Priming a dry Cummins PT IP

[HVYMTL]

I've been troubleshooting a loss of prime in my M818 after sitting a day or so.
I can get it started with excessive cranking and a shot of ether, but I'd rather save the starter/batteries & engine undue stress. From searching this forum, I've seen reference to manually priming the fuel pump/injector pump by removing a plug on the top of the pump, and filling it with diesel. Unfortunately descriptions vary, and people use different terminology for the same part in question. I've looked thru the TMs, and it only mention use of the manual (dash mounted) primer pump.
I've attached a picture with 3 arrow designations; A,B & C. Could someone clarify this for me? Per the TM, I see that item "C" is a filter assembly, I'm really questioning what the other 2 are.
Thanks

 

[area52]

I am not sure on what A and B are but have you checked the transfer switch by the drivers seat to see if that is where you are sucking air in at? Check the fuel line hoses for cracks and I bet that is where you are losing prime.

 

[doghead]

Other places to look for air leaks are the , IP screen washer(identified as C in the picture posted above), fuel filter top bolt washer, rubber fuel line between the filter and the IP. The tank selector valves are commonly the problem also.

The pump on the dash, is for the cold start assist, fuel pressure.

 

[73m819]

check the top of the fuel filter, if that little gasket on top of the filter houseing is out of place, it will suck air

DH types faster then i do

 

[Hammer]

A small amount of air pressure to one tank at a time will find the leak(s), fast!

 

[WillWagner]

Ditto on all of the above. Your engine should not lose it's prime, even with sitting for years.

 

[98hd]

Pull A and fill w/ fuel. Give it a good shot of ether. It should fire and die. Give it another shot of ether and when she fires work the pedal. It should keep running on the 2nd or 3rd try.

 

[DOCUSN1]

Take off your fuel filter canister and make shure your filter is good and the can is clean. Then place your filter if it is ok or a new one in and fill the can up to the top with diesel fuel put can back on and tighten up make shure its lined up and gaskets are ok. After that make shure everything is ok between the can and the pump and everything is tight. Make shure your batts are charged up good. Next try starting it up with a snoot of ether while it is spinning over at max speed. If it fires up and runs for a min and stalls out or quits, check the fuel can if it is empty your problems are from the can back if it is full or does not stall and wont start right the next day then your problems are at the can forward. Are you sure your batteries are good ? 1 bad one and it will make for tough starting. Cummins 855's like to be spun over good to provide a hot compresion to start. Let us know how you make out. Mark PS I have been the victim of a bad tank switch valve before pick one side to use and leave it alone or in my book get rid of it.

 

[DOCUSN1]

Oh btw if you take off C in your pic there will be a filter and sping under that cap. The other thing behind hit sticking up out of your pump is your manual overide, is it wet around that ?

 

[Stan]

DOCUSN1, if you get rid of the tank selector valve did you just tee the lines together or what?

 

[HVYMTL]

I am not sure on what A and B are but have you checked the transfer switch by the drivers seat to see if that is where you are sucking air in at? Check the fuel line hoses for cracks and I bet that is where you are losing prime.

I'm suspecting it is the tank transfer switch, since the hoses to & from look newer. Will bypass one tank supply & return when it stops raining here in NY. BTW, I did research this topic, and a few posts referenced what I needed to know, except there were no pictures, and everyone unfortunately has their own description...same thing, different nomenclature.
Thanks,
Craig

 

[Hammer]

Trust me, a few pounds of air pressure, and you will find the leaks. Very easy and very fast.
I pull one of the small lines that go into the tank at the front and back. I put the air pressure into the fuel tank right there, and check for leaks.
There will be a vent for the air up near the passenger side of the motor. Nothing to worry about.
If you have a leak, you will see it instantly. Switch the valve around and check the other tank as well.

 

[HVYMTL]

Other places to look for air leaks are the , IP screen washer(identified as C in the picture posted above), fuel filter top bolt washer, rubber fuel line between the filter and the IP. The tank selector valves are commonly the problem also.

The pump on the dash, is for the cold start assist, fuel pressure.

I've checked all of the above except item "C". Tried to loosen it with the biggest screwdriver I have, but wouldn't even budge. I think I will have to get
an identical thickness of steel bar (same as slot clearance) and an adjustable or vise grips to apply torque to it. I'm beginning to think the fuel tank transfer switch is at fault, but in the meantime, will also replace the primary feed line from the water/filter seperator to the Injector Pump.
Thanks for your advise,
Craig

 

[HVYMTL]

check the top of the fuel filter, if that little gasket on top of the filter houseing is out of place, it will suck air

DH types faster then i do

Checked and replaced....problem still exsists....even though the concave square washer was not perfectly aligned with its respective mating recess.

 

[HVYMTL]

Pull A and fill w/ fuel. Give it a good shot of ether. It should fire and die. Give it another shot of ether and when she fires work the pedal. It should keep running on the 2nd or 3rd try.

You are the Man!!
That is exactly what I was looking for.
Thanks,
Craig

 

[HVYMTL]

Take off your fuel filter canister and make shure your filter is good and the can is clean. Then place your filter if it is ok or a new one in and fill the can up to the top with diesel fuel put can back on and tighten up make shure its lined up and gaskets are ok. After that make shure everything is ok between the can and the pump and everything is tight. Make shure your batts are charged up good. Next try starting it up with a snoot of ether while it is spinning over at max speed. If it fires up and runs for a min and stalls out or quits, check the fuel can if it is empty your problems are from the can back if it is full or does not stall and wont start right the next day then your problems are at the can forward. Are you sure your batteries are good ? 1 bad one and it will make for tough starting. Cummins 855's like to be spun over good to provide a hot compresion to start. Let us know how you make out. Mark PS I have been the victim of a bad tank switch valve before pick one side to use and leave it alone or in my book get rid of it.

Excellent diagnostic!! This will point me in the right direction. After a while of troubleshooting, most people including myself, become overwhelmed, and this is when you loose sight of the simpler techniques.... I'm working all around (the problem), and can't converge on the culprit....but I will eventually get there, thanks to the great responses from this group.
BTW, the batteries are crankin'...just don't want to kill them.
Thanks,
Craig

 

[HVYMTL]

Oh btw if you take off C in your pic there will be a filter and sping under that cap. The other thing behind hit sticking up out of your pump is your manual overide, is it wet around that ?

Working on getting "C" loosened. The manual override was turned in fully CW to bypass the fuel shutoff solenoid. Electrical signal is there when in "RUN" position, but couldn't tell if it was actuating open, so I put the knurled
bypass into its present position and went on. There is no apparent leak around this adjustment valve.
Thanks again,
Craig

 

[HVYMTL]

A small amount of air pressure to one tank at a time will find the leak(s), fast!

Working on that. Nothing conclusive yet, except that the filler (tank) cap seals are past their prime. Got some sheet rubber to make up new non vented ones.
Thanks for your reply,
Craig

 

[HVYMTL]

Trust me, a few pounds of air pressure, and you will find the leaks. Very easy and very fast.
I pull one of the small lines that go into the tank at the front and back. I put the air pressure into the fuel tank right there, and check for leaks.
There will be a vent for the air up near the passenger side of the motor. Nothing to worry about.
If you have a leak, you will see it instantly. Switch the valve around and check the other tank as well.

Working on that, first I have to get the diesel fuel caps to seal. As is, the tanks will not hold (sustain) any pressure...immediately leaks out with small diesel droplets forced out around the cap seals. Tank is fairly full, not much space for air.
Thanks for the advise,
Craig

 

[HVYMTL]

Ditto on all of the above. Your engine should not lose it's prime, even with sitting for years.

That's great, once I get it fixed, it will continue to work for years. Can't beat that. Thanks for your support,
Craig