1993 Buick Century 93 Buick Century engine shots off in hot

What happened to O2 ? you say blown mean out of exhaust or just failed and set a code?

Hello, I'd start with the basic tests. Your obd1 so you should be able to check codes yourself.

When it refuses to start, have a helper crank it, while you check for spark at the plugs and injector pulse.

You might also check the coolant temp sensor.

[quote:d10536b66c="Docfixit"]What happened to O2 ? you say blown mean out of exhaust or just failed and set a code?[/quote:d10536b66c]

When we got home and had our mechanic check the car to find out why it stopped, he ran a diagnostic and got a code that indicated the O2 sensor was bad. We then replaced the bad sensor.

[quote:1f64cf6ae8="jdl123"]Hello, I'd start with the basic tests. Your obd1 so you should be able to check codes yourself.

When it refuses to start, have a helper crank it, while you check for spark at the plugs and injector pulse.

You might also check the coolant temp sensor.[/quote:1f64cf6ae8]


What is OBD1? It does not crank. It shuts off suddenly while we are on the hiway going hiway speed. We coast to the side of the hiway. The car will not crank or do anything for at least 20 minutes. Eventually it will crank and start. It runs perfectly for a while, then shut itself off a little further down the road, less than 1 hour later. Until the ambient air temperature gets low enough that it decides it will run without stopping.

The coolant is not hot. The engine does not overheat. The temperature is in the safe range the whole time, according to the gauge on our dashboard.

O.K. so starter does not crank engine ? do you have dash warning lights? does all electrical function stop?

[quote:dc11812934="Docfixit"]O.K. so starter does not crank engine ? do you have dash warning lights? does all electrical function stop?[/quote:dc11812934]

Good question...this was years ago and I'm only asking because someone wants to drive it to LA. We have another car we take on road trips now, this car has been used for local driving only in recent years. Forgive me if my memory is fuzzy.

My recollection is that the electrical works, but the car will not crank. It's as if something decided it was too hot for the car to run, so IT prevented the car from turning over until IT decided it was cool enough. I don't think this car has dash warning lights. If it does they never went off from this.

Of course we don't run anything in the car until after it will start again, don't want to run down the battery. We also don't run the A/C when we're driving in such hot weather. While we're sitting there not moving my husband got out and looked at the engine. It did not show any signs of overheating (such as steam or fluid spurting from the radiator). We maintain the car well, and check everything and change oil and fluids before going on such a long trip, so anything that would be prevented by normal maintenance would not be the cause.

I'm not sure of the exact temperature outside, this car doesn't have a thermometer for that like the new ones do. However, out new car would show 100 to 120 F in this type of weather. The air and road are so hot that if it rains the drops evaporate as they hit the road, or perhaps before. Maybe the hot asphalt is a factor in the car shutting off? Nobody else was stuck on the side of the road, other cars were going on their way.

The most common heat related fault to occure on this vehicle is faulty crankshaft sensor located behind crankshaft dampner./ Where it gets quite hot they later repositioned this part. Have you ever had car checked for trouble codes stored in computer?

[quote:42d7f2fc99="Docfixit"]The most common heat related fault to occure on this vehicle is faulty crankshaft sensor located behind crankshaft dampner./ Where it gets quite hot they later repositioned this part. Have you ever had car checked for trouble codes stored in computer?[/quote:42d7f2fc99]

Yes we had it checked, what code would that be? Would that be the same code as for the O2 sensor, or a different one?

Would that sensor tripping cause the O2 sensor to go bad? Or is there some connection?

If this is something that would be tripped by running on a really hot day on a hot road without the engine overheating, perhaps that is it.

My mechanic's take on this, beyond replacing the O2 sensor, was that it was probably another sensor, but it was expensive and wasn't worth the trouble to fix if we weren't going to drive it in that situation anymore.

Thanks for sharing your ideas on this!

Crank sensor will not set code about $45 part. The other thing that maybe suspect is Ignition control modulr thats $325.

[quote:bd9f4ca1da="Docfixit"]Crank sensor will not set code about $45 part. The other thing that maybe suspect is Ignition control modulr thats $325.[/quote:bd9f4ca1da]

Would the crank sensor shut down the car if it got too hot?

Would the ignition control shut down the car if it got too hot?

The crank sensor sounds like a good suspect, especially if it caused this problem and got relocated because of it.

If one of these is the problem, would there be any other symptoms? This car has no problems driving around town. Starts right up, drives great. Only issue is if you're cruising at above 40 mph with your foot on the accelerator, it sometimes gets a mild vibration. This goes away if you take your foot off the accelerator for a moment, doesn't come back when you put your foot back down. This showed up after we rebuilt the trans, so I figured it was related to that. But maybe it could be related to this problem of the engine dying?

$45 sounds very reasonable. ;-)

No if crank sensor it would just die like you turned key off. And will restart and run like nothing happened.

[quote:a9051fb8da="Docfixit"]No if crank sensor it would just die like you turned key off. And will restart and run like nothing happened.[/quote:a9051fb8da]

Hmmm... It shuts off only when driving on the freeway at speed for 4 hours or more in extreme heat (probably 110 to 120F). And it won't start until it feels like it has cooled down, at least 20 or 30 minutes, but when it does start it runs perfectly. BUT: If the temperature out is still high, it will shut itself off again after about 1/2 hour of driving. It will keep doing this (shutting itself off and going only a short distance when it does start) until the temperature out drops below 100F, after which it goes back to running perfectly, without unplanned stops, for the rest of the drive.

The strategy has been to deal with this by getting to the nearest air conditioned building and hanging tight until the outside temp drops below 100. Unfortunately this usually happens no-where near anyplace with any building, like the middle of the Mojave Desert for instance.

The current strategy is we don't drive this car cross-country in hot weather anymore...but it would be nice to have that option, if we could figure out why it's doing this and get it fixed.

After it does this (it has only happened twice in over 10 years) our mechanic has found that the O2 sensor is no longer good, but has not found anything else obviously wrong with the car.

[quote:42499bbcae="Docfixit"]No if crank sensor it would just die like you turned key off. And will restart and run like nothing happened.[/quote:42499bbcae]

I checked what could cause an O2 sensor to go bad, and one answer that seemed promising was a faulty ground circuit on the wiring harness. This would cause reduced voltage and excessive heat. That excessive heat, combined with excessive heat outside, might cause the computer to crash, which would of course shut down the engine electronic systems until it was cool enough to reboot.

What do you think?

As my brother, the computer technician, says: If you want to really mess something up, get a computer involved. (Stated before they started putting computer chips in cars)

I think I'll have my husband check that ground wire, or the voltage, or something. He's an electrical technician and has those meter thingeys that you hook up to measure current.