923A1 Cummins 250 Injection Pump Replacement

[DampLemonade]

Hi all,

I got a little bit of spending money and I think I want to attack replacing the injection pump on my 923 A1. It currently works, it just leaks some diesel from old gaskets (only when running) and the internal part where the tachometer cable threads into is broken so I don't have a working tach. Replacing the pump should fix these annoying little issues.

The TM makes it seem not too scary, but I was wondering if yall had any tips or "gotchas" before I spend a couple thousand on a new pump and then accidentally destroy my engine (or worse, have to get it towed to the local semi truck shop). I've only ever replaced 12v gasoline fuel pumps up until this point.... haha

 

[fuzzytoaster]

The task itself is relatively easy, take it step by step. It doesn't need to be timed or anything. What you will need is special wrenches or make your own. The bolts that keep the IP attached to the air compressor are in terrible spots, one on the back in particular, and Cummins designed a special wrench for it.

 

[DampLemonade]

The task itself is relatively easy, take it step by step. It doesn't need to be timed or anything. What you will need is special wrenches or make your own. The bolts that keep the IP attached to the air compressor are in terrible spots, one on the back in particular, and Cummins designed a special wrench for it.

Another question to resurrect this thread. Im also replacing the canister fuel filter with one of those spin-on kits from mvparts. Are there any special gaskets or washers that go into any of the threaded fuel lines? Specifically the main line from the tank -> filters -> pump? Neither the new pump nor the filter base kit came with gaskets so i'm inclined to believe I can just thread the new hoses on there. I have a set of rubber ones for garden hoses but don't want diesel to eat them away over time. Or should I find some fuel-rated thread tape instead? Just trying to avoid any fuel leaks

 

[Defcon-1]

Another question to resurrect this thread. Im also replacing the canister fuel filter with one of those spin-on kits from mvparts. Are there any special gaskets or washers that go into any of the threaded fuel lines? Specifically the main line from the tank -> filters -> pump? Neither the new pump nor the filter base kit came with gaskets so i'm inclined to believe I can just thread the new hoses on there. I have a set of rubber ones for garden hoses but don't want diesel to eat them away over time. Or should I find some fuel-rated thread tape instead? Just trying to avoid any fuel leaks

I think (someone can jump in on this) that the fluid line connections are AN/JIC fittings (37' flare) on the hose-ends and the correct torque is what makes the seal, but any NPT fitting I wouldn't see how throwing some fuel-rated tape on the threads could hurt. Not sure how your spin-on fuel filter hooks up, but any NPT fitting I would tape/seal and any AN/JIC fitting I would snug/torque. There are many types of NPT cuts, some are better sealing fluid/gas (pressurized and unpressurized) than others, so it depends on your spin-on kit too but tape on NPT fittings can't see an issue. Don't tape AN/JIC flared fittings, (really fine-thread fittings like you find on the air-system lines when a compression flare/nut is used, always straight and not tapered). The correct torque is what makes the seal on those since it is a "metal-to-metal" seal that holds the pressure.

I too am also getting ready to do the fuel-filter spin-on kit (a different type of kit than what you mentioned) so I will be scratching my head too trying to figure out whats the best way to stop potential leaks as well once I open up the can o' worms lol. Post pix when done

 

[DampLemonade]

I think (someone can jump in on this) that the fluid line connections are AN/JIC fittings

I contacted Ken from MVParts to be safe and he said

"The fittings in the kit are either o-ring boss or JIC. Neither of these fittings require any sealant, and sealants shouldn't be used with them, if you do the irony is then they might leak."

So for your setup, unless your filter base uses NPT we should be good to just wrench the new stuff on there. I'll be getting around to do mine in the next few weeks, I'll be sure to post pics of the job