Modified 6.4 - Air in Fuel - 7 wks without truck - please help

For what its worth.. When I got to JD's shop, my airdog was pushing 50 PSI to both of my pumps and neither leaked.. So its not always going to leak. BUT, my 2009 had 8 PSI and leaked horribly. Im with Nathannial's point.

:fustrate:

It's not likely the lines are routed wrong, only 1 real way to plumb the dd kit. Basically the factory pump feeds bank 2 the front pump is plumbed to bank 1. Then the two open ports that normally would go to the other rail are plumbed together. There's no way to route them wrong without re bending the lines. If it's plumbed wrong on the high pressure side someone tried really hard to do it wrong. It is possible to have the inlet and the return flipped.

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Just to clarify I am not talking about the HPFP lines. I am talking about the lpfp feed to the second k16.

It ran for a while without problem... It would be fine until the aerated fuel feeding the other k16 got hot causing metal to go into the system which caused the 2 injectors to go down.....


Make sure the feed from the LPFP is feeding the correct port on the added K16 pump and return is the correct return on the HPFP.


Let me know what you find .

Nathannial @ Elite said:

funny thing about that, 90% sure we figured out recently. just a fluke deal, Tadd noticed an odd change on a reman pump we got. we will see if it can be proven as the cause. if so the fix is pretty simple.

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Definitely keep us updated on this! I think a lot of guys would benefit from any info on the reman pump fixes!

Sorry for the delay, hope everyone enjoyed their Memorial Day weekend.

Here is the fuel system schematic I drew up. I obviously modified the one from the 6.4L Coffee Table book but this gives you the gist. The dealer mechanic said he couldn't begin to figure out the fuel system. I spent 10 minutes with a fiber optic camera (and knowing very little at all about the factory system) and had it mapped. The only uncertainties I have with the diagram are the internal routing of the elite fuel bowl delete (and whether it comes with the pressure regulator - perhaps Nathaniel can chime in), and the 2 high pressure outlets on the factory K16 - I may have gotten them switched but 1 definitely goes to left bank and 1 goes to high pressure out on belt driven K16.

Air in fuel only seems to be affecting left bank. I don't think dealership will be able to isolate pumps, not sure if another place could do that for that matter. It would be a chore to get to the factory pump without pulling cab (i.e. probably not possible). Do you guys see any issues with the routing??

So my thoughts are we will retest low pressure fuel pressure just to make sure the LPFP is keeping up with the HPFPs since it is so easy to do. Next would be to check injector cups unless you guys see a likely culprit in the system routing. Thanks again for all your help!

Well I can't get pdf to load properly so I'll have to address that tomorrow.

Pdf works, just takes a little time to load.

Cups are not going to have anything to do with HPFP system.

sideactiondiesel said:

Cups are not going to have anything to do with HPFP system.

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But is that not one of the few places are could be getting into the system? If only one side is affected?


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But is that not one of the few places are could be getting into the system? If only one side is affected?

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Yes in the return side of things.... but that is not his issue.

Did the new Hpfp get reversed before install?

Brenton, would a cracked cup just pressurize the return flow from the heads and not the high pressure part of the system?

White monster, what do you mean by reversed?

To all, does anyone see any problems from the routing in my diagram? Are there any tests that can be done to determine if rail pressure is holding in the left bank since the sensor is in the right bank? Do you see any reason to redo the high pressure tubing if it appears to be hooked up right?

The dealer thinks there are aeration problems because the left bank injectors are randomly dropping out and coming back when running ( individually, not all at once). Should i try to check the injectors more in case it is an injector problem? That side has 2 new injectors and 2 injectors that were just checked at rcd so I wouldn't think that is the problem. If they checked for aeration at the cooler outlet, would it show up there if a cracked cup was pressurizing the return that goes to the cooler inlet?

I'm concerned the issue might be with the factory injection pump since that feeds the left bank exclusively. Is there any way to check the pump short of rerouting everything to just run off the belt driven pump? If we isolate the pumps and run off only the belt driven pump do I have to worry about lubrication to the factory pump?

Thanks!

MT_Diesel said:

Brenton, would a cracked cup just pressurize the return flow from the heads and not the high pressure part of the system?



White monster, what do you mean by reversed?



To all, does anyone see any problems from the routing in my diagram? Are there any tests that can be done to determine if rail pressure is holding in the left bank since the sensor is in the right bank? Do you see any reason to redo the high pressure tubing if it appears to be hooked up right?



The dealer thinks there are aeration problems because the left bank injectors are randomly dropping out and coming back when running ( individually, not all at once). Should i try to check the injectors more in case it is an injector problem? That side has 2 new injectors and 2 injectors that were just checked at rcd so I wouldn't think that is the problem. If they checked for aeration at the cooler outlet, would it show up there if a cracked cup was pressurizing the return that goes to the cooler inlet?



I'm concerned the issue might be with the factory injection pump since that feeds the left bank exclusively. Is there any way to check the pump short of rerouting everything to just run off the belt driven pump? If we isolate the pumps and run off only the belt driven pump do I have to worry about lubrication to the factory pump?



Thanks!

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You could unplug each pump individually. Undo the front 2 connections and see what happens...then undo the rear plug

That should isolate them


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webb06 said:

You could unplug each pump individually. Undo the front 2 connections and see what happens...then undo the rear plug

I would think that would stop them from making pressure. That should isolate them


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MT_Diesel said:

Brenton, would a cracked cup just pressurize the return flow from the heads and not the high pressure part of the system?

White monster, what do you mean by reversed?

To all, does anyone see any problems from the routing in my diagram? Are there any tests that can be done to determine if rail pressure is holding in the left bank since the sensor is in the right bank? Do you see any reason to redo the high pressure tubing if it appears to be hooked up right?

The dealer thinks there are aeration problems because the left bank injectors are randomly dropping out and coming back when running ( individually, not all at once). Should i try to check the injectors more in case it is an injector problem? That side has 2 new injectors and 2 injectors that were just checked at rcd so I wouldn't think that is the problem. If they checked for aeration at the cooler outlet, would it show up there if a cracked cup was pressurizing the return that goes to the cooler inlet?

I'm concerned the issue might be with the factory injection pump since that feeds the left bank exclusively. Is there any way to check the pump short of rerouting everything to just run off the belt driven pump? If we isolate the pumps and run off only the belt driven pump do I have to worry about lubrication to the factory pump?

Thanks!

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The front pump needs to be reversed for proper operation. The rear cover needs to be removed and the ring flipped. Did this happen?

White_monster said:

The front pump needs to be reversed for proper operation. The rear cover needs to be removed and the ring flipped. Did this happen?

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I think you might be on to something Shane.

MT_Diesel said:

The dealer thinks there are aeration problems because the left bank injectors are randomly dropping out and coming back when running ( individually, not all at once). Should i try to check the injectors more in case it is an injector problem? That side has 2 new injectors and 2 injectors that were just checked at rcd so I wouldn't think that is the problem. If they checked for aeration at the cooler outlet, would it show up there if a cracked cup was pressurizing the return that goes to the cooler inlet?

Thanks!

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The elite low pressure system recirculates the return fuel back the the regulator if a cup was broke the air could renter the system there. Crack the line on the fuel cooler and see if you get air.

White_monster said:

The front pump needs to be reversed for proper operation. The rear cover needs to be removed and the ring flipped. Did this happen?

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Perhaps Jared will chime in on this. RCD didn't do the work but he is familiar with the truck. I don't know but will try to contact the seller and ask.

Jonnydime said:

The elite low pressure system recirculates the return fuel back the the regulator if a cup was broke the air could renter the system there. Crack the line on the fuel cooler and see if you get air.

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The dealer did run a test by hooking a clear tube to the fuel cooler outlet while running and said fuel didn't appear aerated.

The pump was reverse rotated. I reverse rotated the first pump, the front pump was then replaced a few months before Ryan bought the truck and was also reverse rotated.

sideactiondiesel said:

Cups are not going to have anything to do with HPFP system.

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If it's putting air/compression back into the pump, though it is technically a low pressure issue.

Jonnydime said:

The elite low pressure system recirculates the return fuel back the the regulator if a cup was broke the air could renter the system there. Crack the line on the fuel cooler and see if you get air.

Click to expand...

The quote above is why I said a cracked cup could cause the issue, plus I had it happen to me as well.
if the problem is limited to one bank I doubt that is the problem though.