CM2250 Poor fuel mileage

[Lonestar10]

Did you check the psv while doing leakdown test at 29k psi or regular idle?

[Truckdriven]

(03-05-2022 )Lonestar10 Wrote:  Did you check the psv while doing leakdown test at 29k psi or regular idle?

Checked it while doing leakdown test at 29k psi

[Rawze]

(03-04-2022 )Truckdriven Wrote:  ...
Also I ran Injector leak test and leakdown was 2090, 6k miles ago it was at 900, and 10k before it was at 340. I checked the rail relief valve and there was not a single drip. Something seems to be deteriating should I be concerned or wait till it gets worse and easier to find? fuel pump was rebuilt 17k ago.

The acceptable range is anything less than 4k psi on one minute (when doing the leak test at 30k psi) and its still ok.

[MCRENT]

Also I ran Injector leak test and leakdown was 2090, 6k miles ago it was at 900, and 10k before it was at 340. I checked the rail relief valve and there was not a single drip. Something seems to be deteriating should I be concerned or wait till it gets worse and easier to find? fuel pump was rebuilt 17k ago.
[/quote]

You might want to check the torque on the quill tubes. I had one that was leaking due to improper torgue. I was losing about 10K in a minute on the fuel rail leak down test and now she is sealed up and and holds above 29K for at least a couple minutes.

[Rockinbexpress]

Did you ever find a solution to your fuel milage problem? I have the same issue.