low fuel rail press 559 code

[Shipit]

Isx cm2250 600,000 miles new pump installed before I bought the truck by warranty maybe 150 to 200 thousand miles ago. I operated it for a couple years now. Fault appeared heavy loaded on a hill I did fuel filters. Problem reoccured same hill. Next checked bleed down on rail it was less than 150 lbs in 30 seconds. During test pressure didn't go above 29,700 psi is that kinda low? I removed fuel pump head found excellent looking steel plungers , cam rollers great and was satisfied with appearance of pump.
!!!!! Except one plunger don't spring back during push test????. Quickserve says if this happens then a check valve in the pump head may be bad. OK then what? I guess Monday I will try to get some help at Cummins Cincinnati maybe they can sell me a new pump head. Any pump experts here??? Thank you very very much[/b]

[Rawze]

You inspected the pump,... good move to do that for the prevention of the dreaded pump failure of engine death.

The high pressure relief valve at the end of the fuel rail are notorious for being a second cause for what you describe. I would have replaced it to see if the code goes away before jumping to higher conclusions with the pump.

Also there is the pressure control regulator, partially blocked pick-up lines, or other things too.

Maybe also watch "commanded" pressure vs "measured" pressure and see how much differences there are.

[imalumberjack]

I think as far as cummins is concerned they will want you to by a new fuel pump at $4,000.00 bucks, try other checks first but I had the same issue where plunger would not return and it did not run right ...I pulled the barrels and replace the crush washers and it worked but I was doing all the things they tell you not to. 29,000 does not seem low ...if I remember right its from 9000 to 35,000?

[Shipit]

Thanks for the replies. One thing I also noticed is that the primary filter the one with the clear housing Pacar k34-1004. I noticed the fuel level is full. I thought that means it needs changed at that point? I changed it and it's still the same . I haven't seen any water and tank bottoms look clean. I'll dig back into quickserve and see if I can find more on low pressure side checks. As far as measured and command no big spread noticed but I need to have someone ride along and watch it pulling a load on the hills instead of static run. I'll look into that relief valve . Thank you again!

[jimeneztrans84]

Maybe the fuel pump actuator behind the fuel pump is going bad. Mine was bad and the pressure would jump up and down when looking at pressure on insite.

[Rounded_nut]

(09-23-2018 )jimeneztrans84 Wrote:  Maybe the fuel pump actuator behind the fuel pump is going bad. Mine was bad and the pressure would jump up and down when looking at pressure on insite.

How out of sync was it with commanded?

[jimeneztrans84]

It had a hard time reaching 29k pressure when doing pressure test on insite. It would jump up and down from 23k to 29k and drop really fast when doing the minute test. Idk if that's you're problem but start with the cheapest route. Change water separator filter, main fuel filter (could be clogged) actuator behind fuel pump.

[Unilevers]

there are check valves in the pump head, they do go bad and cause 559 codes. If the plunger doesnt come back when pushing on it one of the check valves may be gone.

Uni