2010 no rail pressure?

Gasoline Sucks

slow 12v
Joined
Sep 21, 2010
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967
2010 6.7 auto 4wd sat for 3 yrs after the front driveshaft exploded at 70mph. Took out the Transfercase trans and wiped all the fuel lines off the frame rail. We got the lines back together new trans and tcase installed. Now it cranks won’t start. 20psi lift pump pressure, fuel in the rail, commanded line pressure 5800 actual is around 19psi.

Loosened return line on fuel rail and fuel dribbles out of the banjo while cranking. It seems like a bit more comes out when the cp3 sensor is unplugged.

It had a maf code but it was unplugged we plugged it back in and the code is there but not sure we ever cleared it.

Wait to start light stays on and so does service 4wd. Motor is bone stock never tuned or deleted.

Bad fuel rail pressure relief? Bad cp3?

Appreciate any pointers.
 
Maybe since the fuel lines were ruptured for 3 years, the cp3 drained out and rusted/went bad....Return line on rail is for the relief valve, so you need to crack a high pressure line loose and see if it has pressure. The rail pressure sensor could be bad. Maybe debris from the old or new fuel lines you replaced got up to the cp3. So many possibilities.
 
Cycle the lift pump multiple times, there is no need to crack fuel lines.

Once you do that, data log to see what the rail pressure is when cranking.
 
Cycle the lift pump multiple times, there is no need to crack fuel lines.

Once you do that, data log to see what the rail pressure is when cranking.

No other codes.

Rail pressure is same as lift pump pressure as if cp3 is doing nothing. We have a new Bosch relief valve going to try it since there was fuel in the return line while cranking.

Any tips are appreciated
 
What is desired fuel pressure vs actual fuel pressure?
If it has been setting for 3 years, you could possibly have a plunger stuck in cp3
Could possibly be the FCA.

We can check on test stand to see what the flow numbers are on cp3.
 
Cranking desired was 5-6000psi actual was 17psi.

Unplug fpr on cp3 actual pressure was the same.

New bypass in the rail and a new rail pressure sensor still no start.

Whiff of brake clean and it fires. (I know don’t do that)….
 
I've had success freeing stuck plungers in rotary PLN setups by mixing carb cleaner and marvel mystery oil at about 50/50, pump it in (I use a clickity clack disposable fuel pump with a 32oz bottle connected), crank engine for a couple seconds with brew still pumping in, and let it sit over night.
So far I've never had this hillbilly method bite me. Perform at your own risk though!
Never tried this on any common rail pumps either....
 
I think your friend nailed it.....like several others did.





Just put a new one in mine after a blocked return line blew it up. Reman from II was I think $570.

That’s a deal couple quotes were over $1000. I got a low mile used pump from mark Nixon should be here next week.
 
That’s a deal couple quotes were over $1000. I got a low mile used pump from mark Nixon should be here next week.

I normally try to buy my stuff like that from Mumau Diesel but Trent is also a good friend and he was doing the work on Friday and said he could have the II here on Monday so I went with it.
 
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