12 valve sat for 15 years...Injection pump wont prime...

Will Carter

Will Carter

Well-Known Member
Joined
Mar 23, 2005
Location
Burlington
The story as told to me...
Old man drops his cigarette behind the seat of his brand new 1996 Cummins with less than 4k on the clock.
Cab goes up in flames.
He parks it in his field to rot away.
Guy I bought it from picked it up at auction 5 or so years ago...

Engine compartment looks show room new less 15 years of dust. Other aspects of the truck seem to verify this story...

Anyway...I've put on a new lift pump and have run new fuel lines (directly to an to an 'auxiliary' tank with fresh fuel. New fuel filter. I'm getting flow upon cranking through the filter and through the injection pump but not a drop out of a delivery valve. When I pump the lift pump by hand I hear a slight 'squeeze' of air or fluid that seems to be coming from the injection pump somewhere. No exterior leaks at the input or output. It seems to 'squeeze' every third pump. Internal fuel pressure regulator or something?
IP cam shaft is turning...

What am I missing?
 
New lift pump? Still no prime? Hmm... Sounds like something in the pump is stuck. Perhaps do some searching on 4btswapsdotcom. Lots of good info and people over there. Of course, there are several good Dodge/Cummins forums as well.
 
I'm guessing this is the truck Matt called me about yesterday- some of these may be repeats, but it's worth being methodical

- I assume your supply/return lines into the aux. tank are both low enough in the fuel level to not be "backward". I reversed my fuel lines one time and could get fuel to the filter, but would never prime the system (residual fuel was juuuust enough to ooze out of the top of the fuel filter bleeder)

- try cracking the caps on the injectors ( leave them tight on the dv side). leave all of them cracked until you get fuel oozing from each while you spin the engine. You'll probably get less air in the injection lines this way than cracking the caps at the dv holders.

- check the overflow valve (pressure regulator) for proper operation; it's located at the return outlet banjo fitting on the front passenger side of the pump... might want to remove and see if there's anything stuck in it (truck would probably run with it clogged anyway)

- as mentioned above, ensure the shutoff lever is fully engaged. probably best if you remove the solenoid and pull it up (if you havent)

-might want to pull off the supply line between filter and pump, and probably the other lines around the lift pump & filter assemblies and ensure that none are clogged.
 
Not the manual cutoff that stone is talking about. Same thing happened to my 12v that he is talking about. Look on the backside of the inj pump and look for the fuel cutoff solienod, they are about $70 at orielys. If you'd like to check it, I have a gutted one if you'd like to try it.
 
where is the truck at will?
 
snappy said:
Not the manual cutoff that stone is talking about. Same thing happened to my 12v that he is talking about. Look on the backside of the inj pump and look for the fuel cutoff solienod, they are about $70 at orielys. If you'd like to check it, I have a gutted one if you'd like to try it.
Click to expand...
hey snap this truck is a p7100 not the ve bosch.they want 250+ for the cut off on this pump and its all external and takes 2 secs to change
 
I've removed the AFC and the solenoid and am operating it by hand. There is no resistance at all on the shut off lever. I thought I remember it having to manually close the plunger when they're working....like you feel a slight detent at the end of the stroke...? It's been a while since I've messed with a Ppump...

Should the 'fuel lever thing' (thing that rides the plate) be coming forward at all when the lever is up (on) and cranking...'cause it's not...
 
Indy Will said:
Should the 'fuel lever thing' (thing that rides the plate) be coming forward at all when the lever is up (on) and cranking...'cause it's not...
Click to expand...

I think that only comes up with RPM and throttle..

I second cracking the lines at the injectors..
 
This ain't my first 12 valve fight.:flipoff2:

I'll worry about injector cracking when my delivery valves are putting eyes out with fuel squirts.

There seems to be a stuck plunger causing the whole rack to stick...
 
Indy Will said:
This ain't my first 12 valve fight.:flipoff2:
I'll worry about injector cracking when my delivery valves are putting eyes out with fuel squirts.
There seems to be a stuck plunger causing the whole rack to stick...
Click to expand...

It was my first 12-valve fight, I punted and brought the pump in for a rebuild...rack was stuck
 
shutoff lever has no felt detent when operated by hand

can you get a screwdriver down through the opening and see if the rack can be moved that way? hahahah

also, did you ever pull off the filter-to-pump supply line and ensure it's not clogged?
 
Is there a trick for removing the 'delivery valve assembly'?
The thing with two studs and nuts holding it in...

I've got two out. The second had some suction from the plunger and was difficult. Don't want to tear up a broken pump any more than it is...
 
rj performance...that is all.
 
Pshht...you guys call yourselves mechanics....





:flipoff2:




So I worked on it for another 3 or 4 hours...kept tearing into it and finally found #4 plunger stuck in the bore pretty solid...little persuading and some PBlaster finally got the rack to free up nicely.
Since I removed all the valves I need to tune the individual line pressures I'm sure. Anybody know if you can do this on the truck or does it need to be on a pump 'dyno' deal?

Coolant looks great and I got the thermostat to cycle what felt like 3 or 4 times...No dead spots while slowly revving to the de-fuel mark...

And yeah yeah...I'm sure it still needs at least a seal kit...but that's one less thing I gotta do to carry on with the project...
 
Since I removed all the valves I need to tune the individual line pressures I'm sure. Anybody know if you can do this on the truck or does it need to be on a pump 'dyno' deal?
Click to expand...


no, unless you turn the actual barrels you do not need to have the pump benched - just throw in the replacement DV's and rock & roll
 
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