You have an 03, there is a TSB for corroded connections on the ECU connectors that will cause all manner of issues. You might want to check into that before pulling all your hair out.

 

what does TSB stand for?

(I can not afford to pull out too much hair.....getting a little thin as it is)

 

Technical Service Bulletin, manufacturer will issue them to resolve known problems

 

It was just at the dealership for the diagnostic on this problem. Is it safe to assume they would have checked this?

 

what should RP be when you idle at 750 rpm? i hooked up my quad gauge MOMENTARILLY and it says 6000-7000 psi idling. reason i leave rp unplugged from quad rail gauge is if you leave it on too long you get a fried rp sensor. i burnt 3 rp sensors in 4 weeks. then i unhooked quad and now ive been going 7 months flawless.

 

When mine runs........rail pressure at idle is 4-5ooo psi. I use a quadzilla gauge.....is that what you mean by 'quad'?

 

yes. i use the quadzilla rail gauge. it shows me lift pump and rail pressure. is that what you use? have you blown rail sensors with it?

 

Don't take anything for granted unless you specifically tell them about the TSB's and verify they did it.

 

Mine is the quadzilla.......but it only shows rail pressure.

 

I checked the rail pressure relief valve today, by removing the fuel line from it, zip tying a bag to it, removing the fuel from the top of the valve then cranking it over to see if any more fuel appeared on the top of the valve. It did not......so I will assume that there is not a problem with the relief valve.

Just to have a look, I removed the relief valve from the rail, had a look, then reinstalled it. I connected a battery charger to one of the batteries as I had cranked it a few times trying to start it and to test the relief valve. I tried to start it once everything was back to normal and low and behold it started with 3 seconds of crank time. It started about five times in a row, each time requiring 3 secs crank time. I went back to see if it still started ten minutes later.........and it cranked but would not start showing about 1500psi on the rail pressure gauge.

It also did this same thing when I had the system open to test the injectors.

The only thing that changed was that the system was opened.......and the battery charger was applied. I can not remember the status of the battery charger before when this happened......I've had the charger on this truck so many times in the last couple months.

Please give the fact that it is more likely to start after the fuel system has been opened some thinking time........this is a concern for me that I can not understand

 

I paid attention to my RP at idle today........my gauge did read around 6k at idle. I have not blown any RP sensors.....but I have not operated the truck with it hooked up. I was going to connect it permanently........until I read your story...........?

 

Tried to drive the truck back to the dealership today to see if they could RE-diagnose the problem. Truck made it a mile down the road and quit. Would not start again. Had to have it towed to the dealership, who of course, was not happy to see me.

 

i have just joined this forum. i have been reading this tread. i have been having close problems as yourself. i have a 03 dually 4x4 stock. i lost power as yourself. when i first start up the truck, it runs fine till the temp warms up then i start loseing fuel pressure. i have replaced the lift pump. no help. then i put a light pressure gauge in between the lift pump and the cp3 so i could watch it. this light comes on after the truck warms up. i replaced the fuel rail becuase i was told that it was cheaper to replace all of it rather than just the pop of value( mine had popped) i thought that was my trouble....no luck. still doing the same thing. i put a fuel line from the lift pump to he fuel tack through the in inlet of the tank hope i was having some supply trouble.....no luck still the same. i did this sunday. i put it back to like normmally and left it. monday the air temp warmed up and it ran better going and comeing back from work. tuesday, it ran fine both ways and i ran it hard coming in.air temp was up to around 60. today temp dropped back down to around 35. went back to acting up again. this d**n thing is driving me nuts. i did replleace the fuel filter 3 times since this started back in Dec. no codes too. i am ready to trade it of. this is my 4 th cummins and this is the first trouble i have had. by the way the truck has 156000 miles om it too.

 

What pressure does the light come on at? Is it possible that you are losing the power supply for the pump from the ECM somehow and have no lift pump pressure at all. Did you replace lift pump with another stock one or did you replace with an aftermarket style?

 

5 psi. went back with stock. after the deal the last three days it is hard to say what the problem is. i think it is eletrical. if it was injectors, cp3.lift pump or somthing elese seems like it should do it all the time.