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Thread: M1090 seems to be starving for fuel under any load

  1. #1
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    Default M1090 seems to be starving for fuel under any load

    My M1090 seems to have very low fuel pressure at the IP as it almost stalls under any load. It acts like it just isn't getting enough fuel. I've changed both filters with no change at all. It runs at wide open throttle while sitting still in neutral but as soon as I start to drive it empty, it won't even get out of 3rd gear without bogging down. I can stop put it in neutral and it'll eventually rev back up but the process is repeated as soon as I take off again. Is there a screen on the pickup in the tank? I've thought of changing the rubber fuel lines although I don't see any seepage. I just picked this truck up so no idea how long it's been like this. Any other thoughts would be greatly appreciated.

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    Colonel spankybear's Avatar
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    Is the air filter good?
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  3. #3
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    It appears to be. I've also noticed that if it sits for a couple days, it sounds like it's getting some air in the system when I first start it. The primer bulb doesn't feel tight either after it sits.

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    4 Star General NDT's Avatar
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    Sounds like an air leak. Super bad for injection system.

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    Check the fuel lines, age causes them to crack and suck air.
    Present
    2008 M1078A1 W/W
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  6. #6
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    I'll change all the lines. The supply line appears to be newer than the others but also looks smaller in diameter? What is the correct size supply line? Can't imagine that it should be smaller than the return.

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    Colonel Duckworthe's Avatar
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    Crownfire,
    I just went through this myself and Steve in Kentucky also. This is what I did. Hose is 3/8 inch line and -6 AN fittings. I used pushlock style fittings and hose so I can make my own hoses. I also found that the Primer bulb was leaking. You can get it all at your local Parker store. They usually have the primer housing and filter set in stock. However, they don't sell the filter housing as a kit with the 24v heater element. But you can use your old one. After I installed two of these filter primer units (they would both leak air) and the fuel would return to the tank. Here is Parkers tech quote, "these primer housings are NOS. We don't sell many of these units anymore and the units that we do sell are probably on the shelf for about 10 years. We recommend that anyone who replaces or uses this unit also put an inline check valve at the tank. That way the fuel will not be able to drain back." End quote. So, until I installed the check valve I had issues starting the truck. I had to prime it every time it sat for a few days. I installed a summit racing inline check valve part number SUM-220192B. You will also need two pushlock -6AN fittings to put in the hose and then attach the check valve. Once I installed this check valve I've had no issues. Sucks to have to deal with these primer bulbs leaking air but it is what it is I guess. And they are not cheap! Good luck and hope you get it running soon.
    Eric 619-952-4337

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    4 Star General snowtrac nome's Avatar
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    my cat guy said ditch the filter and housing and put on a racor with no primer than add a cat pimer working on getting part numbers together now

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    Quote Originally Posted by snowtrac nome View Post
    my cat guy said ditch the filter and housing and put on a racor with no primer than add a cat pimer working on getting part numbers together now
    I was wondering if you had done this to yours. I remember you mentioning it in another post. Question I have where would you mount the primer?


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    Colonel Duckworthe's Avatar
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    I should have stated clearer in LAST post that I did replace my filter/primer with the RACOR unit. I purchased it through Parker store. They carry RACOR.

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