Mechanics

DIE NO RESTART

1992 Saturn SL2 • 4 cylinder FWD Manual • 180,000 miles

I have a 1992 Saturn SL2 DOHC. It will start and idle fine for 5-10 minutes and then will die. Will not restart. After waiting for a while (30 - 60 min) it will start again and do the same thing. I can turn it off immediately after starting and it restarts. No check engine codes
Thanks for your help.
casey591
Avatar
Casey591
January 10, 2011.



First thing we need to do is when it dies and won't start is see if we have spark then if we do then we need to see what the fuel pressure reading is. Let me know what you find.

Saturntech9
Jan 10, 2011.
Has spark. Can hear the fuel pump come on and stop when turning switch to on position. It just restarted. I am letting it idle to see if it stops again. I did wiggle the two connectors to the two temp sensors in the right side of block before starting. Could a bad connection cause my problem?
Thanks,
casey591

Tiny
Casey591
Jan 10, 2011.
Those car's are known for bad coolant temp sensor's it would be the bottom sensor with two wire's going to it. The sensor's are only 10 also inspect the connector if it's corroded the sensor would have to be replaced. Hearing the fuel pump kick on doesn't mean you have enough fuel pressure to start and run.I have seen plenty of fuel pump's go bad and you can hear them run but didn't have the proper fuel pressure. So when it didn't start you checked for spark?A bad coolant temp sensor and or corroded connector could cause your problem though. It's only 10 a cheap try and it's pretty common for them to go bad.

Saturntech9
Jan 10, 2011.
Thanks, I will try the coolant sensor however my bottom sensor has only one wire, it is the top one that has two wires. Is there something wrong with that? Also you are regarding the spark when not starting, I have not documented that. I assumed I have spark since the engine eventually starts again. I will check for spark now that it will not start at all. The final time that it started I was able to drive for 4 blocks until it died. Prior to that it had died after idling for 15 min and driving about 1 mile. When it died the last time it was like I had turned off the key, then turned it back on and finally turned it off. Seemed to be ignition in nature rather that fuel starved. Please confirm the "two wire" sensor on bottom rather than the "one wire" that I have on bottom. Are the sensors identical?
'casey591'

Tiny
Casey591
Jan 11, 2011.
The sensor's are not the same the top one is for the gauge it usually has a white looking end where the connector goes. The top one has a single green wire going to it for sure. The bottom sensor usually has a brown end where the connector goes on. The bottom one has two wires going to it a yellow one and a black one for sure. When it die's and won't start you need to see if it has spark you could be loosing spark when it dies and won't start. Let me know what you find with the sensor's that could be a problem also. Make sure the coolant sensor connector's aren't corroded if the are they will have to be replaced.

Saturntech9
Jan 11, 2011.
Sensors seem to be fine by resistance testing, correct wiring(just a lapse in my memory) no corrosion on connectors. Starts after sitting for a long while. Runs for about 5-10 minutes the begins to falter and dies. No restart. Application of starting fluid to Air intake and it acts as though it wants to start but does not. Cannot document spark by conventional means (disconnect from coil pack and look for spark through air gap from coil contact to end of wire inserted into coil wire boot). Battery has run down so removed to recharge (this will reset PCM). So I will let you know after reconnection and attempt to restart with "clean" program.
I appreciate your help.
Casey591

Tiny
Casey591
Jan 12, 2011.
The best way to check for spark is to remove two spark plug wire's from the coil tower's that are side by side and crank it and watch for a spark to jump from tower to tower. How did you test the coolant temp sensor's with a resistance check?Did you use the resistance chart and compare the ohm's value to the correct coolant temp?Or did you just see if they had resistance?Because there variable resistor's depending on what temp there exposed to the resistance value change's. The only one that would keep it from starting is the bottom one.

Saturntech9
Jan 12, 2011.
Charged battery. Replaced Temperature Sensor. Engine Started, ran for 15 seconds partial throttle, then died when throttle down. No restart. Cannot see spark between to terminals on cranking.
Thanks,
casey591

Tiny
Casey591
Jan 14, 2011.
Update from previous reply. I tried again to see a spark between terminals of either coil pack. Also checked coil resistance. Coil pack 4-1 had fluctuating 5k-7k ohms resistance between terminals. Pack 2-3 had steady 7.8k ohms resistance. Tested for spark on 4-1 pack - no spark.(2-3 wires attached to their terminals) Tested 2-3 for spark (4-1 wires attached to their terminals) Initial spark and ignition in engine then die / no spark). Both packs now register steady 8k ohms resistance but no spark. Seems to definitely be ignition problem.
Any thoughts?
Casey591

Tiny
Casey591
Jan 14, 2011.
Third addition. I took off the coil packs with control unit and checked for shorts to ground (base plate of control unit) and resistance in coils off of the control unit. 8k ohms both packs. Infinite resistance between coil towers and base plate (ground). All contacts clean. After re-installation the engine started right up partial throttle idle (2200rpm) for 10-20 seconds slight falter when easing on throttle so throttle back to 2200 for 20 more seconds throttled back to 1500 for 10 sec then falter and die. No restart no spark.
Your help is appreciated.
Casey591

Tiny
Casey591
Jan 14, 2011.
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