No throttle, then no start

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No throttle, then no start

Postby Foxmxrcer » Wed Dec 05, 2018 7:00 pm

Hey guys, I posted this question on another forum, but it seems to be dead there....

1990 w250 12v 5.9 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 :lol: . 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 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. No, my manual shutoff is not "shut off". 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
Foxmxrcer
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Re: No throttle, then no start

Postby Donkey Kong » Thu Dec 06, 2018 9:41 am

If your VE is toast, try Industrial Injection or THD. They have good VEs. I’m not a VE expert but it could be the tiny fuel metering pin is stuck shut? Try pulling the fuel pin out of the AFC and move throttle slowly. Look down into the AFC and you should see the metering pin move out. Dont go too far, you dont want it to fall in the cavity. If it pushes back in easily then it's probably ok. If it doesnt move at all you may need to pull the throttle shaft assembly to free it up, becase thats where its actuated
Darth Cummins 93 CC W250 NV4500 HX35 350hp 37s 1.5T leafs...its stiff
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Donkey Kong
fuel screw!!!!
 
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Re: No throttle, then no start

Postby PToombs » Thu Dec 06, 2018 5:22 pm

The fuel pin won't make it act like yours does. It should still start even if the pin is stuck.
I'm more of the opinion that the pump crapped out. I had to replace one on a skid steer that had snapped the pump shaft. It would turn over but not start. When I pulled the injector lines off and turned it over it would only pee fuel from #3, a constant stream.
Only other thing I can think of right now is maybe you sheared the key on the pump gear. It was running but poorly because the timing was off, but when you shut it off it's too far out of time to start.
pete

Just enough power to break everything behind the crankshaft.
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Re: No throttle, then no start

Postby spencerdiesel » Fri Dec 07, 2018 10:41 pm

Ive heard a couple guys say its not super uncommon for VEs to break the high pressure spring things :D

Ill admit full ignorance on that
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: No throttle, then no start

Postby PToombs » Sat Dec 08, 2018 8:13 am

Yeah, those springs take a beating in their lifetime. I've never had one or seen it happen, but have read about it several times.
pete

Just enough power to break everything behind the crankshaft.
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