Car randomly shuts off while driving

Tim Groth

Tim Groth

SCCoA Member
So this started on the trip to Carlisle. Essentially we made it 20 miles up the road...car turned off while driving, coasted to the shoulder of the road. I cranked it a few times maybe 2 mins at the most...fired back up...drove to Carlisle (300 miles) ran fine all weekend, drove back home 300 miles. No hard starts, no missing, no signs of anything more than a hiccup. Car runs exceptionally smooth when its running.

Last week the car turned off on the way to work. This time I had to try for about 10-15 mins. Finally fired up, made it to work. Come out after work, runs fine...been running fine all last week. Today Died again on the way to work...this time at a stop light. about 10mins of impeding traffic it again fires and runs...this time I make it about 1/2 a mile it turns off. It will crank for days but fires at will...once running again it's usually smooth and fine.

Car's a 1989 5sp just rolled 227k (not sure of the repair history) stock minus exhaust and Gen 2 M90.

When the car broke down I checked the common items - Crank Bolt (it's still there) Fuel Pump Primes (have the easy access hole under the seat) jiggled the wiring harness for the DIS/Cam/Crank...nothing.

Today for my peace of mind I bought a new DIS and Crank Sensor...I am confident it's sensor related giving its all or nothing. Any other suggestions or things to try would be great. I plan to replace the fuel filter after work, waiting now on the wife to drive me to the car, so it may run fine, may do nothing.

Thanks for any suggestions...

-Tim
 
My '90 did that when I first got it - eventually came done to cam sensor and front harness.

I had other symptoms, tho - hard start until 3rd try when the EEC steps in, finally, and tach drop.

I think the shut downs are when the EEC scans the sensors to see if signals are back, and spark is lost in the process.
 
Thinking back Cam Sensor was replaced this time last year but had a very different problem...I'd link the thread but now on my cellphone. When the Cam Sensor went I just left it unplugged and did the 3 cranks trick till it fired, again this is no symptoms then doesn't run at all...first thoughts for me are always balancer, which I'm find replacing as 300 in parts is still less than a car payment. Expense is of little concern at this point it's simply point me in the right direction.

-Tim
 
Tim Groth said:
Thinking back Cam Sensor was replaced this time last year but had a very different problem...
Click to expand...

BTW, I just got 18 months out of my last new cam sensor. Replaced it a month ago.

I'm starting to wonder if a worn cam sensor stalk/drive isn't the real culprit.
 
So car drove fine after work...made it 10 miles before dying...got it restarted and made it the last 2 miles home. For my humor I pressed the Schrader Valve while running... about a 1 inch fountain came out...so I'm leaning first towards full. Picked up a filter and going to install now. Hopefully it's that simple, but only tomorrow's drive will tell.

-Tim
 
Might be interesting to see what if any codes are being thrown. My money is on SPOUT.
 
A clogged fuel filter won't cause it to just shut off without any drivability issues. It almost sounds to me like it might be a bad ignition switch losing contact. Next time it happens, start by seeing if you hear the fuel pump prime when you turn the key on. If you do, then that means the ECM is getting power, and at that point start looking for something spark related. If you don't, then check if you have spark and injector pulsation when cranking. If you have no fuel pump, no spark, and no injector pulsation, then likely your ECM is losing power.
 
MadMikeyL said:
A clogged fuel filter won't cause it to just shut off without any drivability issues. It almost sounds to me like it might be a bad ignition switch losing contact. Next time it happens, start by seeing if you hear the fuel pump prime when you turn the key on. If you do, then that means the ECM is getting power, and at that point start looking for something spark related. If you don't, then check if you have spark and injector pulsation when cranking. If you have no fuel pump, no spark, and no injector pulsation, then likely your ECM is losing power.
Click to expand...

So fuel filter wasn't clogged or really that dirty for that matter...I came to the same thought process as you've outlined after I checked fuel, that it doesn't fall in line with the all or nothing problem. Suppose it was more piece of mind for me given I like to cross out any inexpensive/easy repairs first.

I know when I turn the key forward the fuel pump primes - again with the hole under the backseat helps with checking that..also was one of the first things I checked. With the key in the "run position" I can hear a buzzing sound at the backside of the supercharger - assuming this is a relay that sends power to the injectors. If I unplug the DIS the sound goes away. I have a new DIS module coming today. I've never had a DIS fail - always understood the failure to be heat related which doesn't make since when I drove 2 and from Carlisle w/o issue.

Guess I will install the new DIS tonight and have the old one tested - Even installed I don't know if it will give a clear yes or no immediately on if the problem is corrected given its randomness.

-Tim
 
Well project is on a stand still - every part I've needed has not been a stock item - causing me to be delayed by shipping.

Fuel filter has been replaced - again no change there besides it needing to be replaced.

For my peace of mind, I went ahead and purchased a Powerbond Balancer, Crank Sensor, DIS Module, and a new front cover gasket. Not knowing the age or history of these parts and the 227k miles on the engine it is just part of the territory in my eyes. Car is also leaking oil all over the front of the engine, so figure I may as well be proactive and not have to worry every time I drive, because of cutting corners. Plan to start tearing it apart tonight, as the parts should all arrive by Friday.

Keep this thread posted as I go.

-Tim
 
Hey Tim.... didn't I give you a packet of the service history of the car? If not I might still have it I will take a look. Chris V might remember what I had him replace on the car as well.

Chris C.
 
Boostin89SC said:
Hey Tim.... didn't I give you a packet of the service history of the car? If not I might still have it I will take a look. Chris V might remember what I had him replace on the car as well.

Chris C.
Click to expand...

Nothing I've seen - I have a list of the stuff I have replaced but otherwise I do not know.

At this point I have replaced almost every part under the hood, since I did the HG repair and also made sure the necessary parts were replaced at the time that was done.

If you find the folder it would be great to have tho!

-Tim
 
when i was having the symptoms you describe happen with my car I swapped out the DIS and it has run fine ever since.
 
SCarSC said:
when i was having the symptoms you describe happen with my car I swapped out the DIS and it has run fine ever since.
Click to expand...

DIS was the culprit of my issues - I replaced that and it fixed my random turning off stuff.

Given I had purchased the other parts, over the weekend I replaced the front cover gasket (was leaking horribly) balancer (had been replaced before with 4 cross threaded bolts :confused:) crank sensor appeared OEM - had 3 areas where it had rubbed on the belts and frayed the wiring (possibly part of the problem). Hope to have it all tightened down tonight and fresh fluids. Then comes some serious degreasing, hopefully this will put an end to any future surprises.

-Tim
 
Fuel

Just because the FP primes does not mean it is working properly. My Ford truck was doing the same thing, right up until it stopped working. I checked the FP pressure to the rail and guess what? it was working, but well below the 50PSI required to run the vehicle. Might check FP at the rail and go from there.
 
You must log in or register to reply here.
Back
Top