IP Problems - won't shut off

[bmiszuk]

I'm at the end of my rope. I just spent another evening and don't have a driveable truck yet.

I recently replaced the throttle shaft seals and bushings on my IP. The replacement went pretty smooth but it looks like I put something together wrong. Now the truck won't shut off. I removed the top cover and checked to see if the shutoff "hook" is catching inside the pump. It is. When I connect the red wire, I get a spark but no significant click.

Anyone know enough about IP internals to tell me what I might have done wrong? To remove the throttle shaft, I had to remove the shaft that goes front to back inside the IP. Perhaps I got something wrong there...

I know I should just buy a rebuilt pump, but now's not the time for that. I need to buy a little more time on this one if I can.

Thanks.

[john8662]

Check that the little guide clip went over the stud that you insert from the back. The stud rides in between the clip (camera is dead right now, or I'd snap ya a pic).

How well does the linkage move when manually moving it?

[bmiszuk]

Hi John,

The linkage inside moves freely with the top cover off, is that what you mean?

[dieseldummy]

Make sure that you didn't get the spring on the end of the governor linkage over the "shoe" that it rides on. Other than that if you are pushing the shutoff mechanism all the way forward than getting the cover on correct it should work.

[john8662]

This is the one I was thinking of...

http://www.thedieselpageforums.com/photopost/data/506/P1010001b.jpg

[bmiszuk]

The arrow is pointing to part of a little spring, right? (I'm not in a place where I could go look at mine right now.) If so, then yes I have the leg of that spring on top of the shaft like that.

Can you explain how the shutoff works? The solonoid needs power to engage and I assume to allow the engine to run. So by default, with no power applied, no fuel can flow, right?

I don't quite understand how moving the solonoid arm shuts off fuel to the IP.

Thanks.

[bmiszuk]

I just went out to the garage to work on the truck again. The IP is still mounted, though I had left the cover just sitting on it loosely. Now the IP has no fuel in it. It apparently leaked out somewhere..?? The original reason I pulled the pump was that the engine valley was full of fuel and it looked like the throttle shaft seals were leaking. Now I don't know if my initial diagnosis was correct.

Is there anything wrong with one of these for my '83? I'm getting desperate, and we need the vehicle.

http://cgi.ebay.com/ebaymotors/6-2-HMMWV-DIESEL-STANADYNE-INJECTION-PUMP-4523_W0QQcmdZViewItemQQcategoryZ33555QQitemZ807555 0369QQrdZ1

[john8662]

Bob,

Now you've witnessed why it's soo important to not have any fuel leaks, as the fuel can actually be allowed to return to the tank. That's what makes it so hard to start an engine with an air leak...

Take a look at the linkage again... I'm drawing a blank, don't do much tinkering with the internals of these things...

[BobND]

Can you explain how the shutoff works? The solonoid needs power to engage and I assume to allow the engine to run. So by default, with no power applied, no fuel can flow, right?

I don't quite understand how moving the solonoid arm shuts off fuel to the IP.

Thanks.


Using jumper wires, with the pump cover removed, verify that the solenoid is operating the shutoff lever. (Observe polarity. SOME automotive solenoids have a spike suppression diode built in, and will be damaged if powered up with polarity opposite that of the vehicle they're installed on.) Powered up, the arm should swing one way, remove power, a spring (next to the solenoid in the pump cover) should swing the lever to the "fuel shutoff position"

When the cover is properly installed on the IP, when the lever is pulled to the "shutoff" position, it catches a "tab", and the fuel metering valve gets rotated to the "shutoff" position.

The lever on the fuel metering valve snaps onto the valve, and COULD possibly be worn, or loose, or out of position, so the metering valve is not being rotated the the "shutoff" position.

It is possible to drop the pump cover in place without the shutoff lever sliding in place next to the "tab", which can cause "engine runaway" because it can jam up the operation of the governor when the cover is tightened down.

There is a special tool, more or less a bent wire, that holds things in place while the cover is lowered in place, and is then withdrawn.

I don't have one of those, but, using jumper wires, I energize the fuel shutoff solenoid while I lower the cover in place, then install and snug the three bolts while it is still energized.

With the lever hanging down from the cover held in the "RUN" position by the energized solenoid, it is easy to drop the IP top cover in place, and any chance of jamming up the governor linkage is eliminated.

Then, you can connect and disconnect one of the jumper wires, and hear the the mechaism inside the pump is actually moving, and not jammed.