98 Saturn sl2 shuts off while driving
#2
06-28-2018, 12:56 PM
The best possible answer comes from the best possible description of the problem,
It shuts off while driving:
1) before the car gets to operating temperature? After? Randomly with regards to engine temperature?
2) about the same operating temperature each time per the dash gauge?
3) Service Engine Soon light lit? if so, what are the codes?
4) Is it only under heavy load (going up a hill) or has it happened on flat road as well?
5) Does the car lose speed and power and sputter then stall or does it just stop firing and shut off?
6) cannot be restarted after it shuts down until it cools?
7) After the car stalls, do you still have spark at the spark plugs?
If the answer to 4 is doesn't matter, 5 is it just stops, 6 is almost always yes, and tracks with 7 being no, the most likely explanation is a defective Crankshaft Position Sensor (CKP).
The car uses information derived from this sensor and others to determine where the engine internals are in their rotation, Without a valid CKP signal, the PCM does not know where the engine is in its rotation.
In order to prevent engine damage, the PCM kills fuel and spark and the car simply stops running.
Heat cycling of the CKP from 1000's of trips eventually takes its toll on these sensors. The windings inside will usually go open circuit.
No CKP signal = No spark + No fuel = No go
To make checking for spark easier, buy an extra spark plug for the car (NGK Stock #5643 is for the BKR5ESA-11 for the DOHC plugs) and gap it to 0.040 in. When the car stalls, PULL the FUEL INJ fuse from the underhood junction boxx. This sounds counterintuitive but these cars easily run on three cylinders and if it happens to start up again, you do not want to be leaning over the engine when it does.
.
Pull a spark plug boot from one of the plugs in the engine, insert your extra plug into the boot, hold by the WIRE with the tip up against an unpainted metal surface and crank the engine.
If you see no spark, reposition the plug and try again. If you still see no spark, CKP is probably the issue. Test is much easier done by two people......
Many tend to flake out when they go bad and exhibit the symptoms you see, right before they fail completely.
BE SURE TO RECONNECT THE SPARK PLUG WIRE YOU REMOVED.
BE SURE TO REINSERT THE FUEL INJECTOR FUSE IN ITS PROPER LOCATION
If you DO see spark, and can then start the engine immediately, then the chances of CKP being the issue are much lower.
There are other ignition system things that can happen, but this is the most common.
It shuts off while driving:
1) before the car gets to operating temperature? After? Randomly with regards to engine temperature?
2) about the same operating temperature each time per the dash gauge?
3) Service Engine Soon light lit? if so, what are the codes?
4) Is it only under heavy load (going up a hill) or has it happened on flat road as well?
5) Does the car lose speed and power and sputter then stall or does it just stop firing and shut off?
6) cannot be restarted after it shuts down until it cools?
7) After the car stalls, do you still have spark at the spark plugs?
If the answer to 4 is doesn't matter, 5 is it just stops, 6 is almost always yes, and tracks with 7 being no, the most likely explanation is a defective Crankshaft Position Sensor (CKP).
The car uses information derived from this sensor and others to determine where the engine internals are in their rotation, Without a valid CKP signal, the PCM does not know where the engine is in its rotation.
In order to prevent engine damage, the PCM kills fuel and spark and the car simply stops running.
Heat cycling of the CKP from 1000's of trips eventually takes its toll on these sensors. The windings inside will usually go open circuit.
No CKP signal = No spark + No fuel = No go
To make checking for spark easier, buy an extra spark plug for the car (NGK Stock #5643 is for the BKR5ESA-11 for the DOHC plugs) and gap it to 0.040 in. When the car stalls, PULL the FUEL INJ fuse from the underhood junction boxx. This sounds counterintuitive but these cars easily run on three cylinders and if it happens to start up again, you do not want to be leaning over the engine when it does.
.
Pull a spark plug boot from one of the plugs in the engine, insert your extra plug into the boot, hold by the WIRE with the tip up against an unpainted metal surface and crank the engine.
If you see no spark, reposition the plug and try again. If you still see no spark, CKP is probably the issue. Test is much easier done by two people......
Many tend to flake out when they go bad and exhibit the symptoms you see, right before they fail completely.
BE SURE TO RECONNECT THE SPARK PLUG WIRE YOU REMOVED.
BE SURE TO REINSERT THE FUEL INJECTOR FUSE IN ITS PROPER LOCATION
If you DO see spark, and can then start the engine immediately, then the chances of CKP being the issue are much lower.
There are other ignition system things that can happen, but this is the most common.
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