ISX "whistling" and shut down

[CoroView Shop]

(05-08-2024 )JimT Wrote:  Ok, first off that 3-cylinder pump was an engine failure waiting to happen with only a low chance of being the source of your issue. Good that it's replaced, but also not surprising that the issue remains.

I'm going to do some guessing here based on what you wrote across multiple posts. Hopefully something I ramble off will help :)

First off, to reword your description: Truck starts and runs fine at idle. Once under a load and a higher rate of fuel supply is needed a whistling sound appears followed by the secondary fuel filter running dry, or at least dry enough to interrupt the supply of fuel to the gear pump. I'm making the assumption that the fuel filter is running dry because you stated that cycling the key a few times will reprime the system and the process repeats. Other then the anomaly immediately following replacement of the pressure relief valve, it sounds like you have some kind of leak, probably between the Davco (or whatever water separator you have) and leading into the high pressure pump.

Do you have a Davco unit or some other water separator that you can visually see the fuel level and if there's any air bubbles? When the engine shuts down can you verify that there's enough fuel flowing from the water separator to the secondary filter?

My thoughts: either your sucking air in prior to, or at, the water separator OR you're sucking air in at or around the secondary filter. Possibly from the filter housing itself. You said the truck went into a ditch, the force could have damaged the filter housing where the filter spins on? Maybe a very small crack? Dunno, just speculating.

There's tons of diagnostic and troubleshooting info available on cummins quickserve, including detailed diagnostics for the fuel system.

You never gave any details about the truck make, model, year or the actual engine. I'm assuming from the existence of a 3-cylinder pump that this is an early cm2250, possibly 2010 or 2011? If so then the following link to cummins quickserve should apply:

ISX cm2250 service manual 40222250 - section 005-236 fuel system diagnostics

Also, it should go without saying, but you probably want to go back and double triple check all those new hoses and connections from the tanks all the way to the filters. You have a small leak, somewhere. Maybe disconnect the fuel supply hose from the tank and the water separator and pressure test the hoses?

Given the association of a whistling sound and the subsequent engine shutdown I wouldn't think the ECM should be considered at this point.

Hi there,
Just an update as to what we're finding so far. The primary filter never runs dry, and we did suspect the secondary might be getting sucked dry, however finding that isn't the case. (After it stalls, we shut off the key immediately and removed the filter.)
I've monitored live data and found that it leaks down to almost 0 psi in about 10-12 seconds, which I believe is excessive according to Quickserve. At idle, commanded pressure is 8700 psi, and I can watch actual pressure drop off quickly after about a minute of run time. I initially thought that it was sucking the secondary filter dry, but that doesn't appear to be the case. Why, then, would it drop high side pressure and quit after about a minute or so? I'm back to thinking that perhaps the 3 cylinder pump was still pushing some dirt around and caused the relief valve to fail, but don't have the test equipment to verify. According to Quickserve, 10 drops over 60 seconds is a fail. The other possibility is a failed injector, but wouldn't that cause a hard start/black smoke condition?
I am far more familiar with the DD platforms, so any help is very much appreciated!
T