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I have a truck that wasn't holding rail pressure. We removed the banjo bolt near the PRV and we got fuel leaking from the fitting at idle. We figured it was a bad valve so we ordered a new one. The new one leakes as bad as the old one. What are the odds we got a bad valve from the dealer, 1 in 1000? The only thing I can figure is that the sealing surface in the rail is bad.
I thought about sealing the banjo fitting with a bolt or welding the banjo bolt shut but I didn't know if that would work. I don't know if the washers will seal since it is after the valve and really not meant to hold that kind of pressure.
Anyone know of a solution without buying a new rail? Could it be something else that I am missing?
Simply taking the bolt out of the banjo will not let you determine the source of the fuel. The return line is under return pressure from the CP3 and injector valley return. Return flow from either of those places will dribble out of the banjo making you think you have a faulty valve.
NOW, if you're sure it is in fact coming out of the bung on the side of the rail, then you need to take a close look at the face that the valve is supposed to seat into.
I've seen quite a few of the 5.9L trucks have a cracked rail where the relief or pressure sensor threads in. If that face is cracked it will act like a failed relief valve.
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2001 QCLB 3500 Dually 4X4, Stock, FOR SALE 8000 OBO
2003 QCLB 2500 640 HP / 1125 ft/lbs SOLD!
Friends don't let friends buy VP trucks....
Parts for sale Van Aken SmartBox, Stage II Monster Pump, and FASS 95, 03-05 Banks 6Gun, TST PMCR w/R37 remote also have another full one w/R49. Parting out 08 3500. http://www.cumminsforum.com/forum/07...-part-out.html.
I moved the return line away from the rail to be sure is was coming from the bung and not just out of the line. I guess I'll have to take my Shibby intake back off and see what I can see in there!
On a side note, there was more fuel coming from the line than the specs say there should be. The truck has an 85% over stock pump. Would the bigger pump cause the extra return?
Yes, the return from the pump is caused by surplus flow from gear pump on the back of the CP3. When that pump is modified, at an idle it can push more fuel out the Cascade Overflow Valve and into the return line.
When you have the intake off take a can of brake parts cleaner and clean the seat very carefully in the end of the rail. Look for any hairline cracks or anything that may be present in that face.
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2001 QCLB 3500 Dually 4X4, Stock, FOR SALE 8000 OBO
2003 QCLB 2500 640 HP / 1125 ft/lbs SOLD!
Friends don't let friends buy VP trucks....
Parts for sale Van Aken SmartBox, Stage II Monster Pump, and FASS 95, 03-05 Banks 6Gun, TST PMCR w/R37 remote also have another full one w/R49. Parting out 08 3500. http://www.cumminsforum.com/forum/07...-part-out.html.
Well, no cracks that I can see but it does look like the face of the rail where it seats is scored so its probably not sealing right. Guess I gotta buy a new rail?
might want to check the injector feeder tubes that connect to the injectors (under the valve cover). I had a prblm with the hold down bolts being very loose (barely finger tight) and the tube would start to rattle and unseat at certain pressures.
Just a thought...
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'08 6.7L 2500 QC SB. Black Maxx, II Stg 2, Shibby Stg 1 and Tube GHD, TVD, BD IC, 4"TBE, ADII, Fluidampr, S&B CAI, Carli 2.0 w/ springs, swaybar, and stabilizer.
might want to check the injector feeder tubes that connect to the injectors (under the valve cover). I had a prblm with the hold down bolts being very loose (barely finger tight) and the tube would start to rattle and unseat at certain pressures.
Just a thought...
have seen this many times this is a comon problem i would check that first before buying a rail. this will also cause low rail pressure.
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2010 2500 4x4 6.7L g56 shes got atouch to her
have seen this many times this is a comon problem i would check that first before buying a rail. this will also cause low rail pressure.
Yes, but this wouldn't cause fuel to come out of the bung where the banjo bolt connects to the rail. The only way fuel would leak from there would be if there was a problem with the PRV.
how much fuel is coming out the rail it should be 1 drop per second. also what did you troque the valve to? i just have never seen cummins give another bad one out of the box but i have seen odder things working there so maybe they did.
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2010 2500 4x4 6.7L g56 shes got atouch to her
how much fuel is coming out the rail it should be 1 drop per second. also what did you troque the valve to? i just have never seen cummins give another bad one out of the box but i have seen odder things working there so maybe they did.
Much more than a drop per second!
The first valve that was shimmed, I don't know what it was torqued to, I didn't install it. I installed the second one and torqued it to whatever it was the service manual specifies, I don't remember now.
Is it possible for the rail to be bad, but not leak at the fitting? I had a bad relief valve, the new one from cummins leaked to. So we shimmed the old one and it held for a month or so, but now I am having low rail pressure issues again... :\
Is it possible for the rail to be bad, but not leak at the fitting? I had a bad relief valve, the new one from cummins leaked to. So we shimmed the old one and it held for a month or so, but now I am having low rail pressure issues again... :\
Mine didn't have an external leak but when I removed the banjo bolt, fuel leaked from the bung in the rail because it was leaking past the valve. The valve wasn't opening because this was at idle so it must have been leaking past the valve where the valve seals to the rail. A new valve didn't seal either. Upon further inspection, I found that the sealing surface inside the rail was scored which is why it was leaking.
Make sure the valve is torqued to specs, not over or under. I think when the guy installed the shims in the valve the first time, he over tightened it and messed up the rail. I know for a fact he didn't use a torque wrench. That's the only thing I can figure anyway.
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