Engine dies - but why?

[Marky Dissod]

Spraying some electrical contact cleaner on them can't hurt.

 

[Jobi-Wan Kenobi]

Well what I did Saturday cleaning out the PCM connector cavities and the connectors didn't fix the issue. The engine died on me tonight while I was in town and had trouble starting again. We're definitely losing ignition power somewhere because just as I was going to fiddle around under the hood I heard something go through a power-up cycle and then it started fine.

@Marky Dissod yea I cleaned everything up with contact cleaner.

 

[wjburken]

Had a co-worker have issues last week with his vehicle just dying while he drove it and it turned out to be the crank position sensor. This was on a Volkswagen Jetta though. Would think something like that would throw a code, but just wanted to put that out there.

 

[nonickatall]

I would made a very simple Test. If your engine not starts, go to your exhaust and smell. If it's smell like no burned petrol, then you have a problem with your ignition. If it smells burned, you have a problem with less fuel or less fuel pressure. If its smells like nothing, then you have no ignition and no fuel, which can be for example the crankshaft sensor like wjburken wrote.

 

[Jobi-Wan Kenobi]

I've checked codes a couple times and never had anything show up for crank position sensor. A past vehicle I had though was pretty famous for sensor failure and usually wouldn't throw a code for it either. But the failed sensor would cause the engine to shut down after the engine was hot with the sensor heat soaked. It wouldn't start again until things cooled off a bit but would shut down again when the sensor started getting hot again.

 

[nonickatall]

It can fail a lot, what leads into an unexpected engine stop. For example the fuel pump, a clogged fuel filter (if you have one). A bad oxygen sensor, mass problems, a defect pcm, and so on.

Again, if your car will not start, get on your exhaust and smell. That was no joke....

 

[iamdub]

Well what I did Saturday cleaning out the PCM connector cavities and the connectors didn't fix the issue. The engine died on me tonight while I was in town and had trouble starting again. We're definitely losing ignition power somewhere because just as I was going to fiddle around under the hood I heard something go through a power-up cycle and then it started fine.

@Marky Dissod yea I cleaned everything up with contact cleaner.

I don't recall at the moment, but did you knock around with a rubber mallet or hammer handle or anything similar? With it idling, remove the cover for the fuse center and tap on relays and fuses, etc. Maybe try to pull up, push down and wiggle the whole tray.

 

[Jobi-Wan Kenobi]

@iamdub I didn't use a mallet or hammer handle. But I did have the shield of the PCM and was pounding on it a bit with my fist and just trying to shake it in it's mount. I didn't do any of this to the fuses but can try it.

Was thinking about this earlier and why it only seems to happen in town. When it happens I've been in town doing errands and such and the issue actually occurs when its been sitting for a while (maybe 20 minutes or so). But I can drive to work and back home the rest of the week without issue (only a 20 minute drive though). I haven't figured out yet either if I can drive for extended periods without trouble.

 

[iamdub]

@iamdub I didn't use a mallet or hammer handle. But I did have the shield of the PCM and was pounding on it a bit with my fist and just trying to shake it in it's mount. I didn't do any of this to the fuses but can try it.

Was thinking about this earlier and why it only seems to happen in town. When it happens I've been in town doing errands and such and the issue actually occurs when its been sitting for a while (maybe 20 minutes or so). But I can drive to work and back home the rest of the week without issue (only a 20 minute drive though). I haven't figured out yet either if I can drive for extended periods without trouble.

Sounds like it's related to temperature. Engine bay gets hot during the drive into town then you park and everything heat soaks. You go to start it again minutes later to run the next errand and it acts up. Maybe your drive to and from work doesn't require multiple stop-starts?

 

[Jobi-Wan Kenobi]

@iamdub no, I'm in a pretty rural area so minimal traffic and no driving through town. Aside from the one time it shut off on me in town a couple weeks ago I haven't had trouble driving around town either so maybe the fan is able to produce enough air flow during the city driving while I'm at intersections or driving through parking lots.

 

[wjburken]

You have no other choice now that you have surpassed the 50th post mark on this issue without a resolution…….. let the spending begin!

 

[Jobi-Wan Kenobi]

@wjburken not even sure what the opening shot should really be.

 

[PG01]

@wjburken not even sure what the opening shot should really be.

I don’t know if I missed it but you def checked your positives and grounds? To and from battry?
Start run relay? Check all relays? Etc?

 

[Jobi-Wan Kenobi]

@PG01 battery connections are clean and tight. I haven't put eyes on the battery ground to the frame yet (or the engine or wherever it goes) and it probably wouldn't hurt to clean up the frame ground that's under the drivers door.

 

[iamdub]

...battery connections are clean and tight. I haven't put eyes on the battery ground to the frame yet (or the engine or wherever it goes) and it probably wouldn't hurt to clean up the frame ground that's under the drivers door.

Well, damn. This is one of the first steps! Check that main ground on the other end where it bolts to the engine block, a few inches behind the power steering pump.


*EDIT* I'm a dumbass.

 

[Fless]

Well, damn. This is one of the first steps! Check that ground on the front of the passenger side cylinder head. It's the easiest to get to.


It took way too long to find this pic off the 'net. Ignore the blue aftermarket wire. The factory ground is the black 4 gauge with the exposed copper. It's just inches away from the oil fill neck:

View attachment 407498

Interesting. I was curious enough about this to go look at mine, and it's not there on my L59. And the oil dipstick on mine is closer to the firewall.

 

[PG01]

Interesting. I was curious enough about this to go look at mine, and it's not there on my L59. And the oil dipstick on mine is closer to the firewall.

View attachment 407506

Check the other head.ain’t the battery on ds in NBS? I forgot how mine was setup but I’m pretty sure about battery placement…. Little red junction block for the positive too?

 

[Fless]

Check the other head.ain’t the battery on ds in NBS? I forgot how mine was setup but I’m pretty sure about battery placement…. Little red junction block for the positive too?

Yes, red junction box for the positive, and battery on DS. I think the main (fat) ground goes down to near the starter.

 

[PG01]

Yes, red junction box for the positive, and battery on DS. I think the main (fat) ground goes down to near the starter.

I used to have a ground schematic for the nbs and nnbs but I think I deleted it….oh well

 

[Fless]

I used to have a ground schematic for the nbs and nnbs but I think I deleted it….oh well

I have the one for NBS from the Upfitter's Guide.