injector pump failure?

[DaveP]

Started my 350 dozer today and it started just fine. I did add 5 gallons fuel to the tank. Backed her up and started forward down the driveway and got about a hundred feet before she died. Would not start again. I'm getting fuel to the injector pump, it squirts out with good flow when cranking. But am not getting any fuel to the injectors or back on the return line.

Do I have a pump failure? I do not know how the pump is driven, gears, chain, belt? Could that be the issue? I can get her started with starting fluid sprayed at the intake, but dies as soon at I stop spraying.

Thanks for the help.

[jdemaris]

Do I have a pump failure? I do not know how the pump is driven, gears, chain, belt? Could that be the issue? I can get her started with starting fluid sprayed at the intake, but dies as soon at I stop spraying.

Thanks for the help.

I don't know what vintage your 350 has and therefore don't know what pump it has.

They are use gear drive to the pump with some sort of shear mechanism in-between.

The early CD pumps use three hollow shear bolts where the pump shaft attaches to the timing gear. Later DB and JDB pumps use a special shaft with a narrow spot that will snap in half if the pump turns too hard.

Regardless if you broke shear bolts or a shear shaft- the pump is probably seized. It it's a C pump - no new parts are available to fix. If it's a DB or JDB pump - the parts ARE available. Machines with bad C pumps usually get retrofitted with later style pumps.

[DaveP]

The pump appears to have either been rebuilt or replaced as some point in the past. It has a Sierra Injector Inc. Reno NV sticker on it. So, I'll need to pull the cover off in front of the injector to see if there is a shear pin?

How do I insert a picture?[/img]

[DaveP]

figured out the photo upload. Hope these help with my dilemma.

[jdemaris]

figured out the photo upload. Hope these help with my dilemma.

That's a later DB/JDB pump and all parts are available. There is no shear pin. The driveshaft inside the pump has a narrow spot designed to break if the pump turns hard. You need to ascertain if the pump is actually turning or not. Take the little rectangular timing window off the side of the pump via the two little screws. Then turn the engine over. If half of what you see inside that window is turning - the pump IS turning. If you see nothing moving at all - the pump is seized and the shaft is broken.

[DaveP]

Thanks jdemaris, that really helped. took the timing plate off and turned her over, nothing turns or moves inside . Did a little more cleaning and found an info plate.

Is this something I can rebuild myself? I am a bit of a tinkerer. Will I need a manual to show me how to reassemble? Or is it best to let a shop handle it?

Who would you recommend for parts, or to rebuild?