High pressure relieve valve

[TCluff]

somthing you may want to consider is the symtoms of a bad cp3 are the same as a bad valve! you may want to check the return flow on the cp3 before you buy another valve :-laf

could the fca be faulty and letting too much fuel in causing a press spike thus destroying the valve?

 

[EB]

I had the truck in the shop last Monday because of the hard cranking issue. They checked the lift pump, it was OK, they checked the CP3, it was putting up the required pressure, and they checked the valve, it wasn't leaking. Four days it was leaking so much the truck wouldn't start. Don't know what else to check or do.

 

[RMalone]

If the cp3 is makeing pressure then I don't see how the relief valve could be causing the no start. What about cam and/or crank sensors? I would think they would throw codes but ya never know.

 

[Mark1si]

If the valve isnt holding pressure in the rail it wont start.

 

[BRayls]

He is on his Third,almost all of the issues associate with this valve is spike Pressure, NOT constant, your thought on quality control on three valves is highly unlikely.

I am with you on this. 3 valves ,ok you cap the rail. what happens now when the pressure goes up? cracked rail, injector or something more expensive is right. relief valves in the system are great, you should leave it there at all costs. now a cp3 only makes 23,209 in stock form. what did you do to the cp3 to make it have more, I can tell you, nothing. just the programming feeding it, the cp3 stayed the same stock. I am not a fan of the rail cap, you want more there make a better valve,if thats the problem.

 

[Diesel Power]

could the fca be faulty and letting too much fuel in causing a press spike thus destroying the valve?

no it would set a code

 

[Diesel Power]

I am with you on this. 3 valves ,ok you cap the rail. what happens now when the pressure goes up? cracked rail, injector or something more expensive is right. relief valves in the system are great, you should leave it there at all costs. now a cp3 only makes 23,209 in stock form. what did you do to the cp3 to make it have more, I can tell you, nothing. just the programming feeding it, the cp3 stayed the same stock. I am not a fan of the rail cap, you want more there make a better valve,if thats the problem.

the stock bosch system can handle over 40k psi as is,( for a while ) except the valve :-laf :-laf

 

[TCluff]

no it would set a code

IT MIGHT BE POSSIBLE TO BE OUT JUST ENOUGH TO NOT SET A CODE, BUT CAUSE HIGH RAIL PRESSURE AT A VERY LITTLE THROTTLE COMMAND.

 

[SP Diesel]

now a cp3 only makes 23,209 in stock form.

This is just about right when the engine is running, but as soon as the engine is turned off the fuel rail pressure spikes up to 26,000psi or more when power is taken away from the CP3's control valve. This can be seen on a rail pressure gauge on stock and modified trucks.

 

[JRG]

OK excuse my ignorance, buy I'am trying to learn.



Q: Does the D-max use the same Bosch setup, if so are they having any issues? If not can we kype their valve?



JRG

 

[Diesel Power]

This is just about right when the engine is running, but as soon as the engine is turned off the fuel rail pressure spikes up to 26,000psi or more when power is taken away from the CP3's control valve. This can be seen on a rail pressure gauge on stock and modified trucks.

yes you are correct

 

[Diesel Power]

OK excuse my ignorance, buy I'am trying to learn.



Q: Does the D-max use the same Bosch setup, if so are they having any issues? If not can we kype their valve?



JRG

yes they have the same setup, except the latest from the dura max, it is better

 

[BRayls]

the stock bosch system can handle over 40k psi as is,( for a while ) except the valve :-laf :-laf

:-laf :-laf , why not make a stronger valve? a man that acts so smart should be able to do that right? now I wonder why everyone is going away from high psi in the rail, it ruins injectors. that is fact. now I am not selling a product so I don't know a thing.

 

[Diesel Power]

:-laf :-laf , why not make a stronger valve? a man that acts so smart should be able to do that right? now I wonder why everyone is going away from high psi in the rail, it ruins injectors. that is fact. now I am not selling a product so I don't know a thing.

yes that is true the injectors will fail after long periods of high psi and no relief, thats why we recomend to STAY AWAY from heavy pressure boxes with the rail cap, except for racing--or pro street. but there is much more to it than meets the eye

 

[EB]

Valve replaced, truck will start now, but something is still not right. It continues to have a tap or knock and it smokes like a freight train at the least bit of acceleration. I think I'm not getting a good spray pattern which is not giving me a clean burn. Guess it is time to think about injectors.

 

[BRayls]

yes that is true the injectors will fail after long periods of high psi and no relief, thats why we recomend to STAY AWAY from heavy pressure boxes with the rail cap, except for racing--or pro street. but there is much more to it than meets the eye

so in 2 years are you going to say ,man we should not have been running those rail caps. just as we found out that the psi was killing injectors a few years later.

 

[SP Diesel]

EB,



Does the truck throw any codes?

It almost sounds like your fuel command valve is stuck open on the CP3 allowing full rail pressure. This could take out a relief valve over time and explain the smoking and noise off idle. You would need to get a pressure gauge on your rail to know for sure tho.

 

[TCluff]

EB,



Does the truck throw any codes?

It almost sounds like your fuel command valve is stuck open on the CP3 allowing full rail pressure. This could take out a relief valve over time and explain the smoking and noise off idle. You would need to get a pressure gauge on your rail to know for sure tho.

AKA fca or fuel control actuator that is kind of what i was thinking too!

 

[EB]

It has one code showing, P0234 which is turbocharger over boost. That can be explained away because I have the Edge boost elbow in and am not running the Edge box on the truck. I believe the box has a "boost fooler" built into it to prevent that code.

I'm pretty disgusted with the dealer's shop. They keep telling me everything tests normal and there is nothing wrong with the truck. When I went to get it yesterday, they had it running with the hood up so they could hear if it was tapping or knocking. I could hear across the parking lot and they said it was normal. Sorry, after almost 300,000 miles I know what is normal on that truck.

This morning it took right at 45 seconds to start the truck, I timed it. Something is definitely not right. I'll call the dealer and see if they checked that FCA valve out.

 

[Diesel Power]

It has one code showing, P0234 which is turbocharger over boost. That can be explained away because I have the Edge boost elbow in and am not running the Edge box on the truck. I believe the box has a "boost fooler" built into it to prevent that code.

I'm pretty disgusted with the dealer's shop. They keep telling me everything tests normal and there is nothing wrong with the truck. When I went to get it yesterday, they had it running with the hood up so they could hear if it was tapping or knocking. I could hear across the parking lot and they said it was normal. Sorry, after almost 300,000 miles I know what is normal on that truck.

This morning it took right at 45 seconds to start the truck, I timed it. Something is definitely not right. I'll call the dealer and see if they checked that FCA valve out.

your injectors sound bad, but if your fca was bad you WILL set a code, also you guys are forgetting----dirt in the system can easily wipe out everything in it's path. including relief valves and injectors or anything else that fuel runs in to.