Injection pump leak test cm2250

[Rockinbexpress]

Hey all, I'm locked out of quickserve for the moment (forgot password). What is the procedure to isolate and confirm a high pressure fuel leak at the pump. I ordered more fittings to block all the injectors. Is that all I need to do? Crank and watch for pressure drop? Thanks

[SquareOne]

(04-19-2023 )Rockinbexpress Wrote:  ...What is the procedure to isolate and confirm a high pressure fuel leak at the pump. I ordered more fittings to block all the injectors. Is that all I need to do? Crank and watch for pressure drop? Thanks

I believe this is an example of what you're looking for...

https://rawze.com/forums/showthread.php?...2#pid69262

- This test would let you know if the high pressure fuel system is in fact leaking. It will also give you an idea of the severity of the leak (depending on psi drop in the allotted time) if there happens to be one. This is the best way to begin high pressure fuel system diagnosing then you can take proper steps to isolate the leak.

[Rockinbexpress]

Thanks squareone I've done that test. I guess if you eliminate the injectors the only thing left is the pump itself. The pump is under warranty but I have to buy a new one and wait for a refund so I want to make certain it's the pump before I spend another $4k

[tree98]

Could also be relief valve on the end of the fuel rail.

[Rockinbexpress]

(04-20-2023 )tree98 Wrote:  Could also be relief valve on the end of the fuel rail.

Tree98 I checked the relief valve it's not leaking.

[Rawze]

(04-20-2023 )Rockinbexpress Wrote:  Thanks squareone I've done that test. I guess if you eliminate the injectors the only thing left is the pump itself. The pump is under warranty but I have to buy a new one and wait for a refund so I want to make certain it's the pump before I spend another $4k

before assuming it is bad injectors.. be sure to re-torque all the injector supply tubes going into the head first, and do the check a second time. Sometimes it is only the injector supply tubes that get leaky.

[SquareOne]

After the re-torque of the tubes if you're still having issues, check the fuel pump head. Could possibly be compromised. Does it stumble when building pressure during the test? It would be about half the cost of the pump (if they're obtainable currently).

http://rawze.com/forums/showthread.php?tid=7266

^---- Check out that thread for an example of what I'm talking about.

[Rockinbexpress]

Squareone that's the right direction. So there isn't away to isolate and pressure test just the pump? Like say cap off all 6 injectors and crank the engine to build pressure then check for leak down?

[SquareOne]

(04-22-2023 )Rockinbexpress Wrote:  Squareone that's the right direction. So there isn't away to isolate and pressure test just the pump? Like say cap off all 6 injectors and crank the engine to build pressure then check for leak down?

Not that I'm aware of, but others on here may know something else. Cummins didn't have a procedure that I was aware of when hunting awhile back.

**Here are a few questions that would help give an idea on the pump health...What is the highest pressure you've seen while doing the test? Whats the numeric pressure drop after a minute? Also, what the hours/mileage on the pump? Has anyone pulled the head and inspected the internals? Has the fuel mileage been suffering? What made you do the pressure test in the first place, was it just a preventive maintenance step or is something abnormal going on (i.e. an engine light, power loss, black smoke, low mpg, etc.)

Basically, is this a smaller pressure drop, say up to a couple thousand psi in that minute, or something much more?