Paccar fuel filter doesn't stay full

[aaronb]

This is what it looks like in the housing. No way for a draw tube I can see. There's a pin on top of the filter cartridge that pushes that ball in to let the fuel flow through. There's not a big hole in the center of the cartridge to slide around that tube because of the pin and that ball in the housing.

I had a 30 micron filter instead of the 10 micron filter I have been running. It seems to be doing better with the 30 micron cartridge. The filter is staying almost full. There's a compucheck fitting on top of the housing and one by the secondary filter for helping remove air. I'm going to get the hose to connect to them and try removing any air. I wonder if at some point when the filters were changed if it has gotten air in the fuel system.

[wedaloda]

I had the same problem on 2012 Peterbilt, K37-1004 filter is 10 micron. Changed it to K37-1009 which is 30 micron and no more air in filter. This was after wasting a lot of money on new fuel lines that didn't change anything.

[Rawze]

Even Fleetgaurd (cummins) makes the FS36401v (10 micron) filter as a replacement for the K37-1004 as well as several other companies. If the micron rating alone were any kind of an issue then no one would be making them in that rating.

The statements imply it is only the micron rating itself that is/was the issue. That does not seem to make any sense. I think I would have investigated that one further and found out what the issue really was. I know lots of guys running 10-micron filters in those housings with no problems at all.

[aaronb]

I know you weren't replying to me. I just wanted to say that I didn't mean to imply in my post that the different micron rating fixed the issue. I was just noting that it was running higher. I'm going to get the diagnostic hose and another 10 micron cartridge. I'll try and remove all the air and see if it comes back. I don't know if it will help any. I know it can't hurt though.

[Rawze]

Have you pressurized the fuel tanks to 10 psi and let it sit a few hours to check for leaks?

I have also seen cracked welds at the top of the pick-up tubes inside the fuel tanks on a few trucks that allow air in too. Putting a fuel line into the bottom of a bucket and using air pressure to push the fuel out of the tank will show bubbles mixed with the fuel to reveal this.

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If it were here, would be interesting to see for myself the difference in micron ratings and to help find a possible cause.

[aaronb]

No. I'll try that. Do I have to pressurize them individually? I took the vents out of the tanks about a month ago and made sure they weren't blocked. Where the lines come out of the top of the passenger side tank there's what looks like dirty fuel. I thought that might be causing the problem. I talked to mechanic and showed him and he said it wasn't a problem. Should I replace the line and fittings for the supply line on that tank?

[Magard]

Never mind. I see it’s not a davco. Sorry

[wedaloda]

Is it possible to get air in fuel system from the engine back to paccar filter? I'm pulling fuel from bottom of both tanks with all new fittings and hoses all the way to electric pickup pump. Concerned about boost pressure increased to 38 sometimes when it normally was around 32-34. Exhaust temperature has dropped about 75' from about 750 to 675. Fuel mileage down about .5 mpg. Thanks in advance for any advice. Mr. Hagg worked on last July, replaced ceramic fuel plungers on two cyl. pump along with mmII.

[Rawze]

(02-28-2018 )wedaloda Wrote:  ...
boost pressure increased to 38 sometimes when it normally was around 32-34
...

You say you have a 2012. If it is a CM2250 then that is too much boost pressure. You should be getting no more than about 36 psi even if you try real hard. I would suggest having the programming adjusted and updated.