[Mad cummins owner]

I have an 06 ram 5.9 cummins 24v. A week ago I noticed my truck was cranking longer each time I started it throughout the day and 2 times that day on a hill it seemed to not want to accelerate past a certain point then cleared up. Next day same thing in the morning and after work. Following day it cranked for about 10 seconds and didn't start, thought it was the cold so I tried again and another 10 seconds or so before it started. Same again today on a much warmer day. I just replaced the injector pump, pick up pump and filter back in October. I've had a code for intake grid heater since I bought it and I've replaced it but the code has been there for 2 years and I've never had this issue. When I scanned it the other day I had a few codes for fuel delivery and turbocharger over boost. Today it took a few attempts of long cranking before it finally started and there was no codes. Fuel pressure at idle bounces between 6,400 and 7,300 psi. Anyone have any ideas on what to check next? Trucks been down for a week now.

 

[twildman]

How old are the batteries, have you charged them lately?

 

[rghavana]

What is rail pressure when long crank?
plug in block heater if it starts easier usually injector worn.

 

[Mad cummins owner]

Batteries are good only a year and a half on them. Didn't have time to check cranking psi til today and it figures the truck fired up no problem and it even went into high idle as normal which it hasn't done since the problem started.

 

[Mad cummins owner]

Batteries are good only a year and a half on them. I'll have to check the psi on crank after work. Once it finally starts I can shut it off and start it right back up but if it sits for about 20 minutes or so it Cranks long. Just checked it yesterday and it started right up. Key on fuel psi is 49 and once I crank it it jumps to 1,300 and climbed quick. Not sure what caused the issue also not sure yet if it's actually gone.

 

[GRUNT 11B]

Possibly worn injectors. Any smoke when it starts up? You can retorque the feed tubes and run a heavy dose of cleaner and lubricant. That might help.

 

[Mad cummins owner]

Yea it smokes everytime but I also have blowby. Didn't know how to check for it before I bought it kind of started thinking maybe an injector.

 

[GRUNT 11B]

Injectors and/or low compression are possibilities. I'd try what I suggest as well as finding out the info rghavana asked about.

 

[rghavana]

Fuel in oil?
With those strange RP readings and blow by
I would do like GRUNT 11B stated check connector tube torque, at same time check for injector issue by using a fuel line cap to block off injectors one at time.

 

[Mad cummins owner]

Thought I found a small fuel leak yesterday at one of the lines to the injectors so I checked torque on injector tubes and checked tightness on all lines also changed fuel filter for the hell of it. Had it running hoping it was fixed but this morning same thing with the long cranking. Even does it after sitting an hour while engine is still warm which makes me think I'm losing prime in the fuel system somewhere.

 

[rghavana]

Yep , and most common cause is injectors

 

[Mad cummins owner]

So at idle what does everyone think the fuel psi should read on the scanner? Mine usually read 7,000 and 7,200 but now as as it warms up it fluctuates between 6,200 and 6,800 but runs smooth for the most part. Also after it cranked for awhile( 3 attempts at 15 seconds each) I got a code for the crank sensor but the rpms read normal so I believe it's just from cranking for extended periods. Can't afford 6 new injectors right now so I'm really hoping that's not the problem if so the truck will down for awhile

 

[5.7 Hemi]

Get a crankshaft sensor, cheaper than 6 new injectors.

 

[cattlepuncher]

Over the course of the past year, I’ve installed a 10mm CP3, T&C diesel modded rail pressure relief valve, 6 nearly new injectors with new connector tubes, lines, and rail. so far I’ve found a couple theories:

1.) Rail pressure has gotten more and more stable with replacement of each “leakable” component. First started with rail pressure release valve. Less fluctuation at idle and at cruise. Crank to fire maybe slightly shorter.

2.) Last time connector tubes were torqued was 5 years ago. They were all loose, significantly. I can’t remember the revised Cummins torque off the top of my head but it’s around 41 ft-lbs. I used torque wrench to loosen and all broke free somewhere between 15-30 ft-lbs. Maybe you get lucky and that’s enough to completely seal the tube, but probably not. That is a significant issue for getting rail psi to pressure required for ECM to fire injectors. Not to mention guys trying to make as much power as possible out of their CP3 supply.

3.) Lastly, injector return flow. You could have prom night tight rail pressure relief valve and connector tubes, but if the control valve in 1 or more injectors is leaking heavily, you’ll have all sorts of issues. Obviously this is $2000+ vs a $100 PRV (highly recommend T&C diesel out of Minnesota, they can rebuild to better than OEM spec, for cheaper than OEM new). Recommend replacing PRV first (most OEM valves on these old of trucks are leaking, just depends how much) and retorqueing the connector tubes. Make sure to use a 24mm crows foot on tube hold down nut while tightening 19mm injector line to make sure tube doesn’t lose torque. If those two things don’t work, then start looking at $2000+ injectors.