05 5.9 huge rail issues

1

12VALVEADAM

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Jun 27, 2011
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So this was all fine until I put the bigger injectors in. Stock cp3 and stock injectors had no problem. Now whenever the rpms go above 1600 the rail goes right to 26k and stays there until you go back below 1600. This is with udc and another one of the truck here is doing the exact same thing. And has is stumped. We have tried fca rail sensor pump and we are kinda lost at what to do next. Any help ASAP!! Thanks guys
 
Another thing if I switch back to stock tuning the rail is perfect? Would that mean it's in the tune with smarty? Anybody ever have this happen?
 
Try the PRV Might be weak and the CP3 is trying to maintain commanded pressure and it's dumped causing a spike. Since it's UDC You can pull up the tune and see where the rail pressure is set at.
 
The highest value I have for rail to be at is 13k wot. But it does not matter where I put it it won't ever stay in chexk
 
It the video you are displaying actual, what does it show for desired (commanded)?

Paul
 
Yes, I understand that, but what does the touch show for RPD (rail pressure desired)?
 
So I guess I can read that do I will update when I drive the truck this afternoon.

Also it seems to be fine for the first 10 or so minutes when I'm driving then it goes hay wire
 
Looking at the desired (RPD), will tell you if the computer is commanding the rail pressure to go that high. If it is commanding it to go to the 13K that you have programmed in UDC, and it going to 26K, then it is a control issued. If it is commanding it to go to 26K, then is probably something in the tune or sensor input side.

Paul
 
Ok I'll check that and for the llrp was 2 and hlrp 20 duration was 10 and 15 and timing was 10 35
 
12VALVEADAM said:
So I guess I can read that do I will update when I drive the truck this afternoon.

Also it seems to be fine for the first 10 or so minutes when I'm driving then it goes hay wire
Click to expand...

Sounds just like a bad FCA pigtail..
 
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