low fuel rail pressure

[joev4628]

Low fuel rail pressure on my 2008 kodiak 5500. Then the engine starts to shut down until I clear the dtc. This is a stock truck except we have eliminated the dpf and egr valve. How can I solve this prob with my V2 flashscan? Thanks Joe.

[loganlewis]

Did you change dpf to no and the value to 0? Did u turn egr codes off?

[AFTERMATH DIESEL]

Has anyone worked on the engine I have had two kodiaks one who had bad prv shimmed it and its been fine for over a year and the other someone had done warranty work(believe injectors) and when removing and installing damaged the rail and pressure would not hold under any load without throwing a code.

[loganlewis]

Just fealty with this. I had an lbz that had lower pressure after I shimmed it. Put a race valve in it and It was still low. Come to find out diesel swelled the o ring up when I originally took the fprv out and it had a nick in it. Try changing o rings and put a dab of grease on it and tighten it up.

[Meshanic]

Quick way to find out if it's caused by the prv is to stick some needle nose vise grips on the return line after the prv. Pinching it off there eliminates the need to disassemble anything but still shuts off your return flow. Quick and easy!

[Black6spdZ]

Quick way to find out if it's caused by the prv is to stick some needle nose vise grips on the return line after the prv. Pinching it off there eliminates the need to disassemble anything but still shuts off your return flow. Quick and easy!

on a rubber line?

[Meshanic]

It sounds kinda dumb but a good buddy of mine worked at GM for 10 years and now has his own shop and that's the way he's always checked it. It has worked for me you just have to be careful not not pinch the line too hard.

Really the best solution is always throw in a race fuel valve anyway. If you're gonna add any real fueling the prv's gonna get in the way. Just my 2 cents.

[Black6spdZ]

yea, I've heard of doing this on gas vehicles where you might see ~100psi max from the electric fuel pump but to cut off the return on a diesel?! Aren't the injector returns tied into the same line with the PRV? if the pressure built to high at best you would burst the rubber line, at worst could damage the injector o-rings and seals, etc.

[Meshanic]

As far as the pressure building too high for the injector o-rings, this has the same effect as installing the race fuel valve to eliminate the pressure relief. But as for the rubber line, now that is a different story. I never did this longer than a few minutes to log data and watch my fp. Long term definitely a bad idea. I'd never leave my driveway with vise grips attached to fuel lines. Doesn't sound very good anymore. I digress

[Meshanic]

Wait a minute. Working on another LBZ and that return line isn't rubber. It's that's really good, multi layered cotton covered hose I see all the time on heavy equipment hydraulic systems. That stuff's pretty tough. Unless you just pinch the carp out of it you won't hurt anything. I actually knew this but wudn't thinkin I guess.