5 ton hard to start? M939A2 series fuel system basics.

An overview of fuel system problems to look for on 939A2 series trucks, and how to address them.

[@joemcmurtrey5800]

Been fighting on ours going great video thanks.

[@JohnyLatelyCome]

Would love to see more info on these M939s

[@dmzflightmedic]

Good block of instructions.

[@TheGreenNewSteal2025]

Exactly the info I needed thanks.

[@m1pistonhead]

After changing the separator filter and inline filter on mine, it now has a lack of power and stalls when putting it into gear. It also seems quiet at idle. It start immediately when cranked. I’m assuming there is air in the fuel system but how do I bleed it out?

[@hotrodAndy]

Thank you for all the videos! I recently picked up a m923a2 bobbed with tractor air ride suspension, my abs light is on. Any suggestions on where to start?

[@tacticalrepair]

Check the wiring at each wheel end for the pickup sensors. Sometimes the wires get damaged.

[@davespark10]

Hey man, i hope ypu reply. My 5ton idled fine, but after driving for a few mjnutes it had no power and dark smoke came out, i tried shutting it off but it stayed on for a bit before shutting off after. Do you think its rhe fuel injection pump? Or clogged injectors? How would you approach this situation to fix it. Thank you! You gave me your email once but i cant find it.

[@tj742]

Another great video. I might have missed it along the way. Where did you learn all of this?

[@tacticalrepair]

T j , experience is the best teacher.

[@Carhug2012]

I had an issue with my m939 not pressuring the air tank past 45 PSI. I connectted it to another to pressurize the tanks. But it only presserized the secondary, primary was still at 45psi. Any direction you can point me?

[@tacticalrepair]

Faulty pressure protection valve.

[@Carhug2012]

@@tacticalrepair that's incredible! I'll start investigating asap! Thanks man!

[@michaelterlizzi1684]

Ty!

[@boochie123]

i have a 1986 m931 tractor accelerator pedal sticks i have to pull it up as im driving it suggestions?

[@tacticalrepair]

Lubriate the pivot pin for the pedal at the floor, and lube the bellcrank outside.

[@grantlandrice9223]

Thanks a bunch

[@tacticalrepair]

Glad it helps.

[@Frisky0563]

77 gallon

[@eijijivjiv]

My 10 mm is rounded just used the fuel line

[@MrCrankrod]

Didn't some of them have the 855 (350) Cummins?

[@tacticalrepair]

855 yes, but only rated at 250hp in these.

[@nathanielroberts480]

I'm looking wheel seals for this truck.

[@tacticalrepair]

Www.bigmikesmotorpool.com

[@nathanielroberts480]

Thank you.

[@davespark10]

Looking for fuel screw on injector pump 👀

[@tacticalrepair]

I haven't messed with that on my 5 ton. This is a Bosch MW or P-5000 pump. Just do a general youtube search for fuel adjustment on one of those.

[@andycflbulb]

Just referred someone to this...

[@creekjonsun]

Nice Mutt

[@mrandrewdennis1]

Great video we have a few military trucks come check out some of my videos on them