cranks hard start

[rkrausff29]

hi i have a 06 cr cummins i have 14 psi on the lift pump at the injection pump its hard to start and when i turn the key off i can watch the psi drop to 3 psi if i give it a hit of starting fluid it starts rite up. is there a banjo bolt with a fuel pressue spring on the return any were like there was on my old 12 valve thank u

 

[AH64ID]

That is generally a symptom of failing injectors.

How many miles on it?

 

[rkrausff29]

120,000 is there a pressure return valve on it my old dodge would get that way i would have to change it

 

[AH64ID]

HPCR's are different than 12V's in lots of ways.

 

[cerberusiam]

The fuel return is orificed thru the injectors and CP-3. If those are high for whatever reason you have a slow\no start.

 

[rkrausff29]

i know when i typed in my year on another site for injector parts a prv came up thats why i was asking

 

[AH64ID]

i know when i typed in my year on another site for injector parts a prv came up thats why i was asking

That is the high pressure relief valve and while it can fail it generally doesn't do what you are describing.

 

[rkrausff29]

ok thanks i guess cap each injector line and look to see were the leak down is

 

[cerberusiam]

The PRV can definitely cause slow\no starts if it is blown. Not a usual occurrence but it can do it. One of the things that needs tested in the process.

 

[AH64ID]

The PRV can definitely cause slow\no starts if it is blown. Not a usual occurrence but it can do it. One of the things that needs tested in the process.

There should be some low pressure CEL's with a compleatly blown one thou since the CP3 won't be able to keep up with most demands. It is worth testing thou.

 

[rkrausff29]

were is the prv on this truck

 

[sag2]

It is on the fuel rail toward the front of the engine. It has a banjo bolt on it with a return line going back to the filter housing.

 

[AH64ID]

The PRV is serviced as a unit with the rail from Cummins/Mopar, and IIRC the OEM unit is set somewhere around 26-28K psi. Todd at TC Diesel may be a good person to call.

IIRC you test it by removing the return line and cranking. If fuel comes out it is bad but if no fuel comes out while cranking that isn't your issue.

A few WOT runs thru 3,000 rpms may also set a code if it is opening prematurely and the CP3 cannot keep up.