How does HMMWV shut down? Fuel shut off solenoid questions.

[nikojo]

Just wanted to confirm the way the HMMWV shuts down is by de-energizing the fuel shut off solenoid on the injection pump??

I'm assuming this as there are no other electric parts other than glow plugs and starter on startup. But once started there is nothing else electrical keeping it going??

Also, how often does the fuel shut off solenoid need to be serviced/replaced?

Is it a good idea to replace it to avoid future issues?

Is it easy to service in the field if it goes bad?

How do you troubleshoot it's function other than making sure it is getting 24V? My understanding is that it is a mechanical part that is activated by the solenoid. I have this from one of the manuals but other than listening for a 'click' it doesn't look like there is much more. Maybe that is it.

 

[papakb]

When the START switch is toggled the #54 wire to the top of the IP powers up and this opens the solenoid and allows fuel to flow and the engine to run. Removing that power closes the solenoid and this shuts off fuel flow and the engine stops. There is no air flow control on a diesel engine to accomplish this like there is an a gas engine.

 

[Mainsail]

Just wanted to confirm the way the HMMWV shuts down is by de-energizing the fuel shut off solenoid on the injection pump??

It's not on, it's in; under a cover.

I had one fail in my M1009 when I was 30 mins from the house, and cost me $400 or so to have it towed.

Mine had anti-tamper torx screws on the cover, but not all of the M1009s did so you might take a look.

There is no good work-around if it fails in the field. I suppose you could take the cover off and figure out a way to wire it open, but then the only way to shut the engine off is to pinch a fuel line- which is doable on the M1009 but not sure about the HMMWV.

The good thing is they don't often fail.

 

[Mogman]

The HMMWV does have the 5 point security screws, be very careful when messing with the IP, I have read that the top cover can be incorrectly installed causing a runaway engine, but have not seen this myself.
The run solenoids are pretty reliable, not one of the things I would be concerned about but I guess it would not hurt to have one in the spares box along with the correct bit.

 

[nikojo]

I wonder if there is a way to 'bypass' with some tubing in an emergency? Seems like there is an intake hose barb and and return. Don't know how it gets into the actual IP and if there is a way to hook up a hose there.

And if that's the case I wonder if you could just set up something with a manual valve the you can open and close similar to the valve for the fuel/water separator.

Seems like this is a vulnerability that isn't necessary. Obviously it's another step to manually shut off the vehicle by getting out and turning valve.

Obviously not a big problem as I haven't seen many posts regarding failures.

 

[Mullaney]

I wonder if there is a way to 'bypass' with some tubing in an emergency? Seems like there is an intake hose barb and and return. Don't know how it gets into the actual IP and if there is a way to hook up a hose there.

And if that's the case I wonder if you could just set up something with a manual valve the you can open and close similar to the valve for the fuel/water separator.

Seems like this is a vulnerability that isn't necessary. Obviously it's another step to manually shut off the vehicle by getting out and turning valve.

Obviously not a big problem as I haven't seen many posts regarding failures.

.
And if you decide on a manual valve in the fuel supply - you will have created yourself a good anti-theft device for your truck. Just don't contract Alzheimer's or you will wonder why your truck won't start...

 

[nikojo]

.
And if you decide on a manual valve in the fuel supply - you will have created yourself a good anti-theft device for your truck. Just don't contract Alzheimer's or you will wonder why your truck won't start...

Good point. Could be anti theft from myself lol.

 

[Mogman]

Well the solenoid trips a lever in the governor housing on the IP.
I would not be surprised if Roosa Master did build pumps with mechanical shut down but I cannot ever remember seeing one.
I think allot of other things are going to fail on you before the IP shutdown solenoid......
But no you cannot simply install a valve somewhere to bypass the shut down solenoid.

 

[Mainsail]

This is what it looks like in the M1009 with a 6.2 NA:

 

[Mogman]

This is what it looks like in the M1009 with a 6.2 NA:

View attachment 887927

View attachment 887928

The small one is the cold advance, man it looks like a bunch of metal "filings" bunched up around the run solenoid plunger...

 

[Guyfang]

All Roosa IP's are built like this. Or very close. Gen sets the same. And yes, there is a way around it. Provided you have replaced the no tamper screws, you remove the IP top. Using some wire and cussing a lot, you wire the push valve into the on position. Then you put the top back on. Start the truck. Of course, this opens a whole can of worms in the stopping of the truck. Back 40-45 years ago, we had a very big, and important NATO evaluation. Flunking it, often lead Battery Commanders pondering what they wanted to do after being passed over for promotion twice. So when we had a failure of this kind, I tore the top off the IP, (back then, there were no, no tamper screws) to see what I might do to fix it. One of my guys, probably a car thief, hit on the idea right off.

 

[springer1981]

This is what it looks like in the M1009 with a 6.2 NA:

View attachment 887927

View attachment 887928

Posts with questions like these, and pictures like this, make me think of ways to solve problems that don't exist

I downloaded the second picture and marked it up. The gist of it starts off making a new plunger OR an add on piece to the end of the plunger (the red part in the picture below). Extending the plunger and adding a larger disc of steel would allow the plunger to alternatively be operated by a external mechanical magnet instead of the internal electronic magnet. The external magnet could be moved closer to the IP solenoid housing via a cable to the dash, like the vent cables for example. This would allow you to operate the solenoid without power to the coil, from inside the vehicle. Essentially a manual override.

The magnet and plunger eliminates the need to add any holes to the housing and introducing potential fuel leaks.

Operation: In the event of a electronic failure, push the cable in moving the magnet closer causing the plunger to move and open the fuel to the IP. Pull the same cable out, moving the magnet farther away and it causes the plunger to release and close the fuel to the IP.

 

[TOBASH]

I wonder if there is a way to 'bypass' with some tubing in an emergency? Seems like there is an intake hose barb and and return. Don't know how it gets into the actual IP and if there is a way to hook up a hose there.

And if that's the case I wonder if you could just set up something with a manual valve the you can open and close similar to the valve for the fuel/water separator.

Seems like this is a vulnerability that isn't necessary. Obviously it's another step to manually shut off the vehicle by getting out and turning valve.

Obviously not a big problem as I haven't seen many posts regarding failures.

If you bypass, make sure you include an easily accessible ball valve as a check valve to stop fuel flow.

 

[Mogman]

And you must seal that cable, there is fuel pressure there.

 

[nikojo]

Posts with questions like these, and pictures like this, make me think of ways to solve problems that don't exist

I think this is half of what we do on most forums LOL.

Your idea gave me another idea. I don't want to make it more complicated with cables, and plungers, etc.

It looks like at least the 'lever' can be 'locked' in open position. So maybe do that and then the other thing left is how to run or loop the fuel line with a valve to cut it on and off.

Does anyone have more detail on what the lever does or how it works? Does it activate a valve in the fuel line?

 

[nikojo]

If you bypass, make sure you include an easily accessible ball valve as a check valve to stop fuel flow.

Where would you put the check valve and why do you need it?

I picture the solenoid/fuel disconnect essentially the same as a manual cutoff. So why is the ball valve necessary?

 

[nikojo]

Here is schematic of IP.

Looks like 19 is hose bringing fuel from filter and 13 is check valve with 10 hose for fuel return.

So the hose loop/manual valve would have to be spliced into 19 somewhere??

 

[Barrman]

I have been trying to figure out a way to run and stop the engine without electricity as well. Keep the ideas coming.

 

[Mogman]

OK, so you figure out how to "run" the engine without electricity, so how are you going to start it??????
If you have enough battery to start it you have enough power to run it for MANY hours if you conserve what you have.
AFAIK no modern automatic transmission has a rear pump, for those that were not there we used to be able to pull start some vehicles with automatic transmissions, the old powerglide for one because it had a rear pump as well as a front pump so it would build oil pressure and would engage the clutches when being pulled...

 

[Mogman]

What possible scenario would justify all that work? if a solenoid failure is the only motivation then just carry a spare.
I will now get off my soap box and retire for the evening