Hi Guys,
My first thread and I am in need of some of the wisdom, I have read about on this site
for a long time.
Have a 1st Gen. 1990 Dodge with the Cummins in it. Owned it for about 10 years. Put about
250k on it. Never had a real problem with it, besides rebuilding the 727 after the tailshaft sheerd off.

NOW I AM STUCK IN MODESTO, Ca with a problem.
Drove on Hwy 99 at about 65 Mph without any problem, suddenly the engine quit in an instant. Will start back up after a little while, seams to have something to do with the
temperature. I am able to drive it for a while, until I put my foot in it a bit more, then it stalls again. Sometimes it will stall after cruising around a parking lot for a few minutes.
My guess is, its the fuel pump shut off solenoid. But maybe the lift pump.
Any of you guys have any ideas, I have about 4 hours of daylight left?
Thanks in advance,
Mike

 

I would be leaning towards the FSS. When did you last do a fuel filter? Also when was the lift pump last swapped?

 

Thanks for your respons.
Have 2 fuel filters on it, changed both within 4k. Checked the factory filter for water, with the
little plunger, only diesel, nothing else.
Lift pump is about 4 years old. But my memory tells me that on a 12 valve first gen, the lift pump is only used when starting the truck. The later 95 and up with the p7100 pump use the
lift pump while driving. Is that correct, or am I remembering it wrong.

 

Clean the terminals that lead to the FSS and see what happens.

First thing I do when I buy one of these truck is clean those terminals, or replace them completely.

 

Both motors would run better with a lift pump but would probably make do without if they had no fuel line air leaks and stay primed.
I am thinking the FSS wire is loose and that is your problem.

 

I agree, either iffy connection or bad fss. Make sure that the wire to the fss is nice and tight and that it has 12 volts with the ignition switched on. If not, try running a wire straight from the battery...Mark

 

Thanks guys, just to make sure I understand what you mean with FSS?
You mean the fuel pump shut off solenoid, correct?
That is the one with the single wire attached, by a factory looking plastic clip on connector, correct?

 

Yes, that is it.

 

It's the one on top of the pump distribution head, just above where all of the injector lines attach to the pump.

 

Thanks guys. Ran a wire direct from the positive battery pole to that connector on the pump.
No go, does not work. With that wire. If I plug the factory wire back in, it starts again.
Don't know why not. Made perfectly sense to me. But it don't work. Don't have a test light to check if there is positive power there, on the factory wire.
Could it be that this wire is supposed to be ground and if you take the ground away,
It shuts the pump off?

 

Did you run it to the connector on the wire ir to the terminal on the fss? It needs to go to the connector on the fss. If it starts with the factory wire, it has 12v. make sure the connection is nice and tight...Mark

 

Tried it one more time with the direct wire to the positive on the battery.
Started now, fuseable link I used had a bad fuse in it.
BUT, still the same problem. When I start driving off, it dies on me after a very short time. Just like before. So it could have not been the power supply or the bad contacts.
What else can it be?

 

Back to fuel restrictions then, maybe….like the fuel filter that you last changed 4 K ago would be a good place to start.

 

I highly doubt this is it, but try leaving the gas cap off, perhaps vacuum build up in the fuel tank?

 

The FSS could still be failing. I would also either replace it, or gut it and use a manual fuel shut off.