Buick 3800 no start/cutout issues (long)

[PB86MCSS]

This weekend I took my daily driver LeSabre to the Wisconsin Dells. Little backstory which might or might not be related to the issue, I "upgraded" the ignition from the Magnavox style to the Delco II last weekend and also got new correct for the ignition 93' LeSabre plug wires, Bosch brand not that it matters. Module/Coil setup was from a junkyard car that was fresh, fired up right away and ran great. Drove it each day during the week to work and back, to my parents, softball, etc...probably put on 40 miles-ish, no problems. Drive up to the Dells, no problems. Drive around the Dells Friday night and all day Saturday, no issues there. About to leave last night as my gf needed to work in the AM today, get some Arby's and leave the drive through, car is idling fine then just cuts out. Cranks just fine and feels like it wants to start (hard to explain, not just a dry cranking feel/sound) but no dice. Let it sit awhile, crank some more, try flooring it to tell the ECM to not give it gas, nothing. I have two spare Maganox module/coil setups in my trunk, more on that later, but no tools. Luckilly a good friend of mine was at his familys place in the Dells from out of town, so I called him up, he was close by and picked me up, took me back to their land and grabbed the tools I'd need to swap the coil/module, which I felt was it. Swap it out, fires up, stumbles but runs...I believe it stumbled only because it was kind of flooded from all the cranking. Whew, runs...ok....get on the road, drive about 30 or so miles, close to Madison then while doing 65-70 the car starts to cut out and nothing from the engine....coast to an exit ramp. Car won't start, same symptoms as before. The SECOND coil/module I have in my trunk, another Magnavox style was removed from the car by a GM dealership right after I bought it in the winter of 2005...supposedly the resistance between the coils was bad so they replaced it. Not sure why I kept it other than the module was ok I thought perhaps, so it sat in my trunk for the last 4 years. Swap it out and the car starts up....stumbles again but I hold the RPM's up to 2000+ for a bit to get the gas cleared out. Start driving and make it all the way back home, car ran fine. Park the car late last night and for shits and giggles try to start it, same problem...no fire but a solid crank and the "feeling" it wants to start but something with the ignition is off. Ok...I'm at a loss. There is no way the car happens to get 3 bad coil/module setups. I don't think this is an alternator/battery issue as it cranks, the voltage was fine according to the stock gauge during the drive. Too late to go out and check the fuel pressure (I'll do that in a bit) but could it be a fuel issue causing flooding? Some wire or ground that I'm missing for the ignition? I guess I'm not sure how I made it home if there is a problem...the fact the only spare parts I have are two module/coil setups is bananas too.

Anyone have an idea? Today after checking the fuel pressure off/key on/cranking I will take the spare modules/coils to the store to get tested too.

[Holeshot]

Crank position sensor? Also the harmonic balance are known issues. The rubber between the pulley and the weight rots and will give erratic readings to the crank sensor.

[PB86MCSS]

Just went out, fuel pressure tests fine. Car started right up too...moved it to my driveway and parked it, started it up again just fine. Not sure what the deal is, I looked over and didn't see anything obvious for wiring as an issue. Could something cause this only when warm? Those are the only times it has cut out on me.

I wonder if the balancer or sensor would go in and out and be a problem when warm? Something odd that when I swapped modules/coils the car would start each time.

[BadAzzGTA89]

IGN module might be getting heat soak??Did you put the grease between were it mounts??

[PB86MCSS]

I failed to do that...which might explain the issues, I bought some heat sink grease today but it might be too little too late. Car runs fine when cold but still dies out when warmed up and needs to cool off to run again.

I plan to swap the crank sensor tomorrow, bought one today....and I might steal my parents 93' LeSabre coil/module setup tomorrow too, they are gone until Saturday anyway, I'll plan to hit up Al's or something for some spares.

[BadAzzGTA89]

I failed to do that...which might explain the issues, I bought some heat sink grease today but it might be too little too late. Car runs fine when cold but still dies out when warmed up and needs to cool off to run again.

I plan to swap the crank sensor tomorrow, bought one today....and I might steal my parents 93' LeSabre coil/module setup tomorrow too, they are gone until Saturday anyway, I'll plan to hit up Al's or something for some spares.

I would do that then instead of throwing parts at the car might be as easy as spreading some grease!!

[Reverend Cooper]

my thought is crank sensor also,when it gets hot resistance builds up,after sitting a bit it cools off and starts working again

[PB86MCSS]

Just swapped the crank sensor...car is running fine and re-starting when hot just fine, so far so good.

The scantool is reading open loop now though, hmm. Car has idled 20 minutes or so with temps up to 200, kind of odd.

[theavenger333]

OEM thermo in there is 195 so up to 200 isn't bad.....i run a 180 in mine

[PB86MCSS]

The temp wasn't odd, I meant that it wasn't in closed loop ...drove it and after being in drive it achieved closed loop, I guess I didn't think since it was in park it might not close .