92 LeSabre misses and stalls
Halodule
05-29-2006, 07:03 PM
I have a 1992 LeSabre with only 50K miles. It occasionally stalls, generally in hot weather and generally after running for 30 or more minutes. When it stalls, it will restart after sitting for 10-15 minutes. Some of the other posts in this forum mentioned crank sensors and ICMs, and one of those might solve my problem.
However, I drove about 150 miles at 65 mph yesterday with no problem until I pulled into a restaurant for lunch. The car wouldn't start immediately after I stopped, but started fine 20 minutes with the hood open, suggesting the engine might have overheated. The coolant level was fine, but this car has idiot lights rather a temperature gage, so I really don't know what the engine temp was.
After lunch, driving on local roads, the engine began to miss, so I turned on the heater and rolled down the windows. No problem for the next hundred miles unless I turned off the heater. It was 95 outside the car and 110 inside, so this is a not a good solution!
This problem sounds similar to several other posts, but the other posts don't seem to have a single solution. Thanks in advance for your help, Hal.
However, I drove about 150 miles at 65 mph yesterday with no problem until I pulled into a restaurant for lunch. The car wouldn't start immediately after I stopped, but started fine 20 minutes with the hood open, suggesting the engine might have overheated. The coolant level was fine, but this car has idiot lights rather a temperature gage, so I really don't know what the engine temp was.
After lunch, driving on local roads, the engine began to miss, so I turned on the heater and rolled down the windows. No problem for the next hundred miles unless I turned off the heater. It was 95 outside the car and 110 inside, so this is a not a good solution!
This problem sounds similar to several other posts, but the other posts don't seem to have a single solution. Thanks in advance for your help, Hal.
maxwedge
05-29-2006, 07:43 PM
When it won't start you must confirm spark at at least the 3 ft plugs and injector pulse, 1st step in the diagnostics, post back results.
HotZ28
05-29-2006, 08:56 PM
The problem should have set a crank sensor code, but it may not, however all indications point to your crank sensor failing due to heat soak.
:newburn:
You will not have spark to the plugs, until the sensor cools down!
You can test the crank sensor resistance while it is cool and it will probably be within the range of the spec. The spec on the crank sensor should read between 700 and 900 ohms. The problem most people run into when testing the sensor is they usually test it at ambient temperature, not when it is hot. Running the air conditioner will add to the under-hood temp, due to the fans pulling hotter air through the condenser.
When you have an intermittent problem such as yours, the best solution is to remove the crank sensor, place it in a pan of hot water and hook up your DVOM to watch the sensor's resistance as it warms up. (Check it all the way up to a boil). If it is a bad sensor, resistance will increase until it suddenly goes open. (That is the point where your car shuts down)!
Now, pour out the hot water and add cool water and conduct the test again. You can watch the resistance fall and go back into the normal operating range. This would explain the no start problem when the engine/sensor is hot. The crank sensor will absorb heat when the engine is running and even more when the engine is shut down. (No air movement)
That is the reason some fail to start after a short drive in hot weather after the engine is turned off and the person tries to start it again, after only a few minutes cooling time. Actually, the sensor is absorbing more heat while the engine is off. :angryfire
Now, there is another water test you can try that will tell you the same thing without removing the crank sensor. Keep a gallon of water in your car for the next time it stalls. (If you have a pump garden sprayer that would be even better)! When the car stalls and will not start, open the hood and pour (spray) water on the crank sensor to cool it down. If what we suspect here is true, when the sensor cools down, the car will start and run normally. (Until the next time it overheats)!:devil:
:newburn:
You will not have spark to the plugs, until the sensor cools down!
You can test the crank sensor resistance while it is cool and it will probably be within the range of the spec. The spec on the crank sensor should read between 700 and 900 ohms. The problem most people run into when testing the sensor is they usually test it at ambient temperature, not when it is hot. Running the air conditioner will add to the under-hood temp, due to the fans pulling hotter air through the condenser.
When you have an intermittent problem such as yours, the best solution is to remove the crank sensor, place it in a pan of hot water and hook up your DVOM to watch the sensor's resistance as it warms up. (Check it all the way up to a boil). If it is a bad sensor, resistance will increase until it suddenly goes open. (That is the point where your car shuts down)!
Now, pour out the hot water and add cool water and conduct the test again. You can watch the resistance fall and go back into the normal operating range. This would explain the no start problem when the engine/sensor is hot. The crank sensor will absorb heat when the engine is running and even more when the engine is shut down. (No air movement)
That is the reason some fail to start after a short drive in hot weather after the engine is turned off and the person tries to start it again, after only a few minutes cooling time. Actually, the sensor is absorbing more heat while the engine is off. :angryfire
Now, there is another water test you can try that will tell you the same thing without removing the crank sensor. Keep a gallon of water in your car for the next time it stalls. (If you have a pump garden sprayer that would be even better)! When the car stalls and will not start, open the hood and pour (spray) water on the crank sensor to cool it down. If what we suspect here is true, when the sensor cools down, the car will start and run normally. (Until the next time it overheats)!:devil:
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