Replace Cummins PT fuel pump - Steel Soldiers::Military Vehicles Supersite

NDT · 04-08-2010, 20:29

Here is some info for anyone faced with this task. First of all, the purpose of the Cummins PT pump is to draw diesel from the fuel tank, and raise the pressure in proportion to throttle input, and send the higher pressure fuel to the injectors, where it is further pressurized for injection. If the pump is not working well, hard starting, low power and other issues can result.

In my case, the pump is equipped with an aneroid valve, which further adjusts fuel pressure based on turbocharger boost. If this valve is not working, the pump will never produce full pressure, and the engine will have low power.

I suspected my aneroid valve was bad, thanks to input from reb87 and others on this site. So I got busy and pulled the pump and sent it for rebuild. The task is simplified if you remove the fender, a simple 6 bolt task in my case (M915). To access the pump rear lower mounting bolt, I had to remove the power steering pump, a simple 2 bolt removal. The real trick to pulling the pump is the upper rear mounting bolt. This requires a 12 point, 7/16 swivel socket, such as a Proto 5274 (see pic). The rest of the task is very straightforward.

BTW, yes, the aneroid valve was bad, making my fire breathing Big Cam 400 perform like a wimpy 250. That problem is now behind me . . .

Rene M · 04-10-2010, 01:56

Quote:

Originally Posted by NDT

Here is some info for anyone faced with this task. First of all, the purpose of the Cummins PT pump is to draw diesel from the fuel tank, and raise the pressure in proportion to throttle input, and send the higher pressure fuel to the injectors, where it is further pressurized for injection. If the pump is not working well, hard starting, low power and other issues can result.

In my case, the pump is equipped with an aneroid valve, which further adjusts fuel pressure based on turbocharger boost. If this valve is not working, the pump will never produce full pressure, and the engine will have low power.

I suspected my aneroid valve was bad, thanks to input from reb87 and others on this site. So I got busy and pulled the pump and sent it for rebuild. The task is simplified if you remove the fender, a simple 6 bolt task in my case (M915). To access the pump rear lower mounting bolt, I had to remove the power steering pump, a simple 2 bolt removal. The real trick to pulling the pump is the upper rear mounting bolt. This requires a 12 point, 7/16 swivel socket, such as a Proto 5274 (see pic). The rest of the task is very straightforward.

BTW, yes, the aneroid valve was bad, making my fire breathing Big Cam 400 perform like a wimpy 250. That problem is now behind me . . .

OOOOOhhhhhh Big Cam 400...
how do you like it??? there is a b/c 350 in the corner of my shop i have been thinking of in-framing and tossing it to my m813..

Rene M · 04-10-2010, 02:01

Just a note : in your third picture .....
Most tech's just remove the 12 volt solenoid and fuel shut off from the pump " couple of screws and two square o rings" to get to that bolt. It will not change any fuel settings and make you life so much better when trying to get that darn bolt in or out. just seal the holes off with tape to make sure dirt does not get in the pump when your installing it.

vinny-socom1 · 04-10-2010, 08:45

Thanks for the info!!!

Vinny

Floridianson · 04-12-2010, 00:57

Did your tec raise the pressure?