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Tberg · 07-11-2023, **(Subject: Fuel Problem Cummins )**

have you checked fuel pressure with a gauge? talking gear pump pressure? I had a weird 1 that the drive for the gear pump was slipping on its own shaft. Essentially it would run off of the lift pump feeding the high pressure pump until the lift pump would turn off at 30 seconds and than unit would die. Was hard starting also.

Rawze · 07-12-2023, **(Subject: Fuel Problem Cummins )**

Has anyone bothered to monitor the fuel pressure while cranking?.. and then at idle?. Has anyone verified the fuel pressure is not falling off or is weak?.

Therealarw · 07-16-2023, **(Subject: Fuel Problem Cummins )**

(07-12-2023 )Rawze Wrote: Has anyone bothered to monitor the fuel pressure while cranking?.. and then at idle?. Has anyone verified the fuel pressure is not falling off or is weak?.

Rawze,

Hey man I did check the rail pressure. Used Insite, ended up pulling all the injectors out. 3 were staying stuck open and 3 were not opening all the way. It was hard starting but I put injectors in it, and it ended up starting up, but for some odd reason I can’t get the fuel bowl to stay full… I’m going to check it out Monday. I’m not sure if I can send photos I’ll post them in here. Might be able to help you guys out so you guys can have a better reference of what I’m talking about, but truck runs, only running off 5 injectors but I’m going to see what’s going on. Don’t have any power to the #1 injector. Not sure if the fuel bowl staying empty has anything to do with the injector but it’s been a pain trying to figure out exactly is the problem.

Therealarw · 07-16-2023, **(Subject: Fuel Problem Cummins )**

(07-11-2023 )Tberg Wrote: have you checked fuel pressure with a gauge? talking gear pump pressure? I had a weird 1 that the drive for the gear pump was slipping on its own shaft. Essentially it would run off of the lift pump feeding the high pressure pump until the lift pump would turn off at 30 seconds and than unit would die. Was hard starting also.

I put a brand new fuel pump on it actually man.. Old one actually had a bad camshaft in it so it wasn’t supplying enough pressure to the rail. Put a new pump in it. Then the injectors were giving me a hard time. I actually had them all rebuilt, just put them back in and everything looks good, just wondering why the fuel filter on the outside of the frame won’t stay full. It’s been super annoying.

Tberg · 07-17-2023, **(Subject: Fuel Problem Cummins )**

I am confused. How did you know 3 injectors were stuck open? How did you know 3 were not opening all the way? How do you know its only running off of 5 injectors? Also, depending on the type of fuel/water separator a full fuel bowl indicates the filter is due for a change.

Therealarw · 07-17-2023, **(Subject: Fuel Problem Cummins )**

(07-17-2023 )Tberg Wrote: I am confused. How did you know 3 injectors were stuck open? How did you know 3 were not opening all the way? How do you know its only running off of 5 injectors? Also, depending on the type of fuel/water separator a full fuel bowl indicates the filter is due for a change.

I took the injectors out and had them tested and rebuilt. That’s what the people had told me. And I have Cummins Insite so I had plugged into it and did a cylinder cutout test and found out I wasn’t getting any power to #1 injector

Rawze · 07-17-2023, **(Subject: Fuel Problem Cummins )**

(07-17-2023 )Therealarw Wrote:
(07-17-2023 )Tberg Wrote: I am confused. How did you know 3 injectors were stuck open? How did you know 3 were not opening all the way? How do you know its only running off of 5 injectors? Also, depending on the type of fuel/water separator a full fuel bowl indicates the filter is due for a change.

I took the injectors out and had them tested and rebuilt. That’s what the people had told me. And I have Cummins Insite so I had plugged into it and did a cylinder cutout test and found out I wasn’t getting any power to #1 injector

sounds like the typical load of crap those injector rebuild shop tell people.

there are proper ways to check the injectors WITHOUT EVEN TAKING THEM OUT OF THE ENGINE!!!.. FOLLOW PROPER PROCEDURES AND STOP GUESSING LIKE A DAMN FOOL
!!!.

for the CM870, 871, CM570's...
ref: http://rawze.com/forums/showthread.php?t...8#pid67948
for the common rail engines ...
ref: http://rawze.com/forums/showthread.php?t...3#pid75483

And by the way.. here is my input on injector rebuild shops...
ref: http://rawze.com/forums/showthread.php?t...67#pid4367

Therealarw · 07-26-2023, **(Subject: Fuel Problem Cummins )**

Hello, Yeah I can see how rebuild shop can be a load of crap.. I'm at complete loss I am having by far the hardest time trying to figure it out, the truck just loses rail pressure at about 10-15 mins of idling.. No codes flashing, I noticed watching rail pressure it would just drop down to 3000 psi then 1500 and then shuts off then it's hard to get it to start, takes 3 key cycles to get it to run again... I'm going to end up needing more tooling to do these tests