it. If you have access to them then the tool used for pulling off small coolant hoses works pretty good. Do your very best not to break it in half because if you do then you're really in trouble. If you do happen to break it I've been told that you can get a coat hanger hot with a torch and stick it into the plastic, melting it in there. After it dries then you can try to pull it out. Good luck.

[dohcfiend]

i feel for you bro, crank sensor is pretty easy if you have a manual but for the auto's it is a pain.

it is on the backside of your block a little above you oilpan sitting between the engine and tranny(kind of close to that alt vent if memory serves) with a 2-wire connector plugged into it that coincedently(not really) goes to your ign module.

and yes it sounds like your problem and this is why: from years of heatsoak and cooling the plastic housing has cracked somewhere. when the engine gets hot it expands and the crack gets larger possibly allowing something in or just distorting the signal. when your engine is cold the housing is contracted and sealed.

but not only is it a PITA for an auto but there is a 50/50 chance it has gotten larger than it's original design and if this happens it will most likely break in half during removal and you'll need something to push it through(or try the coat hanger trick) and subsequantly have to remove your oilpan to get the remains and plastic shards out.

good luck.