2250 Low Fuel Rail Pressure

[Knuckles]

One of my deman CM2250 occasionally gets low fuel rail pressure code, It wasn't staying primed so i checked for leaks on suction side and installed a new lift pump, ran a high fuel pressure test and as soon as the engine comes to a stop the pressure Immediately goes from 29,000 to 0psi or even -20psi, I changed the check valve, no luck, I isolated each injector with a fuel rail plug and no luck either, I didn't want to buy 5 plugs like quick serve says because they're $108 a piece here, so its possible that more than one injector is leaking but when i do a cylinder cut out test, each cylinder sounds the same. I have removed the pump head it has a two barrel steel plunger, I tested it like quick serve says it looks good, so at this point I'm not sure as to where to look for pressure loss, the oem filter doesn't ever fill to view like it used to so I'm thinking its still getting air suction but I'm not sure how that interferes with the fuel rail pressure drop, any suggestions would be much appreciated, thanks in advance!

[Unilevers]

(08-03-2019 )Knuckles Wrote:  One of my deman CM2250 occasionally gets low fuel rail pressure code, It wasn't staying primed so i checked for leaks on suction side and installed a new lift pump, ran a high fuel pressure test and as soon as the engine comes to a stop the pressure Immediately goes from 29,000 to 0psi or even -20psi, I changed the check valve, no luck, I isolated each injector with a fuel rail plug and no luck either, I didn't want to buy 5 plugs like quick serve says because they're $108 a piece here, so its possible that more than one injector is leaking but when i do a cylinder cut out test, each cylinder sounds the same. I have removed the pump head it has a two barrel steel plunger, I tested it like quick serve says it looks good, so at this point I'm not sure as to where to look for pressure loss, the oem filter doesn't ever fill to view like it used to so I'm thinking its still getting air suction but I'm not sure how that interferes with the fuel rail pressure drop, any suggestions would be much appreciated, thanks in advance!

your wasting your time unless you have 5. you wont find it as I guarantee in your situation its more than one. Did you check the barrel and plunger orings and sealing washers? the check valves in the pump head?

doing a cutout test will tell you nothing in a high pressure leakage situation.

[Knuckles]

(your wasting your time unless you have 5. you wont find it as I guarantee in your situation its more than one. Did you check the barrel and plunger orings and sealing washers? the check valves in the pump head?)


Ok I guess Ill have to go buy the rest as well then. I did test them by applying air to see if the plungers extended and by pushing back down on the plungers and they pop back out like they should, do i need to remove the barrel retainers to check the orings and washers? I read on quick serve i have to replace the barrel retainers if I removed them.

[tree98]

Knuckles, did you see this thread?

http://rawze.com/forums/showthread.php?tid=356

[snailexpress]

You can use fuel rail to injector connection line instead of test plugs. Ask Cummins for cheaper one as and cut pipe in two half. Heat the cut end with torch and flatter it. Then weld.
   

[Rawze]

before you go crazy, re-torque all the feed tubes that go into the head and do the test once again.

[Lonestar10]

while that test peice you have snail is nice and cheaper if someone isnt a decent welder it could be deadly if they are crazy enough to get near the engine running with them on.

[OTR48]

(08-03-2019 )Knuckles Wrote:  One of my deman CM2250 occasionally gets low fuel rail pressure code, It wasn't staying primed so i checked for leaks on suction side and installed a new lift pump, ran a high fuel pressure test and as soon as the engine comes to a stop the pressure Immediately goes from 29,000 to 0psi or even -20psi, I changed the check valve, no luck, I isolated each injector with a fuel rail plug and no luck either, I didn't want to buy 5 plugs like quick serve says because they're $108 a piece here, so its possible that more than one injector is leaking but when i do a cylinder cut out test, each cylinder sounds the same. I have removed the pump head it has a two barrel steel plunger, I tested it like quick serve says it looks good, so at this point I'm not sure as to where to look for pressure loss, the oem filter doesn't ever fill to view like it used to so I'm thinking its still getting air suction but I'm not sure how that interferes with the fuel rail pressure drop, any suggestions would be much appreciated, thanks in advance!

Can you please post the Fault code you get?

[Rawze]

(08-03-2019 )Knuckles Wrote:  ...
pressure Immediately goes from 29,000 to 0psi or even -20psi,
...

If it is leaking as bad as you say, it should be easy to find with this method ...
http://rawze.com/forums/showthread.php?t...56#pid2556