Engine quits while driving.

Skyjay · Post by **Skyjay** » Sun Feb 12, 2012 11:27 pm

Hey folks,
ran into this problem and it's a bit of a head scratcher I don't want to start throwing money at unless I know it's going to a good cause.
I have a 2002 Dodge SXT, MTX with 106k miles on it, good condition blah-de-blah.
So the other night I am driving home from a friends house when all of a sudden the engine cuts out on me. I was holding roughly 40mph on a level road and RPMs went to zero, but about half a second later it'll re-fire and off I went. About 2 minutes later the same symptom happened only this time it would not fire. Battery/lights were otherwise unaffected. So I pull over, attempt to start and the engine will not catch. Starter sounded fine, fuel pump primed, everything worked but the engine just wouldn't go. No check engine light, no codes, just won't go. Sit for about 15 minutes give or take, and tried again and the car fired up and I drove home.
Fearing some nasty issue I try the next morning with a CarChip and cruise around town and do some intense mountain driving to see if anything would come up. The data revealed nothing and at no point did the engine even hiccup. Later I drove to LA and back from SD, roughly 200-220miles at highway speeds. Still no issue.
This evening I drove home from work, and the engine did the same thing, flat road, around 40mph the engine dies, then kicks back to life. 2 minutes later the engine dies again and does no re-fire and I had to pull over and wait a time before I could fire it off again and drive home.
Again, no warning, no stuttering, no codes.
I broke down outside an autozone and they did a quick test of my electrical system for me (while I waited for the car to cool down or whatever) and revealed no generator issues, battery was fine, starting system working A.OK.

So I'm stumped guys, you have any ideas?
Cam/Crankshaft sensors were replaced under a year ago, and they would throw codes if there was an issue. Am thinking ECU, but would there be any other symptoms?
'Preciate the help guys!

boostalot717 · Post by **boostalot717** » Mon Feb 13, 2012 3:50 pm

fuel pump maybe???

What all mods are done to your car???

Post by **occasional demons** » Mon Feb 13, 2012 7:37 pm

ASD relay may be going bad. IDK if a fuel pressure issue alone would kill the engine and refire that cleanly.

I know my ASD relay killed my engine without any codes. The contacts simply quit conducting electricity. I swapped the horn relay in, and was on my way.

If the contacts are bad, there is no code for that, only the relay coil. The ASD will kill everything, injectors and coil, all at once.

It could also be as simple as a ground issue. Check the ground at the headlight on the tie bar, and the PCM to body fasteners for tightness.

edit:
A bad ign. switch could also cause those symptoms.

boostalot717 · Post by **boostalot717** » Mon Feb 13, 2012 9:09 pm

^^^^ Good info there. Never heard of a ASD going bad, but I guess it happens.

Skyjay · Post by **Skyjay** » Wed Feb 15, 2012 11:05 pm

Whelp I brought it to my mechanic and he had a fancy snap-on computer. Turns out there was a reserve code for a failed Crankshaft position sensor, swap them out and car runs as good as new.
I have to say I was never so relieved to see an error code pop up.

Thanks for the suggestions guys!

Post by **occasional demons** » Wed Feb 15, 2012 11:16 pm

Glad you got it fixed! Crank sensors will not always give a code when failing.

I figure swapping relays is free, if that doesn't do it, then move on to the stuff that cost $.

Alex Kurdian · Post by **Alex Kurdian** » Thu Feb 16, 2012 5:40 pm

Skyjay wrote:Whelp I brought it to my mechanic and he had a fancy snap-on computer. Turns out there was a reserve code for a failed Crankshaft position sensor, swap them out and car runs as good as new.
I have to say I was never so relieved to see an error code pop up.

Thanks for the suggestions guys!

Is the crank shaft sensor different to the cam sensor?

Post by **occasional demons** » Thu Feb 16, 2012 7:21 pm

Alex Kurdian wrote:
Is the crank shaft sensor different than the cam sensor?

Yes. The cam sensor reads the cam position, and after start up, controls the injector timing sequence. (So the injector only pulses when the corresponding intake valve is going to open)

The crank sensor, on your engine, is right above the oil filter. It gives the PCM the crank reference for initial spark timing.

Alex Kurdian · Post by **Alex Kurdian** » Thu Feb 16, 2012 7:36 pm

occasional demons wrote:
Alex Kurdian wrote:
Is the crank shaft sensor different than the cam sensor?
Yes. The cam sensor reads the cam position, and after start up, controls the injector timing sequence. (So the injector only pulses when the corresponding intake valve is going to open)

The crank sensor, on your engine, is right above the oil filter. It gives the PCM the crank reference for initial spark timing.

Ahhh...thanx Bill I replaced the Cam sensor when I did my timing belt as it was leaking pretty bad...

Is it worth just replacing the Crank sensor as a precautionary measure on a car 10 years old ? 130,000KM on the clock

Post by **occasional demons** » Thu Feb 16, 2012 7:47 pm

It's up to you, but I have 286,500 + km on mine. Electrical stuff... it will last until it dies. . A new one may not last as long as the original, it's just the way it is. I guess it depends on the cost, vs peace of mind.

Alex Kurdian · Post by **Alex Kurdian** » Thu Feb 16, 2012 7:53 pm

Fair call mate...I'll just leave it then ...Why wouldn't the new one last as long ?

Post by **occasional demons** » Thu Feb 16, 2012 7:59 pm

It may, it may not. There is just no real way to know. Some die well before 100,000 miles, and others outlast the engine.