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6.5 Shut Off, No Start

Messages
3
Likes
3
Location
Upper Michigan
Thread starter #1
Hey guys, the other day my 6.5 shut off. Was driving and shut off as if someone turned the key off. Well I know that I'm not getting fuel. No voltage to lift pump, but pulled it out to find it did not work after testing it. Put a new one in and still no fuel. The injection pump will kick on but fuel pump wont. Took out the filter and turned on the key after the new pump and the housong did not fill. The Fuel Pump Relay had 12volts to power and ground in the relay....no idea why. NOTE: has a PMD (or FSD) relocation and cooler kit. Mounted up by the intake. Any clues?!?!?!?
 

Jaryd

Love my 6.5
Messages
754
Likes
952
Location
Hodges, SC
#3
You need to move the pmd to behind the front bumper. Clean all your grounds real good and go ahead and put a 1/4” clear return line on the injection pump while your in there.

Leroy Diesel is a site vendor and knows these engines like nobody else and he sells the pmd with heat sink and extension harness. Click his banner at the top of this page and it’ll take you to his site. You might have to wait until his rolls around. If you buy another pmd with heat sink make sure to save your old heat sink
 
Last edited:
Messages
5,605
Likes
577
Location
Rural Clifton, Illinois
#9
You should be able to jumper the lift pump. There is a jumper wire on a 98 in between the under hood fuse box and the firewall.

It is just a little wire with a male or female spade connector. I have been installing a toggle switch with an inline fuse coming off the under hood fuse panel - to that wire on 1996 and newer 6,5's

95 and older need the lift pump relay upgrade.

What brand of lift pump did you buy? If going OEM style - use only a GM or ACDelco. I had no longevity out of any other brand.

A permanently mounted fuel pressure gauge is a very handy thing to have for diagnostics.

Did you test the new pump before installing? New does not mean working - always test new parts before installing them.

I know a guy that installed a new fuel tank sending unit without testing - that's a time waster right there. Same guy also got bit by new but bad seals, bearings, alternators and starters. You'd think he'd learn to test everything possible before installing, but I still forget sometimes.

Jumper the little wire by the fuse box - or just go ahead and install a fused toggle switch as I do for diagnostics and bleeding the fuel filter - or you can go whole hog and get Leroy's lift pump relay upgrade.

The upgrade is not really necessary on 96 and newer, but the heavier wiring certainly does not hurt anything.

Do not change the OPS unless you verified it is bad. To much of a PIA and new parts are not guaranteed to last any longer than your good working old part. I do some parts swapping without verifying, but for the most part I avoid it.

Parts swapping I do - If I have the intake off - I give the engine harness and IP harness a visual. If they look suspect, I just install new harnesses. I am about done with that now. I think I have 2 vehicles left that could use new harnesses.
 

Paveltolz

Доверяй, но проверяй
Messages
2,407
Likes
725
Location
Saratoga Springs, UT
#11
Before buying a bunch of parts that may not solve the issue, do the jump test recommended above.

Jump point for the Lift Pump.
LP Prime 1.JPG

Use one of these two auxiliary power points behind the Underhood Fuse Box to jump power it.
LP Prime 2.JPG

I know the OBD II trucks aren't supposed to need an OPS to run the LP but, my 96 does...just sayin'.
 
Messages
5,605
Likes
577
Location
Rural Clifton, Illinois
#12
If you put the jumper or toggle switch to the jumper wire, you can just leave the lift pump running while doing diagnostics and trying to start.

I also check to make sure I have fuel to the IP. A pressure gauge can do that for you.

You can have voltage to the lift pump but not enough amps to run it. If that would turn out to be the case, I would install Leroys lift pump relay upgrade. Even on a 96 or newer
 
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