CM2250, fuel leak mystery, please help!!

[Starlight]

I did a full set of onjectors at the end of last year and installed new fuel connector tubes with them. A week later customer said he had a fuel leak at number 2 so i go to check it out at his place thinking the o ring on the tube was cut when installing it. It was fine so i closer look at the supply tube from the rail and i saw fretting right on the beveled tip where it seals to the connector. Replaced the connector and supply tube fixed it. The torque on the originals was low and didnt seal properly on a new connector causing the leak. Might be your issue too. Signature620 mentioned that as well.

[JMBT]

Starlight: thanks for the reply. Yes I am hoping that is the case. Each of my 6 rail to Fuel connector tubes had a bit of corrosion on their tips. Nothing you could even feel with your fingernail. I cleaned it off with a brass brush and electrical contact cleaner. The weird thing is only #5 is leaking and they all looked the same.
I’ll post back on Monday when I put the new parts on.

[snailexpress]

(01-27-2018 )JMBT Wrote:  Snail: have you checked the ECM cooling plate, behind the ECM? Maybe?

Signature620: I have ordered both those parts even though the old ones looks fine. I will be replacing them Monday. I hope that gets it.

Still can’t figure how it could be leaking there yet performing so well?? Also only losing 200-300 psi on leakdown test??

Yes I did it first because it was wet ECM. Everything is dry behind ECM only fuel in wire loom and plugs. Fuel lines over ECM all was dry. Fuel lift pump is dry. Mystery.

[JMBT]

   So here are the parts I just got from Cummins. $172 worth. From left to right, $70, $12, $70. Plus freight & tax. Of course in true Cummins fashion they all need primer and paint, so I am outside at the truckstop painting them on some cardboard in the dirt. I will install them tomorrow, hopefully the end of leaky number 5.

[jimeneztrans84]

Did these new parts fix the diesel leak?

[JMBT]

Yes, it did. Actually I think the only "bad" part was the fuel tube that runs from the rail to the injector supply tube. (far left in the pic) the original had a tiny, and I mean tiny bit of corrosion on the sealing surface of the tip that butts up against the injector supply tube. You couldn't even feel it with your fingernail, but I tried to clean it off with a brass brush and apparently that wasn't good enough.

[jimeneztrans84]

(01-31-2018 )JMBT Wrote:  Yes, it did. Actually I think the only "bad" part was the fuel tube that runs from the rail to the injector supply tube. (far left in the pic) the original had a tiny, and I mean tiny bit of corrosion on the sealing surface of the tip that butts up against the injector supply tube. You couldn't even feel it with your fingernail, but I tried to clean it off with a brass brush and apparently that wasn't good enough.

Good to hear jmbt just sucks had to gamble on all the parts...

[Rawze]

(01-31-2018 )jimeneztrans84 Wrote:  Good to hear jmbt just sucks had to gamble on all the parts...

30+ thousand PSI of any gas or liquid is difficult to contain. I have seen metal hydraulic lines at those pressures sweat the gas or liquid right through them before simply due to impurities in the steel when they were formed.

[JMBT]

Yet another reason to stay with an 871 or older, huh!!