fuel spraying everywhere!

[JStieger]

What a weekend! Pay-to-play in a dictionary should have a picture of my truck beside it.



I was playing around on some back roads this afternoon and then all of a sudden on a WOT run I see my fuel pressure to the CP3 drop like a rock from 10 psi to 4 psi and smell diesel big time. At the same time, I see my fuel gauge start moving a lot quicker, but I left my my cel phone at home to call up some friends . I managed to make it home and used up just over 1/8 tank in 3 miles with the fuel pressure to the CP3 at 10 psi.



I pop the hood and there is diesel everywhere on the driver side with about 2/3 of the under chassis coated. Nope, no need to pay for Ziebart rust treatment.



So with the engine running I check for high pressure fuel leaks with a piece of cardboard and nothing. I then think that since I still had all my power with this happening the leak must be on the low pressure side of the fuel system. Holley blue checks good at idle = 14 psi and no leaks.



Since the Holley Blue pressure is tapped right at the CP3 feed I then start looking at the fuel bypass line as well as the fuel return line. These lines are half steel with some pretty chinzy looking rubber splices to absorb shock I guess. No leaks at their banjo bolts. It's hard to see if the rubber is leaking or rubber-to-steel connection is leaking though since the fan is blowing diesel everywhere.



Anyone else experienced this? I'm so fed up working on this in the apartment parking lot with no shop that I think I will take it into Cummins and have them go through it.



#@$%! #@$%! #@$%! #@$%! #@$%! #@$%! #@$%!

 

[Moose]

I would check ur engine oil... See if the oil level has risen or if the oil smells like diesel... Smell the exhaust. . see if it smell like diesel... Double check all ur hard lines going to and from the fuel rail... Check the rail pressure relief valve... ... . Just things I would look at if it were my truck



Moose

 

[JStieger]

Engine oil looks and smells good. Oil pressure with my manual gauge indicated no drop in pressure either when this was happening. I literally have fuel that sprayed and collected in puddles. The most puddling was on top of the fuel filter canister, whereas every other horizontal surface was wet with no puddles.



I used cardboard to check for high pressure line leaks and get nothing either. I also had my girlfriend load up the engine with the foot on brake and letting out the clutch a bit to see if I could build up some rail pressure to make any leaks even more visible, but she can't drive a manual transmission and kept on killing the truck. Anyhow, she's not talking to me now...



I'm going to let the truck sit for a few more hours and check the oil level again as it takes a while for everything to drain down.



If I am just putzing around, i. e. low rail pressure demand, my fuel pressure at the CP3 feed is now about 10 psi with some jumps up to 14 psi. So if no fuel is leaking into the oil, then it has to be returning back to the tank excessively?? I did notice last week while under my truck that my fuel return line looked damp, but didn't know if this was from previous work where diesel was spilled... so maybe if it was busted it would have less restriction and the CP3 feed pressure would be less?



Does anyone know what threads are on the top of the pressure relief valve? I want to hook up an adapter with hose and see how much is leaking past the valve? Or could I just open end the top of the valve and start the motor real quick to see if fuel spurts out?



I wish I could shut the stupid engine fan off while the engine is running because trying to diagnose this is a PITA with fuel spraying everywhere from the fan!

 

[AKAMAC]

You can "IDLE" the truck with the serpentine belt off for a few minutes w/o doing any harm. Mike

 

[Moose]

I dont really have n e experience with the rail pressure relief valve but it LOOKS like it takes a normal banjo bolt fitting... U could try getting a tapped banjo bolt and hooking up a fitting to it so u can put on a pressure gauge... . I wouldnt suggest taking the fitting at the relief valve loose and starting the truck... At idle the ECM is calling for 6000 psi of pressure to the injectors... Even a lil bit leaking past the relief valve would possibly be well in excess of several hundred psi... .



Moose

 

[rbattelle]

Wow! Okay, JSteiger, first of all relax and go apologize to your girlfriend. I know, it's not your fault and you have nothing to apologize for, but do it anyway. In the words of Hank Hill, "Part of bein' a man is doin' things you don't want to do".



Next, relax and take a nap or something. At least 30 minutes.



Then, get yourself a garden hose and some degreaser. Wash the engine compartment and the undercarriage around the fuel lines to get all or most of the diesel fuel off. Be sure to wash anything under the hood that's currently covered in diesel fuel. Leave the vehicle to dry. Don't start it up until it's dry (and don't wash it until it's cooled!!!!!!!). Make plans not to take it to work tomorrow.



Tomorrow, with the engine compartment nice and clean, go over all the fuel lines. The fact that a high pressure leak is not apparent makes me think there is no high pressure leak; if there were one, it would make itself known quite readily, I think. Start back at the tank where your Holley pump is mounted. Check both the supply and the return line carefully for signs of leakage. Move all the way up the lines to where they connect to the CP-3.



Is the CP-3 fitting still the stock banjo, or have you replaced it with an AN type fitting? If it's an AN fitting, remove the fuel supply line and plug it. Then turn on the Holley pump and re-check the supply line for leaks.



If the CP-3 fitting is still the stock banjo, then your only choice is to start the truck back up and re-check the low pressure lines for leaks. Since the system is nice and clean now, it should be much easier to identify the source.



If no leaks can be located at idle in either the low pressure or high pressure systems, take the truck for short drives around the apartment complex. Make short loops, returning after each to open the hood and check for the presence of fuel. Stress the engine with higher loads and higher RPM on each successive loop.



Hopefully, at some point in that whole operation you'll find the source of the leak.



-Ryan

 

[RankRam]

As always, that's some great advice Ryan.



Sorry for your troubles Julius, hang in there man.

 

[JStieger]

Ryan-



We kissed and made up... ! I also had a nice cold beer, which helped I'm afraid to admit.



Anyhow, I just removed the banjo bolt on top of the rail pressure relief valve. When I did, holy cow! fuel everywhere on top of it! So I started the truck up and observed fuel bubbling out of the top of this valve and down the engine block at idle. I then goosed the throttle a bit and the fuel started pouring out. Well this isn't supposed to be happening unless the relief valve is shot, I would think???? Maybe there was so much return flow that the fuel was blowing out of those cheap looking hose to steel line connections on the return line to the tank, which is why I observed wetness on these lines last week?



It was getting dark anyway so I went to reinstall the bolt temporarily and now I lost one of the washers! #@$%! And there is no part number for it! I'll wait until it is light out and start looking for it. I'll try Nick L's method of rejuvenating these washers if I can't get the part from Cummins.



I looked over the banjo bolt closely and those holes look like they were reamed out with major pressure, but I don't have a new bolt to compare to. I'll try and post pics later.

 

[Evan A. Beck]

If ANY fuel comes out of the Pressure Relief Valve at idle, it has to be replaced. There should be no flow out of there! Here's the bad news... The new part is around $350 from Cummins, if I remember correctly.



Pressure boxes... Blah! #@$%!

 

[rbattelle]

If ANY fuel comes out of the Pressure Relief Valve at idle, it has to be replaced. There should be no flow out of there! Here's the bad news... The new part is around $350 from Cummins, if I remember correctly.

$487 from Scheid!



I'm quite amazed that a leak could occur at the pressure relief valve return line and not result in a loss of power or a very obvious spraying when the engine is running. Seems to me if it sticks open you'd have virtually no power.



-Ryan

 

[JStieger]

Ryan-



Thanks for making me step back a bit - it helped! I must admit I already have a spare pressure relief valve in my parts stash @ $420 from Cummins in town here. It never hurts to be prepared even though at the time my girlfriend said, "I can't believe you bought that and you're not going to use it!" :-laf I'm going to remember that when she buys shoes or something!



Evan-



thanks for the clarification on the fuel bubbling out of it as NFG! I figured since the HPCR manual said just attach a special fitting with rubber hose barb on it that it shouldn't be too much pressure leaking through at idle since the valve would barely be unseated if it was FUBARed. All those return lines (back at cylinder head, CP3 overflow, and rail pressure relief) meet at the fuel filter canister and have to flow down that one line of same diameter back to the tank so I think I had pure return system overload!



As far as pressure boxes go, these are what I tried in order of use so it was just a matter of time I guess:



1) BDDL

2) VAC3. 1

3) BDDL + VAC3. 1

4) DD TTPM

5) Edge Juice



Interestingly, when I installed the Edge Juice on Level 5 I kept on tripping the P0193 code for "fuel rail pressure sensor voltage high" = max pressure!



When this happened today I had just finished taking off the Juice and put the VAC3. 1 back on and was test driving it when it went TU.



I think the Juice with injectors is just too much rail pressure demand. If the 305/555 Juice was just duration/timing it might be OK with bigger injectors.



Heck, what do I know? I just keep on breaking stuff!



Ryan, one thing I was thinking about not seeing a power loss on the top end is that the VA majorly cuts back on the top end on rail pressure demand to minimize EGT for the towing crowd. What I did notice was that my EGT were about 50-100 degrees hotter than normal VA operation when this first happened today. When most people lose their relief valve they get low power, tons of smoke, and high EGT so probably the little VA masked all this! Just a theory...

 

[JStieger]

pictures...

Here's some pictures of the banjo bolt off the relief valve. The smaller bolt is one off the bottom of the fuel filter canister for comparison of a strictly low pressure banjo versus the banjo exposed to high pressures. The larger pressure relief valve banjo had visible scoring that you could feel with a finger nail.

 

[JStieger]

I finally found the part numbers on Cummins Quickserve for the washers and banjo bolt by using an engine # from 2005 (the pressure relief valve is the same part since 2003):



3958987 banjo screw $0. 78

3963988 sealing washer $2. 32 (top washer)

3967317 sealing washer $0. 28 (bottom washer)



Being shipped 2nd day air since they are coming direct from the factory, otherwise I have to wait 10-14 days!

 

[JStieger]

Replaced the valve, fired up, and now there is another high pressure leak elsewhere! This is probably the second weakest connection after the relief valve. It's the line from the CP3 to the fuel rail. It will not leak at idle, but if I go around the block and get the rail pressure up and then stop and idle the fuel is pouring out from the line nut. I loosened it and retorqued it and it didn't help.



I'm so f'en ticked off at myself now as some of the boxes I've run and various combinations thereof have finally caught up with me by cumulatively eroding the fuel system over time so I have only myself to blame.



I also want to say that I strongly believe that the Edge Juice DID NOT cause this at all. It was added to an already failing high-pressure system, which further stressed things. I think the high pressure fuel system got the death wish when I stacked a pressure box with another pressure/timing/duration (BDDL) box, when I should have just left it at one box.



I'm done with trying to fix it myself and took it in to Cummins Rocky Mountain this morning to have them go through my whole high pressure fuel system. I have a feeling that there will be more leaks once the current one is fixed if I didn't do this.



For the next week I'll be riding my mountain bike everyday!



BTW here's a pic comparing the sealing surface of the old relief valve to the new relief valve. You can see that the old relief valve hole has been partially eroded away.

 

[RankRam]

Hang in there buddy!



Sorry for your troubles.

 

[KBennett]

I hope you can find the source of the problem without too much $$



Too bad you had to be the guinea pig!

 

[jrlawler]

Don't know if this will help you but the only problem I've ever had with these engines (and I'm on my fifth CTD) is that one time the no. 1 injector line developed a hairline crack where the line was bent 180 degrees. It was very difficult to spot but I finally found it and have heard from other folks that fuel lines almost always break where they bend that much. It sprayed fuel everywhere but was almost invisible at idle or no load conditions. Hope this helps.

 

[JStieger]

Don't know if this will help you but the only problem I've ever had with these engines (and I'm on my fifth CTD) is that one time the no. 1 injector line developed a hairline crack where the line was bent 180 degrees. It was very difficult to spot but I finally found it and have heard from other folks that fuel lines almost always break where they bend that much. It sprayed fuel everywhere but was almost invisible at idle or no load conditions. Hope this helps.

Thanks for the head's up! It's odd too that these high pressure leaks I have are only visible after I run around and then idle. If I was to just start the truck and idle, then no leaks!



The other weird thing is the latest leak is not a high pressure "spray" - I can put a piece of cardboard to check for them per the shop manual procedure and nothing. The fuel is just running down the fuel line like a garden hose running! I'm sure though when I'm actually driving around it's a good high pressure spray judging from the mess under my hood as well as this is the first time my Holley Blue has pulled down to 4 psi at the CP3 feed at 1/2 throttle. Before I got these leaks, it would only pull down to about 7 psi at WOT!



I finally bit the bullet and am having Cummins go through every high pressure line and connection and R/R as required. I'm really hoping they will find the things as you suggested and get it fixed right the first time rather than me muddling through the repair over the next month!



The thing that amazes me is that despite this, the engine is still going strong, but it is all the support stuff around it is slowly falling apart...

 

[JStieger]

I hope you can find the source of the problem without too much $$



Too bad you had to be the guinea pig!

I'll try to post as much info and especially pictures so other people can learn from it, not go through it, and/or god-forbid trouble shoot it before having to deal with the dealer.



Pay it forward! :-laf

 

[J.Davy]

In the picture of the rail relief valve,is that the sealing surface?I have a spare one but it is in my glove box at the dealership so I can't look at it right now, I was under the impression it was up inside of it and unless you took it apart you could not see it.