CM2350 fuel rail issue

[Colter]

2350 injectors wont always show trims in insite as they can be reset. You can put in the trim code and it will take accept them but wont show the trim code, easier to just reset them as needed.

Your injector leakage quantity is in spec so for now ignore the injectors, they are not the issue until the rest of the steps are taken

Get your self a quickserve account so you can follow the procedure referenced in the insite trouble shooting, you have the main tool already if measuring return quantity. Repeat the same fuel leakage test but with your fitting and line in the fuel pump return line (the second port on return manifold, injector return is the third) after pressure is stabilized at your 29k measure pump return for 30 seconds, you should be 300-525ml, if its above there's a failed check valve in the pump head, below rarely happens so I can't fully remember but I think actuator housing issue, quickserve will confirm.

If testing your rail relief put your tool in the fourth port, run test, 10 drips a minute is the leakage limit. If you replace the relief you absolutely must replace the sealing washer. That washer can be BIBLICALLY difficult to get out and can cause the loss of will to live.

If the fuel pump head is off, manually check your plungers and make you have to get physical with them to push them in, if one is loose that's the side with the check valve failed.

fuel pump actuator, check o-ring for rips/tears, check housing as occasionally actuator wears into housing and even a new one will leak.

If you remove the actuator housing there a tiny little screen molded into it that can plug up and cause issues. There's a TSB on it but not easy to find it (also in Quickserve)

In some rare cases fuel connector torque issues will cause hidden problems, injector return quantity will be okay but 559 will still be an issue, only ever had that issue once so that is very very last.


Also never go with aftermarket injectors unless you feel like doing things twice, it suck to spend big money but its better then doing it again. Take the time to find the actual issue and problem will be solved.

From the point of view of a mechanic; a lot of drivers/companies/owner-ops ask for unnecessary amounts of things to be done (I believe out of frustration at incompetent mechanics, loss of time/revenue, and shop talk of "well it was this last time" or "it was this on my truck so change that") and shops will just do it and bill for it. On the flip side shops without proper experience and tooling just pulling out the parts cannon without any consideration to the cost especially in regards to a one truck show. A couple hours of proper diagnostics is much cheaper then 1 injector let alone 6. This forum is excellent for information as well as a ton of information and experience not written in any manual.

The good news is you have a very common issue and usually an easy find, this battle is how we learn and the next one will be a relative breeze