relief valve

[ScottWA]

I recently lossened the banjo bolt on the valve I think. the banjo bolt is on top of that inch and a half long extension thing next to the pressure sensor right. well if so I cracked it loose and spews fuel. If it indeed is bad my first question is why because the truck has 65k on it but stock as a rock except for a air filtter upgrade. What to replace it with a block off can i shim it or ive heard of a marine one maybe. Also I notice the injection pump making more racket then most cummins is this caused by the valve also or the fca.

 

[Summit]

if its just a seep than its livable, but if it was spewing fuel @ idle than you need a new one. ive seen 2 stock trucks with less than 20k on both that had bad valves. symptoms on mine were hard start, bucking, surging at cruising speed more smoke due to less atomization. put in new valve, truck starts like day one, bucking is gone and has way less black smoke on a run now.

 

[Mark1si]

Did you actually remove the line from the Valve? My 05 spews fuel from that line but my valve is not the culpret it is comming from elsewhere!!!!

 

[Summit]

Did you actually remove the line from the Valve? My 05 spews fuel from that line but my valve is not the culpret it is comming from elsewhere!!!!

then its back feeding from the cp3. dont think it's possible though as it's suction not pressure.



if you bend that line out of the way and fuel leaks from the "relief valve" than the valve is bad.

 

[Mark1si]

In my case "Everything is fine there is nothing wrong" says Hubler Dodge.

 

[Diesel Power]

Did you actually remove the line from the Valve? My 05 spews fuel from that line but my valve is not the culpret it is comming from elsewhere!!!!

yes you do need to remove that line its the return flow line for the cp3---thats why its leaking allover. you need to connect the cp3 to the filter block to make it right, that set up is included in our rail cap kit

 

[Diesel Power]

then its back feeding from the cp3. dont think it's possible though as it's suction not pressure.



if you bend that line out of the way and fuel leaks from the "relief valve" than the valve is bad.

if its doing that then you have too much return from the cp3 and its bad, it should only return fuel when under high rpm, only alittle at idle if any. thanks

 

[angermanagement06]

I took my bolt right off and it is feeding back from the line ??

 

[Mark1si]

If you figure it out let me know.

 

[Diesel Power]

I took my bolt right off and it is feeding back from the line ??

maybe, robert p will chime in and remind me what return flow is out of spect with the cp3---im drawing a blank right now

 

[angermanagement06]

maybe, robert p will chime in and remind me what return flow is out of spect with the cp3---im drawing a blank right now

well that line hooks in to the fuel filter so can fuel come from there?

 

[JStieger]

maybe, robert p will chime in and remind me what return flow is out of spect with the cp3---im drawing a blank right now

I have the test procedure in my Reader's Rig gallery...

 

[Diesel Power]

I have the test procedure in my Reader's Rig gallery...

thanks but i need return flow for the cp3.

 

[RobertP]

well that line hooks in to the fuel filter so can fuel come from there?

fuel should not come out of the return line thats only for fuel return.

you may get a few left over drops, but should not come out with any pressure.

 

[angermanagement06]

fuel should not come out of the return line thats only for fuel return.

you may get a few left over drops, but should not come out with any pressure.

what if fuel comes out of the return line ?

 

[angermanagement06]

fuel should not come out of the return line thats only for fuel return.

you may get a few left over drops, but should not come out with any pressure.

what if fuel comes out of the return line ? could it be from the filter fuel is being pumped in to it

 

[Diesel Power]

what if fuel comes out of the return line ? could it be from the filter fuel is being pumped in to it

no it does not work that way fuel goes from the cp3 to the filter block and the relieved pressure of the valve during a high pressure event then allows fuel to also flow through the same line, they are both hooked into the same line----so fuel should only go from the cp3 to the tank and from the valve to the tank

 

[Elite1]

Is there an after market upgraded pressure relief valve available? If so, what are the advantages vs. the stock valve?

 

[F-15I Ra'am]

what if fuel comes out of the return line ? could it be from the filter fuel is being pumped in to it

Your sig says you have a 150 gph FASS. Perhaps thats why your getting extra flow in your return line due to the higher pressure of the FASS?

 

[JHardwick]

I thought this was gonna be a good thread when it started, but I'm almost as confused now as I was before :-laf



I thought my rough idle, intermittant high pingy idle, loss of fuel mileage, seemingly loss of power etc etc was gonna be because of a bad relief valve. And I would have understood due to running an EZ for almost 150,000 miles. But, based on this thread, my relief valve is good and my CP3 isn't.



I pulled the banjo bolt and pulled the line back out of the way. At idle I stuck my finger over the relief valve like you would a garden hose and got a small fine misty spray out from around my finger. At the same time, fuel was dribbling out of the return line. Not hard enough to spray to the opposite of the inside of the banjo fitting, but a good solid dribble.



Is it my relief valve? CP3? Or as RBattelle suggested, my FCA?



I finally found what sounds like a reputable shop about 30 miles away, but as usual I'm leaving in the morning and won't be back until Sunday, they can't scan it until Monday.