CM2250 Fuel pressure sudden drop

[DTidwell05]

Okay, I am tied of throwing money at this thing!

Here is what the truck is doing....
Starts up just fine and sounds good, once it reaches 160 degrees coolant temp the fuel pressure just drops suddenly and the engine dies. It gives a code for low fuel rail pressure and that's it.

We have replaced the high pressure fuel pump and the low pressure supply pump also. before replacing those, the truck would die around 140 degrees so it might have made a small difference.

I am leaning towards bad injectors, but I am just stumped why the pressure holds good until a certain engine temp and then just drops out quickly. Also eliminated the regulator being bad.

Any ideas?

Thanks!

[Rawze]

(06-25-2024 )DTidwell05 Wrote:  Okay, I am tied of throwing money at this thing!

Here is what the truck is doing....
Starts up just fine and sounds good, once it reaches 160 degrees coolant temp the fuel pressure just drops suddenly and the engine dies. It gives a code for low fuel rail pressure and that's it.

We have replaced the high pressure fuel pump and the low pressure supply pump also. before replacing those, the truck would die around 140 degrees so it might have made a small difference.

I am leaning towards bad injectors, but I am just stumped why the pressure holds good until a certain engine temp and then just drops out quickly. Also eliminated the regulator being bad.

Any ideas?

Thanks!

No matter what the reason for the engine shutting off,.. the fuel pressure "Measured" should not drop off to nothing instantly like that. It should hold whatever pressure it was being commanded at for several minutes after. Just make sure your not loosing communications to the ecm.

Try to do a rail leak test like this video shows.. at 30,000 psi. See what the leak rate is.
ref: http://rawze.com/forums/showthread.php?t...3#pid75483

If it will not run long enough for the leak test then start by replacing the high pressure relief valve.. and of that does not fix it .. then use an injector cap-off kit to cap off up to 3 injectors at a time and try that way.