Help (RKI)- Fuel pump?

I’ve mostly garaged my M1038 for the past 2-3 years, running it for an hour or so every trip down (about 10 to 15 times a year I’ve come from Maryland to Central Tennessee), oil changed a few times (it’s due). Just got moved in about 3 weeks ago.

My neighbor’s work truck got stuck (we’ve had a LOT of rain lately) and his 15 yo came by to ask and I took the HMMWV over to his house and hauled his truck out of a rut using my winch.

Started reeling in the cable and the engine went from about 1500 RPM to maybe 2500 all on its own and died.

Neighbor’s a diesel mechanic. We both thought “no fuel.”

Put 5 gallons from a jerry can into HMMWV, pressurized tank (I put in a fitting a few years ago), cracked the bleeder screw on the fuel filter until fuel came out, and it started with a little cranking.

Ran fine for about five minutes, did the same revving bit - and died.

Tried pressurizing tank again, wouldn’t start. NO odor of unburned fuel coming from exhaust pipe. NOT pouring out anywhere either.

I have a spare (mechanical) pump SOMEwhere in my garage, the manuals are on a computer that I haven’t unboxed yet, but does this sound familiar?

6.2L NA Detroit diesel.

Thanks in advance.

Norm

Your thinking is correct, that "death rev" is a pretty sure sign of lack of fuel.
You need to be careful pressurizing the tank, too much and you can blow off vent lines.
It could be the lift pump.
When was the last time the fuel filter was changed?

Mogman said:

Your thinking is correct, that "death rev" is a pretty sure sign of lack of fuel.
You need to be careful pressurizing the tank, too much and you can blow off vent lines.
It could be the lift pump.
When was the last time the fuel filter was changed?

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A few years at least.

I trailered this down to TN from MD about four years ago and have put on - MAYBE - 120 miles driving since.

There’s always something. Firing the contractor, seeing lawyers, calling plumbers, electricians, carpenters, drywall installers/finishers/tile guys, flooring people, doing ALL the tongue and groove work myself.

the fuel pump is probably on the order of 10 years or older too (I bought the truck about 9 years ago). I replaced ALL the fuel lines/components from strainer to IP. Have a set of those little green return lines I hope to get around to installing sooner than later.

I know, I know. BAD HMMWV owner, BAD! BAD!

I have a lot of catching up to do not the least of which is send oil out for analysis this time.

Thanks.

Is this the right pump?

I’ve read through several dozen posts here on the NAPA parts (Napa Online won’t load for some reason) and this is all I can find at O’Reilly (plus the other with the crooked lever).

I HAD a spare, I swear I did; ordered it from Amazon years ago, even found a box in the garage with “fuel pump” written on it. No pump inside.

I replaced my pump last year. The pump wasn't the culprit. (Mine was the sock)

I'll send you my good take off if you want.

(The replacement pump i bought from O'Reilly wasn't an exact match either, but it works fine after I rerouted some fuel lines.)

NormB said:

Is this the right pump? (Precision M16209)

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Yes.


Same thing, different source: https://www.ebay.com/itm/176166115720

98G said:

I replaced my pump last year. The pump wasn't the culprit. (Mine was the sock)

I'll send you my good take off if you want.

(The replacement pump i bought from O'Reilly wasn't an exact match either, but it works fine after I rerouted some fuel lines.)

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thank you for the offer.

I’d replaced the sock when I rebuilt the fuel tank/lines/sender/etc. Also put a cutout in the floor to access the tank if needed. At most I’ve probably run a few hundred gallons of diesel through since, flow out the release screw on the filter doesn’t seem to be impeded (I pressurized the system to 5 psi).

Gonna start with the lift pump and go from there.

And, @gringeltaube , I ordered a part through O’Reilly’s. In a perfect world, GM would still have the OEM parts produced here in the US, but as reality most likely has it, every make/model of this pump is cranked out of some Lao Gai (slave labor camp) in mainland China - like where the CCP sent Jack Ma for his arrogance. They’re just boxed differently.

NormB said:

...... every make/model of this pump is cranked out of some Lao Gai (slave labor camp) in mainland China

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Yeah, guess we all would prefer to see "Made with Pride in USA" written on the box....

FWIW:

gringeltaube said:

Yeah, guess we all would prefer to see "Made with Pride in USA" written on the box....

FWIW:
View attachment 947755

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Pride? Nein, Danke.

I prefer gluttony myself.

There is no need to pressurize the fuel tank if the pump is working….

It WAS the fuel pump. Thank God.

Took the better part of 3 hours to change out - and Retired Warhorse was right, no pressurizing needed - who engineered that arrangement should rot in h_ll.

I managed to find my “spare” (at least 8 years old - when I bought it) and have another on order just in case. Just happy it died in my neighbor’s yard instead of on the road somewhere.

Thanks for the tips, advice, kibbutzing.

NormB said:

It WAS the fuel pump. Thank God.

Took the better part of 3 hours to change out - and Retired Warhorse was right, no pressurizing needed - who engineered that arrangement should rot in h_ll.

I managed to find my “spare” (at least 8 years old - when I bought it) and have another on order just in case. Just happy it died in my neighbor’s yard instead of on the road somewhere.

Thanks for the tips, advice, kibbutzing.

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A working pump will pull from the tank and out of the fuel filter in above 10 seconds or less of cranking.

Take a grinder to that outer clamp ring of the dead pump and separate the halves.
See why it failed.

I have had ones where the diaphragm has lost its rubber membrane leaving the reinforcing mesh, ones that just had the diaphragm split, and lately ones that had the lift rod pull through the pump arm.

I'm curious as to how it failed

DREDnot said:

Take a grinder to that outer clamp ring of the dead pump and separate the halves.
See why it failed.

I have had ones where the diaphragm has lost its rubber membrane leaving the reinforcing mesh, ones that just had the diaphragm split, and lately ones that had the lift rod pull through the pump arm.

I'm curious as to how it failed

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I’ll let you know. SO many things to do on the farm yet, I have it on my bench, grinder is in a box. There’s still about 90 boxes to unpack and find places for things like grinders. At least there was space on my bench.