Diesel injection pump won't idle

[dkmc]

If anyone knows of a "diesel engine" site or forum where I can post this, please reply...

I have an '89 Mitsubishi Fuso turbo diesel 4cyl. It supposedly has sat for a couple months and when started now, it runs up to
2200-2400 RPM and -will- run faster, but won't idle. It -does- shut off, and the rack in the pump isn't stuck. I was told by people that fix them, sometimes when they sit, "something" "freezes up" inside the govenor, and "a lever" inside the pump bends when the pedal is forced down. I have disassembled the gov. and now know this is not possible, as the throttle lever is spring compensated and only applies limited torque to the govenor parts.
I am very wary of taking it to a pump repair shop, as they seem -very- quick to suggest a "complete rebuild" ($600-800-1600) while skirting my technical questions. I'm wondering if it is a relatively simple repair. Anyone on here with any insight or fuel injection pump background? Any possible
causes for this problem?

Thank you

dkmc

 

[PJGD]

I am not familiar with that injection pump, but I assume it is a Denso or Diesel Kiki (Bosch license) in-line pump. I do not know if it has an "All-speed" governor (throttle lever position controls engine speed through the governor), or a "Min-Max governor (throttle controls rack position everywhere between low idle and high idle). The "freezing up inside the governor" does not sound likely to me unless water got in to corrode things.

Try disconnecting the throttle linkage, then make sure the throttle lever returns to the low idle stop (Perhaps there is a PTO throttle which is over-riding the pedal?). If no improvement, back-off the low idle stop screw and see if that drops the speed. Possibly the low idle screw has been "tampered" with? If that does not help, then the problem likely is within the pump. Before going too far though, I would check to ensure that all other aspects of the fuel system are sound, eg, the fuel filter is not blocked (this can mave unexpected and non-intuitive effects on governing), and the nozzle opening pressures are in the right range (a blown-off tip causing uncontrolled fuelling?). If the problem is in the governor, you will want to check the idle governor spring pre-load and spring rate.

That should point you in the right direction.

PJGD

 

[dkmc]

Thanks for your comments.....
Additional info:
YES it IS a Diesel Kiki inline pump.
I would "say" based on the linkage inside the
govenor, it is an "all speed" type design.
Now the kicker....the throttle lever is against the Idle stop screw. NOTHING looks like it has ever been ajusted or tampered with. I was told this truck was "working and running fine" before trade in 2 months ago.
Ran "out back" and parked till I came along. I suppose blocked fuel filter, or such (whatever could occur "in nature" in 60 days)
is a more believable possibility. When it ran, (2200-2400rpm) it was smooth, and no smoke (no load). It has me really puzzled just WHAT could happen to it while sitting for this time.....??? Rain water/condensate in fuel?
Sudden failure of the idle spring? (It looks fine).

dkmc