Maxforce 13 fuel issues

Are you able to road test with any diagnostic software recording? I would like to see your fuel pressures and other performance specs when this is under load.

 

I have not been able to get that done yet. I can say this though, I drove the truck about 30 miles without the fuel filter out and my trip mpg went from 4mpg to 7.2 mpg. It was a little highway and some city.... Bobtail, hard to tell on the power without a load. I am just trying to get the air gone first and then go from there.
I have wondered about the proper filter for this pump on the primary side and whether it is matched right. The secondary filter is 10micron and I believe the first one is 25 or 30 micron. If it is wrong would the pump be able to pull air in over the top of the tube inside the filter. I know I have the right one in but I was just wondering about the proper spec. I will have a new filter housing next week. It's just crazy that it has done this on every filter housing I have installed. I reinstalled the simple screw on filter housing today just to re-test that with a bigger and thicker clear hose. That housing or filter could be leaking air. Same results. I think I found the right size of o-rings in a hydraulic o-ring assortment kit at my local very good auto parts store. I guess they are Boss rings.
I almost forgot that I did get the codes scanned a long time ago and it said the first stage fuel pressure was 100psi. (no codes present). I had the same air bubble problem at that time. I was not able to do a road test then.

 

Davco filters (paper element) come in 7, 10, 25 and 50 micron. Maxxforce takes the 25 micron filter for your Davco 382. See Davco chart.
Filters - Product Support (davco.com)
"I will have a new filter housing next week. It's just crazy that it has done this on every filter housing I have installed."
The housing is not your problem. If it was the housing changing it would have solved the problem.
What are you not changing when you change the housing? The fittings and o-rings. I would have purchased the fittings before the housing. You may be able to tape the fitting threads even with an o-ring. Send a pic of the fittings and o-ring.
Boss rings?? Something like after 2017 some models use Voss fittings.

 

I have tried everything, housings, fittings, o-rings, bottom seals, thread sealant, bowls, filters, caps, and more.
The prices Navistar wants for little things like fittings makes want to puke. There is nothing wrong with the fittings. Three different units, same results.
Boss, Voss, call them what you want they measured the same as the original, none of the other ones did. I don't even care if they will hold up to long term diesel right now I just need it to stop sucking air. I wonder how many of these has this problem and no one knows it because that little primer bowl gets dirty and you cannot see the air.
I have not tried a brand new housing, only used ones. I may be getting very unlucky or there is a weak point on these units that I cannot find. Or the fuel pump is pulling way to hard. I have been on and off of this problem for months. I have pictures and videos but I cannot post a video.

Fitting Fuel Outlet*For 5/8 Tu – 3578152C1
Fitting Fuel Outlet*90 Deg Vos – 3559213C2
This one says Voss

 

I mentioned fittings because you said the o-rings are not sold separately from the fittings. Online there is The O-ring Store. They sell kits with rings for all kinds of fluids. Probably best to contact them and tell them what you need. Site is overwhelming.
So you have tried everything but a new housing or new LINES. Consider the lines.
Ponder this. The air is not the problem. The mileage goes up without a filter because there is no restriction. The pump is weak and does not provide enough fuel with the filter because it needs a lot more suction to pull with the restriction of the filter. Or because there is no restriction it is not sucking air.
What would be interesting and telling is what the fuel pressures are with and without a filter connected.

 

"The pump is weak and does not provide enough fuel with the filter because it needs a lot more suction to pull with the restriction of the filter." God I hope that's not it but that has merit and I have pondered that. I have read story after story about these pumps being bad and it make me wonder why, are they pumping air?
About the fuel lines I removed them and replaced all of the o-rings; pain in the ###. I have used a short clear hose on the end of the line going in to the filter and I have used a long clear line from the filter back to the fuel tank; no air present until it leaves the filter housing so it is not the fuel lines.

Yes the pressures would be very interesting. Thanks for the tip about the o-ring store.

 

I finally found someone with ServiceMaxx software that could see some data. They could not do a road test snapshot though. I did learn a few things, the high pressure pump looks good. It goes up to 31 k psi. and stays with the commanded pressure.
The primary pump shows 120psi. Is that to high?? Idle pressure is 100psi. I believe the pump is sucking some air in through the top of the fuel filter intake pipe stand inside the filter bowl. But not sure why. Restriction somewhere or something else?

 

I think it is pulling in some air through the top of the intake pipe stand inside the filter bowl. Remove the filter, no air. Filter in air is seen in the clear primer bowl. when I had a clear line going from the filter housing to the primer bowl you could see either a stream of air or it would come in spurts every few seconds. I had a clear line going in to the filter housing and there is no air before the filter housing.

 

What other specs. would you like to know?

 

I would like to see what the high pressure fuel pressure is during a road test to see what it makes under load and full engine time. Even a worn out pump will pass this test like this.
I check intake manifold pressure,(30 psi is ok), exhaust outlet pressure, (Should be less than 5 psi). DPF diff pressure (new DPF is about 0.4 psi, plugged is over 1.2psi) and temps to make sure they all look good during full load acceleration.
Fuel delivery pressure is ok at 100-120 psi.