She just... died....

[RSchanz]

I was driving home on Saturday evening and at a red light thought the truck seemed like it was idling kind of low and rough but didn't think too much of it. 10 minutes later I was driving downhill put the clutch in getting ready to stop at a stop sign. I rode with the clutch in for like 30 seconds then the engine just died. Electrical stayed on and luckily since I was going downhill I could pull over to a safe area. All of the gauges (stock) looked fine, fuel was nearly full (just topped it off like 15 miles earlier), engine wasn't overheating (its worth noting that it was like 90º which isn't that hot I know but still warm). I popped the hood, everything looked normal, no fluid leaking on the ground everything was fine. I waited like 2 minutes and it wouldn't turn over when trying to start. Waited another 2 minutes started it again and it was fine. I proceeded to drive home another 10 minutes or so and haven't touched it since.

Anyone have any thoughts? The hill is a pretty long downhill so honestly my first thought was that the fuel wasn't getting delivered to the IP. Seems doubtful but it was the best I could come up with. When it was dying I quickly switch to the front tank just as a natural reaction but by the time I did that it was already off. When driving it home I left it on the front tank so I guess its possible the rear tank is problematic.

 

[Cubey]

Perhaps a wonky ignition switch? You said it wouldn't turn over at one point.

 

[Nero]

Check your fuel, make sure a tanker didnt accidentally put gasoline in yhe Diesel tank in the ground.
Also make sure you have power to the fss

 

[Cubey]

Check your fuel, make sure a tanker didnt accidentally put gasoline in yhe Diesel tank in the ground.

If not water, if it has rained heavily recently. My VW got pure water from a gas pump in Arizona last winter, as did everyone else pumping regular. anyone pumping mid grade got 50% water.

 

[rreegg]

had a rough start once and happened to notice the fuel filter was a bit loose and leaking slightly. but agree with others it sounds fuel related

 

[Brian VT]

Clogged fuel filter? Water in fuel (filling station at the bottom of a hill?)? Bad tank selector valve?

 

[mexicanjoe]

if you have too many keys on your keys ring, centrifugal force may cause the keys to shut off ignition- just a thought.

 

[IDIBRONCO]

Did your lift pump crap out?

 

[MtnHaul]

Maybe time to add a fuel pressure gauge to the IP inlet line and see if there is a pressure difference between front and rear tank, or if there is pressure at all. The IP will suck enough fuel to keep going but won't sustain high RPMs very long, at least in my experience.

 

[RSchanz]

Alright, was out of town for work sorry for the delay on this one and thanks for the feedback.\

I turned it on tonight and everything was fine until I pulled the water separator plunger and lots of fluid came out the line and then the truck shut off. Assuming two things, air in the system or an issue with the water separator. The fluid seems like it will flow endlessly so I think it's actually fuel not water, I think I've already emptied the capacity of the separator. I emptied some into an old mason jar so I'll inspect it tomorrow morning. If it is just fuel, whats going on here?

 

[Cubey]

The 83-87 factory water separators mounted on the firewall can let air in due to age of the seals. Try bypassing it and see if it helps.

 

[RSchanz]

I knew that was an issue and the idle did seem a little rough so bypassing it is a good idea. Still curious how it works and why it seems like fuel just flows out when I pull the plunger.

 

[Cubey]

I knew that was an issue and the idle did seem a little rough so bypassing it is a good idea. Still curious how it works and why it seems like fuel just flows out when I pull the plunger.

Because it's a drain on a canister that's full of fuel all of the time. It's a water separating "filter", but not a proper fuel filter, hence it being there as well a spin on fuel filter.

 

[RSchanz]

But I thought the purpose in the plunger was that the water would come out not just the fuel

 

[The_Josh_Bear]

But I thought the purpose in the plunger was that the water would come out not just the fuel

Yes water and diesel don't mix, water is more dense so it sinks. When you open that valve it lets anything inside out, the idea is that you'd drain it just enough to get any water out and close it again. In my experience the water separator almost never needs to be drained. Our work trucks are class B shred trucks, we put a lot of hours on them and we won't have any water in the separators like, ever. I don't know if I've ever seen any water in them. I drain them from time to time but can't remember any water.

The separator is there for bad fuel and leaving your tank sitting mostly empty through hot/cold cycles where the inside of the tank might dew up and get water that way. Another way is if you're burning un-separated WMO as I do sometimes in my rig.