CM2350 fuel rail issue

[ktblogistics]

so have some codes for injector solenoid driver and turbo
for turbo inspected and replaced crankcase filter for maintenance free
(looked like clogged to full capacity)
replaced intake manifold pressure sensor
replaced exhaust back pressure sensor and check tube for clogging
both sensors were painted red so might be original with 750k miles

did fuel leak test and pressure dropped to 100psi within 16sec
so from 30k to 100 ,tried it few week before also
it drops like a extremly fast

did fuel amount test and had 100ml for 1min at 30k psi
used cummins tool at return line from block

what else i can do to find a solution or do i do something wrong
truck is demandated
thanks for your help

[Isv1]

I had this injector issue after a rebuild on another truck after I had sent them off to be tested. They supposedly rebuilt them in California and then sent back four out. The six kept throwing fault codes, so I did the injector performance test and replaced everyone that failed any part of those tests. it fixed my issue, but that was just my experience with it.

Also, I went {after-market} all six and so I replaced the ones that failed any test at all with the new ones and all my issues went away.

[Rawze]

(09-20-2023 )Isv1 Wrote:  ...
Also, I went {after-market} all six and so I replaced the ones that failed any test at all with the new ones and all my issues went away.

using after-garbage injectors is not a good idea, and is NOT recommended, .. here is why: http://rawze.com/forums/showthread.php?t...67#pid4367

You also should have done a proper leak test on them (mentioned in next post) instead of using the mostly useless injector performance test that Insite does. that test will will randomly fail brand new injectors, even on a brand new engine, as it has proven time and again to be absolutely unreliable.

[Rawze]

(09-20-2023 )ktblogistics Wrote:  so have some codes for injector solenoid driver and turbo
for turbo inspected and replaced crankcase filter for maintenance free
(looked like clogged to full capacity)
replaced intake manifold pressure sensor
replaced exhaust back pressure sensor and check tube for clogging
both sensors were painted red so might be original with 750k miles

did fuel leak test and pressure dropped to 100psi within 16sec
so from 30k to 100 ,tried it few week before also
it drops like a extremly fast

did fuel amount test and had 100ml for 1min at 30k psi
used cummins tool at return line from block

what else i can do to find a solution or do i do something wrong
truck is demandated
thanks for your help

FIRST.. if your truck is de-mandated, then you should have had a maintenence free crank case filter in it, or it should have been drilled out, etc..

Is that filter in the photo what it looked like, cut up like that when it cam out? ... or did you cut it up like that after realizing it was completely clogged?. - A dirty and clogged up crank case filter will cause turbocharger damage, bleeding turbo, etc... AND cause the the overhead cam(s) in the engine to flake out, because the cam(s) will get starved of oil.

==========

Your description of the injector test should be done exactly like this, I can only assume you did it like that video shows with the numbers you posted ...

http://rawze.com/forums/showthread.php?t...3#pid75483

... and if it fails then you need to fix whatever is wrong with the fuel system.

Maybe bad relief valve, maybe quell tube not seated or torqued properly, maybe bad and leaking injector, etc.

[ktblogistics]

the crankcase filter was like that,also there was slight film of oil on boost sensor when i replaced it
did fuel system leak test before and it mostly drops up to 5k within 1min , few times saw no drop at all, but it is the first time i see that it drops like that in the blink of an eye
also expected to have 300ml or more when i pressurize the rail to 30k psi an measure in jector fuel return amount,
checked the line if bended but not and have only 100ml in the cup after 1min

[ktblogistics]

have replaced pressure relieve valve , inspected the high pressure pump (rollers looked like new) ,no trim codes on injectors so might be aftermarket ones

so i run a fuel system test pressure goes up to around 15k when relieve valve opens up and pressure drops a little and goes up to 29k

no trim code on insite also
picture of injector is OEM

when you do a leak test and pressure goes up engine or pump starts to give you a little noise (assume works harder) at about 25k at this truck it starts to make noise at about 17k
any clues what i could test here
as stated before it drops from 29k to 150psi within less than 20sec

[SquareOne]

What are the miles on the pump currently? The high pressure fuel pump heads do go bad and aren't serviceable. There is a check valve inside the head that once compromised, requires replacement in order to correct.

I had this issue occur a couple years back on my 2350. I wasn't loosing nearly as much fuel pressure during the test, but I did have an external leak at the torx style plug on top of the head once the pressure test reached about 25k psi. Maybe there are other symptoms of the head failure someone else could elaborate on...

- Not sure if this pertains to you, but it is another direction to go after if everything else seems to check out. BTW, when performing the test with the compromised head, the engine would stumble once the psi started getting above 20k psi.


This is the thread about the issue I had...
https://rawze.com/forums/showthread.php?tid=7266

[tree98]

(09-22-2023 )ktblogistics Wrote:  it drops from 29k to 150psi within less than 20sec

A leak that substantial is likely a combination of problems and not just an injector or 2.

[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