Help!!!! Low Rail Pressure!!

[TCDiesel]

the Tubes are fuzzy every time you remove/install the dip may get deformed, with all the vibrations the tubes will leak and lose Pressure,once this happens the drop pressure in some cases is detected and found to out of value the system/Ecm will adjust/drop the pressure to try and stop the system from major leak. . All things consider equally are subject to change, the nature of CR.

 

[dan shss]

My Rail pressure at idle is 5k ,,,,I think its the cp3

 

[TCDiesel]

What was the Spike PSI when you turn off the engine, should hit 12/14k

 

[dan shss]

What was the Spike PSI when you turn off the engine, should hit 12/14k

I forgot to look at the spike but it did go way up when the key was turned off.

 

[dan shss]

Im getting a Remain Cp3 from Dodge Dealer Thursday So I will post back and see if this fixed my problem... .

 

[JDerbedrossian]

From idle at 4500 to 5200psi shut down engine report what the max spike was,do this 3 to 5 times for correct readings,if no spike bad injectors,if extreme spike clogged tubes, or both. 6k is a little high at idle.

My gauge has never spiked, but its running properly. Now you got me thinking.

 

[dan shss]

Changed out my cp3 and my truck runs great!!!



These CR,s can be tricky to diagnose

 

[JDerbedrossian]

Changed out my cp3 and my truck runs great!!!



These CR,s can be tricky to diagnose

Does your rail gauge spike when you shut off the truck with the new cp3.

 

[Scrappy]

I'm glad you figured it out!

How is your rail pressure @ WOT now? and what levels are you running on the boxes? I need a starting point since I don't have a RP gauge. I just got the truck buttoned up this evening!

 

[dan shss]

I unhocked my RP gauge I just had it wired in temperally for a diagnosis tool. .

I will wire the RP gauge back in soon.

 

[Scrappy]

What was the Spike PSI when you turn off the engine, should hit 12/14k

is this with the truck stock? I am seeing ~25000 on shutdown with the Mp-8!

 

[TCDiesel]

is this with the truck stock? I am seeing ~25000 on shutdown with the Mp-8!

If it is correct, that spike is in the extreme zone

 

[Scrappy]

do the modded pumps spike higher? I turned the Mp-8 down and still spiked as high. My FCA is modded.

 

[TCDiesel]

I have never seen anything over 15k, Maybe your gage is faulty.

 

[Floor It]

The most common spike at shut down is 17 to 18,000 psi 03' to 07'.



John

 

[TCDiesel]

The most common spike at shut down is 17 to 18,000 psi 03' to 07'.



John

Thanks for the update...

 

[JDerbedrossian]

The most common spike at shut down is 17 to 18,000 psi 03' to 07'.



John

Since day one of the install my gauge has never spiked and the truck runs perfect, I have 65,000 miles 30,000 of it with the gauge. Do I have an issue?

 

[Scrappy]

john, what are the modded pumps doing on shutdown?

correct me if I am wrong but the FCA defaults to the full fuel position when disconnected right? doesn't it also lose power on shutdown(defaults to full fuel) and the pumps are still turning causing the spike? By this thinking, the modded pumps should have a higher spike because they can flow more fuel?

 

[LWorthington]

I am having the same problem on my 03. The truck runs hard untill it hits 15k fuel pressure, then it falls on its face. If I drive it and play with the throttle keeping it below 15k it will accelarate as soon as I fuel over that it sucks. The tuck will also do this if I break stand it. I have tried stock, smarty. tst, and bully dog it does it with all of them. Truck has new CP3 (stage 2 industrial injection) new stock injectors and new fuel tubes. It idles at 5k, When you turn the motor off it spikes to 14k.



I have also replaced every sensor under the hood and the tps. Anyone have any ideas???

 

[Strokercummins]

Hi



Could some of you CR experts give me a hand or better yet, your knowledge? The CR pressure relief valve has a history of failure. I have been looking on the web for a few days to find out why.

This is what I've heard. (1) The spring weakens and looses its force (2) The seat and poppet become etched (3) The poppet tip breaks off

What have you guys experienced? Have you done any testing on the CR relief valve?



Thanks for helping me out.

Rob