1995 Sw2 wagon…engine will abruptly studder and just stop running. I pull over and turn the key off and then restart and it does start. Never know when it is going to happen. Was seeming that the negative battery cable kept coming loose because there were times when it wouldn’t even start but when I tightened the cable nut I got power. Now that doesn’t seem to be the case. It seems it is an electrical problem to me but I’m not sure at all. Would greatly appreciate any feedback. Dovetail
Sudden engine shut off
- Thread starter dovetail
- Start date
Derf
Moderator
First thing to check is for corrosion on either the positive or negative battery terminals as well as the battery cable connections, positive and negative.
Next, check the end of the negative battery cable where It bolts to the frame of the car. If this connection gets corroded or loose, you can have intermittent grounding problems. If corroded, let it soak in some PB blaster penetrant. Do not use WD-40 has it is a water repellent not a penetrant, unless you buy the WD-40 that says it is a penetrant on the can. Then use your socket set to loosen the bolt. Sand the rest off the spot where the cable end meets the frame. You want bare metal. Sand the end of the negative battery cable so that you have bare metal. You'll likely have to replace the nut. Take it with you to a hardware store and find the right replacement.
Is the service engine soon or wrench light on on the dash?
Next, see if the battery cables are stiff and crunchy near the place where they attach to the cable clamps. They may be partially compromised by leaking acid from the battery.
General note: the negative cable must be cleanly attached to the body in order to complete the electrical circuit. If it's not, the battery will not get charged by the alternator. But that would only affect the ability to start, because the electricity provided to the vehicle is from the alternator once the car is started.
Above are the simple things to check.
There is a sensor called the crankshaft position sensor. It keeps track of information that sends a signal to the computer telling it where the crankshaft is in its 360° rotation. The computer has to know this so that it can time the spark for each cylinder to occur on the compression stroke. If that sensor starts to go bad, the computer will turn off the fuel injectors and inhibit the spark
If you are driving, if the computer can't get a legitimate signal for that sensor, it will kill fuel and spark and the engine will stall. This particular sensor can intermittently work as it starts to fail. It usually starts to fail when the engine is very hot and you turn the vehicle off. Once you turn the vehicle off the sensor absorbs even more heat. If you wait half an hour, it cools off enough to work properly.
But try the simple stuff above and have your charging system load tested at AutoZone or similar and report back
Next, check the end of the negative battery cable where It bolts to the frame of the car. If this connection gets corroded or loose, you can have intermittent grounding problems. If corroded, let it soak in some PB blaster penetrant. Do not use WD-40 has it is a water repellent not a penetrant, unless you buy the WD-40 that says it is a penetrant on the can. Then use your socket set to loosen the bolt. Sand the rest off the spot where the cable end meets the frame. You want bare metal. Sand the end of the negative battery cable so that you have bare metal. You'll likely have to replace the nut. Take it with you to a hardware store and find the right replacement.
Is the service engine soon or wrench light on on the dash?
Next, see if the battery cables are stiff and crunchy near the place where they attach to the cable clamps. They may be partially compromised by leaking acid from the battery.
General note: the negative cable must be cleanly attached to the body in order to complete the electrical circuit. If it's not, the battery will not get charged by the alternator. But that would only affect the ability to start, because the electricity provided to the vehicle is from the alternator once the car is started.
Above are the simple things to check.
There is a sensor called the crankshaft position sensor. It keeps track of information that sends a signal to the computer telling it where the crankshaft is in its 360° rotation. The computer has to know this so that it can time the spark for each cylinder to occur on the compression stroke. If that sensor starts to go bad, the computer will turn off the fuel injectors and inhibit the spark
If you are driving, if the computer can't get a legitimate signal for that sensor, it will kill fuel and spark and the engine will stall. This particular sensor can intermittently work as it starts to fail. It usually starts to fail when the engine is very hot and you turn the vehicle off. Once you turn the vehicle off the sensor absorbs even more heat. If you wait half an hour, it cools off enough to work properly.
But try the simple stuff above and have your charging system load tested at AutoZone or similar and report back
Derf
Moderator
How many miles are on the vehicle? Automatic or manual trans?
Is the service engine soon light on? If so, what are the stored codes?
-------------
When the car suddenly stops running, do the idiot indicator lights on the dash stay lit up with the key in the on position, or does the vehicle go entirely electrically dead? And is there a difference in Behavior for what I just described when the vehicle will restart immediately versus when it won't?
Do the radio presets remain as you set them, or do they go back to the defaults, along with the clock resetting?
Do you regularly use a modern high current phone charger in the cigarette lighter port?
What is the one constant thing that you do that allows the vehicle to be restarted in the cases where it will not immediately restart?
The next time this happens, and the vehicle cannot be immediately restarted,
Also, when the vehicle won't restart, does the engine crank but not fire or does it not crank at all? Or does it crank, fire, but just not start?
Right before the engine cuts out, do you notice strange drivability problems? Like the gas pedal becoming unresponsive?
(End of tests after vehicle stalls and will not restart)
------------
Please perform the following activities, one at a time and post the results here. If you do more than one at a time and your problem is solved, you will never know which activity fixed the issue.
Measuring the ckp resistance
Here is a link to the page for the ckp, but if you look at the top of the page, it is nested in the hierarchy of the entire electronic manual, so you can navigate to wherever you want to find whatever you want .
https://lemon-manuals.la/Saturn/199...rankshaft Position Sensor/Service and Repair/
Location of ckp:
https://lemon-manuals.la/Saturn/199... System/Crankshaft Position Sensor/Locations/
Remove the sensor and measure the resistance across the two terminals of the sensor. Ensure the probes from the multimeter do not touch or you will read zero erroneously. Reinstall the sensor and reattach the connector harness wiring.
Post results here.
----------
Cleaning the throttle body and idle air control valve IAC
Clean the throttle body with the throttle body still attached to the car. Remove all Air ducting attached to the throttle body. Use throttle body cleaner, paying special attention to the back of the throttle plate and to the channel at the bottom of the throttle body bore. Some of the cleaner will run back out of the throttle body, so have a shop towel situated below the opening to catch it. For stubborn deposits, spray the throttle body cleaner and let it sit for a few minutes. You can use a wire brush on the metal parts. The engine may be difficult to start after using the cleaner, but it will sort itself out.
Is there a hitch in the movement of the throttle body plate or gas pedal?
It's 5:15 in the morning and I need to go to bed. See if any of the above helps. Please post requested information. Thanks
Is the service engine soon light on? If so, what are the stored codes?
-------------
When the car suddenly stops running, do the idiot indicator lights on the dash stay lit up with the key in the on position, or does the vehicle go entirely electrically dead? And is there a difference in Behavior for what I just described when the vehicle will restart immediately versus when it won't?
Do the radio presets remain as you set them, or do they go back to the defaults, along with the clock resetting?
Do you regularly use a modern high current phone charger in the cigarette lighter port?
What is the one constant thing that you do that allows the vehicle to be restarted in the cases where it will not immediately restart?
The next time this happens, and the vehicle cannot be immediately restarted,
- leave the key in the on position
- open the driver's door.
- Does the dome light turn on?
- Do you hear the chime noise since the key is still in the ignition in the on position?
- Does the cigarette lighter function?
Also, when the vehicle won't restart, does the engine crank but not fire or does it not crank at all? Or does it crank, fire, but just not start?
Right before the engine cuts out, do you notice strange drivability problems? Like the gas pedal becoming unresponsive?
(End of tests after vehicle stalls and will not restart)
------------
Please perform the following activities, one at a time and post the results here. If you do more than one at a time and your problem is solved, you will never know which activity fixed the issue.
Measuring the ckp resistance
Here is a link to the page for the ckp, but if you look at the top of the page, it is nested in the hierarchy of the entire electronic manual, so you can navigate to wherever you want to find whatever you want .
https://lemon-manuals.la/Saturn/199...rankshaft Position Sensor/Service and Repair/
Location of ckp:
https://lemon-manuals.la/Saturn/199... System/Crankshaft Position Sensor/Locations/
Remove the sensor and measure the resistance across the two terminals of the sensor. Ensure the probes from the multimeter do not touch or you will read zero erroneously. Reinstall the sensor and reattach the connector harness wiring.
Post results here.
----------
Cleaning the throttle body and idle air control valve IAC
Clean the throttle body with the throttle body still attached to the car. Remove all Air ducting attached to the throttle body. Use throttle body cleaner, paying special attention to the back of the throttle plate and to the channel at the bottom of the throttle body bore. Some of the cleaner will run back out of the throttle body, so have a shop towel situated below the opening to catch it. For stubborn deposits, spray the throttle body cleaner and let it sit for a few minutes. You can use a wire brush on the metal parts. The engine may be difficult to start after using the cleaner, but it will sort itself out.
Is there a hitch in the movement of the throttle body plate or gas pedal?
It's 5:15 in the morning and I need to go to bed. See if any of the above helps. Please post requested information. Thanks
Thank you. For sure, the car always restarts after these episodes. I’ve replaced the crankcase position sensor and have performed all your other suggestions. Looking now into a possible ERG valve failure
Mileage 142,000 manual trans . Performed pretty much all your suggested tests. Note that the car always restarts after after an episode. Replaced the crankcase position sensor valve. Though I have recently cleaned the throttle body and a year or more ago replaced the idle valve, I’ll look back into that. Currently looking at the ERG valve. Drove around the block and as I slowed to a stop the RPMs dropped to just short engine killing with clutch in or at idle. Rev the engine and the idle goes to normal, approx. 800. Same results when I’d drive 30 feet and slow, did it 3 times. Same. I’m by no means a mechanic, but I do try my best to attempt to fix things if I can. I feel determined. Thank you for your involvement.
Derf
Moderator
EGR failure or impeded pintle movement from build up carbon usually caused by oil burning. But you have an SOHC so oil burning should not be an issue....
EGR faults are thrown pretty easily on the OBD1 Saturns. Not saying it can't be the case..... And I have had EGR issues that did not code, when I took my foot off the gas during deceleration, the RPMs would dip and surge and dip and surge all over the place, finally dropping to below idle installing. The car wouldn't restart for 3 minutes afterward due to some strange pressure equalization thing. Then it would start it as though it never happened.
EGR faults are thrown pretty easily on the OBD1 Saturns. Not saying it can't be the case..... And I have had EGR issues that did not code, when I took my foot off the gas during deceleration, the RPMs would dip and surge and dip and surge all over the place, finally dropping to below idle installing. The car wouldn't restart for 3 minutes afterward due to some strange pressure equalization thing. Then it would start it as though it never happened.
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