1990 W250, 255k miles, bone stock, no mods.

First a little history:

This engine has always started on the very first crank. The other day I let a friend borrow the truck to move some stuff. She drove it to her house, loaded it up with her stuff, and then I get a phone call from her saying it wont start. I thought she must have run it out of fuel. She said it was at 1/4 tank, but her driveway is a hill, so I still thought she might have sucked in a little air.

About 3 hours later I went there with 5 gallons of fuel and a can of ether. I put the fuel in, opened a few injector lines, gave it a shot of ether, and it fired right up. I shut it off, and restarted a few times, and it seemed back to normal. Every time starting on the first crank.

She then went about with her moving, with about 10 miles of driving, and then I get a call at 11pm, she is at a gas station and it wont start. I drive there and do the same routine I did earlier in the day (open injectors, pump primer, ether, etc.), but now it wont restart. After many tries nothing was happening. I remembered I had a spare fuel filter behind the seat, so I filled it with fuel and put it in. Then the engine started the very next try.

I was feeling confident that I had now solved the problem (plugged filter). But over the last few days it started normally, but I didnt drive it.
Today it started normally and I drove about 1 mile to a neighbors house, shut it off, and now it wont restart.

Ive searched the forums and tried most everything suggested.

There is 12 volts at the fuel solenoid.
When I open the injectors and crank the engine, I get little spurts of fuel.
Ive pumped the primer until fuel comes out the bleed screw.
Ive checked all the lines with a flashlight to look for cracks or signs of leakage.
Ive greased the fuel heater connector.
Ive unscrewed and reinstalled the filter, It is always full of fuel. This filter has about 5 miles driven on it, so I really doubt it could be plugged.
when I pump the primer lever, I feel resistance for about five pumps, then it starts to feel like it is no longer pumping....if I wait a few minutes, I can then get 5 more good pump strokes, and so on.

I give it a little ether to help it get started but its just not getting fuel.

Its acting like it is sucking air/losing prime. It runs fine, but wont re-start minutes after shutting off.

Im starting to suspect the lift pump, but I want to be sure before I start throwing parts at it. Any ideas?

 

Mine got hard to start and it turned out to be a rusted fuel line. Was letting in enough air to cause hard starts but would run fine while running.

 

might be an electrical issue, i drove my truck somewhere and it was fine. shut it off and fired right back up, went to wawa then and shut it off, got my stuff came out and it had nothing. fusible link was the culprit

 

I've had that prob. twice. Run the motor to operating temp. then shut it off and try to restart. If it wont restart, which it prob. won't, poor cool water over the IP for a couple minutes. Then try to restart. If it starts your IP is about dead. Wanna told me about that trick and unfortunately it has worked twice for me.

 

Sounds like it's time for a new lift pump.

 

My truck was doing the same thing.

Thats where I'd start. It fixed my troubles.

 

At the gas station, how much gas did she put in it? This is why you don't let anyone use your diesel truck, let alone a female.

 

Thanks everyone....

No she didnt put gasoline in it.
Before giving it to her I made sure she knew repeatedly that it was diesel.

This doesnt seem to be an engine-temperature related issue, since it still wont start with a cold engine.

Is there any way to know if a lift pump is dead other than replacing it?
The primer lever feels like it works for a few pumps, and it pushes fuel out the bleed screw.
When I open the injectors and crank the engine I get dribbles and spurts, but it doesnt shoot fuel everywhere.

Is there anything else electrical that could prevent it from starting other than the fuel solenoid?

 

No. If you want to rule it out, gut it. Gut it= remove it, remove spring and plunger from solenoid, reinstall the solenoid. No more key off, you would have to use the mechanical kill lever on the side of the injection pump. This could just be temporary to rule out a faulty solenoid.

Best way to test the lift pump is with a tapped banjo bolt post filter and pressure gauge to check pressure. 3-5psi and some I've read will attain a super healthy 7psi.

 

Every time I read/hear of gas in diesel episodes, I think of the time I watched a yuppy lady at the pumps pumping a 1-ton Ford/Diesel U-HAUL truck full of un-leaded gas; there were about a dozen big DIESEL FUEL ONLY stickers on and around the fuel-tank.


Having had several bad experiences from being a good Samaritan and sticking my nose where it wasn't appreciated, I just let her pump away and kept my nose to my own business.

 

In the absence of a proper gauge, you can remove the little bleeder-screw that is in the out-board side of the fuel-filter and watch it while someone bumps the starter; it would be best to un-plug the wire from the shut-down solenoid while performing this experiment.

A healthy lift-pump will near drown you with fuel.



YES, there are about a dozen other electrical issues that can cause poor running or a no-start, but all of them eventually wind up at the fuel-solenoid.


Turn the key to RUN position and see if you have fire at the solenoid with a test-light; then, with the wire un-plugged, watch what the light does while someone cranks the engine.


If you have fire at the wire, then GUT the solenoid as suggested, AFTER FIRST checking the lift-pump pressure.