12H-T Injection Pump cleaning

[Davaa]

Guys,
I got this spare 12HT injection pump from a local yard which parted out a whole engine. Though they stored the parts inside some dirt and gunk made its way to injection ports and the fuel feed pump opening which was removed already. Do you guys know how I can clean these areas easily without any disassembly. No injection shops around here that I can trust this job.

 

[roscoFJ73]

It is suppose to spotless on the inside and should have had all the ports closed off and kept inside a thick clean plastic bag.
Obviously who ever stored it knows nothing about diesel injection pumps.
The injector valves could probably be removed and flushed out with some diesel.
As for the inside where the feed pump goes, I don't think a speck of soft dust will hurt, but its not good if a piece of hard grit or metal filing got inside.

I would block off the hole and all the other openings. Scrub the outside with engine cleaner till its spotless.
Then I would fill the pump with diesel a few times and try and flush anything that maybe on the inside with diesel.
Maybe you could filter the diesel through a stocking and see what comes out. If lots of gunk comes out, it may need a strip down.

 

[Davaa]

Thanks Rosco, that is exactly what I was planning to do. If I ever put this on an engine I will let it run a bit first before connecting the injector pipes to blow out any remaining gunk from the delivery valves. For the feed pump hole I think I will pour some fresh engine oil to flush out the camshaft area from loose stuff.

 

[roscoFJ73]

I think the inline pumps are bit more tolerant than the rotary pumps. 12HT pumps will be worth their weight in gold one day

 

[Josh Melber]

Hi there, wondering if either of you could give me some advice. I got a 12ht, it had intermittent stalls while driving sometimes at high speed, the stalls seemed to be a fading out as if each cylinder lost its fuel pressure equally. Either way I changed the filters, sedimenter, lift pump, dropped and cleaned tank and replaced the suction piping, blew out lines from lift pump to the tank. Ran good for over 200 miles. I then installed an air to air intercooler kit and 3" exhaust. Ran and sounded pretty good with slight power increase. All of a sudden I was doing 65 and had a fade out stall...i figured i need to turn up the fuel just a touch to compensate for the extra air I'm getting in now and when I went to adjust boost compensator slightly I get a quick start for a split second and then nothing. Tried going back to where I was on screw and same thing, tried adjusting in and out and same thing. I put some air pressure like 4 psi to the boost compensator and it is leaking right out the side of the cap while the four bolts are still in and tight (have not removed)...this clearly seems like either the diaphragm or the spring is bad in the compensator correct??