Foxmxrcer

Hey guys,

1990 w250 5spd 350k miles
has fuel screwed turned in 3/4 turn, FSS gutted, 3200 gov spring, piston lift pump, hx35, fuel line is ~1yr old, ~2yr old DAP 5x12(i think) injectors, original injection pump, filled up with fuel about 20 miles prior(was at 1/4tank).

Driving home the other night I had to drop someone off, pulled in and shut the truck off. It restarted fine, pulled out of the driveway in 2nd gear, hammered it a little, and went for 3rd gear. When I pressed the accelerator pedal there was no response at all so I crept up the road as far as I could at idle speed in 3rd and pulled off the road. At first I had thought the throttle linkage fell off, so I shut the truck off and went to check. Everything looked fine, got back in and tried to restart, but it would only crank and not fire. I then flat towed it home with my cherokee . The lift pump is pumping plenty of fuel, the fuel is getting to the pump (removed FSS and primed pump to check). I pulled the oil filler neck and confirmed that the timing gears are spinning when cranking. I tried bleeding cyl 2,3,4 injectors, cyl 2 and 4 didnt even get damp, cyl 3 got slightly damp, So it seems to me that the injection pump is getting fuel, but not delivering it to the injectors. Is this a common way for the pump to fail? Am I missing something else in the circuit? The onyl other possibility I can think of (after talking with Mr.Fusion) is that the front seal of the pump may have blown out, but I dont have an obvious amount of diesel in my oil. I want to pull the filler neck again and try to look with a mirror to confirm that though. If it is a pump issue, Where would you guys recommend getting one? I want to call around for rebuild pricing, and from what I read, I want to stay away from parts store reman units. Pennsicola Diesel has a "rebuilt with Bosch parts" pump available for about 700, but I vaugly remember reading to stay away from that vendor? Any help is appreciated!

Thank you,
Jake

Alec

Is your manual shut off somehow stuck? Can you hear/feel the governor lever moving in the pump if you cycle the accelerator and then the manual shut-off? The pump could have failed catastrophically . . . but then I don't think it would have idled for you at the end. Or, it could be the plunger return springs are broken, but I think you should still be able to get it to start and idle with good feed pressure if that were the case. I never dealt with the vendor you mention, but I, too, remember them having a poor reputation.

Foxmxrcer

The manual shutoff is not stuck, that was one of the first things I checked..... As I've made that mistake before . I finally just got a minute to look at it again, and the throttle does feel a bit lighter then I remember (actuating it by hand at the pump). And I can't hear anything moving, and unfortunately cannot remember what it "normally" sounds like.

bigragu

mhuppertz

Maybe I missed it in your post somewhere, but did you try pulling the plunger out of the shutdown solenoid?

nascar mark

Most likely Inj pump went south then. Yes, they can give up like that. If pump was putting out fuel, "all" lines would be squirting, not just a few.
If front seal was compromised your oil level should be higher and you should smell fuel present in the oil. Another thing to check this is to pull dip stick & clean well...put back in.... let engine sit over night without trying to start. In morning, pull dip stick & see if you have a lighter colored fluid at top of level mark & darker lower, as diesel tends to float to the top after a while.

Foxmxrcer

thanks Augie

I'll try to check in the morning. Been devoting all my time to the house and haven't had time to check anything since posting the original post. The oil does have a slight smell of diesel to it, but it was after I was trying to bleed the system. So it may have been in my nose. Since it's been sitting for a week or so now untouched, I'm sure the diesel has separated. Thanks for the tip!
My fss solenoid has been plungerless for a few years (choke cable manual shut off)

Foxmxrcer

Checked the oil again last night, no obvious sign of diesel. So there goes that theory. I'm going to try and tear the top off the pump this weekend and see if I can see anything.

Foxmxrcer

So, I finally got the pump out today. Planning to ship it to Eric at THD. But I was curious if you folks could answer a question for me. Is this in and out shaft play normal?

https://drive.google.com/file/d/1pHp...w?usp=drivesdk

Alwaysworking

did you check fuel right at the injection pump? i have seen fuel filters plug so tight that nothing will go thru.

Foxmxrcer

Yup, checked it at the fss hole, and the fuel filter is only about 1k old. Pump is already out, getting shipped in. Just curious about the shaft play it had.

Alec

The shaft is supposed to be held forward against its bushing by the return springs. So, no, it should not have any axial play in the shaft.

Foxmxrcer

Thanks man, I figured it wasn't right. It also has about 5-10 minutes of rotational play too. Definitely seems worn out.