Fuel delivery, power problems with M105S

[RedfoxRambler]

Hey all, I have a 2005 M105S that has been pretty reliable until lately. When it's under any kind of load, it will quickly lose power and have trouble getting fuel to the engine. With the throttle up, it'll lose power until it's just barely idling, I have to let all the way off the throttle for it to catch its breath then I can do a little more work but it very quickly loses power again. We've replaced the canister fuel filter, mesh prefilter, and sediment bowl which did have a crack in it but was epoxied before we replaced it. The spring in the sediment bowl is broken and I'll get a replacement asap, but I don't see how that could be the cause of the problem. We've also bled the fuel lines, which seemed to help for a short while but not for long.

I'm not a trained mechanic and not sure how to diagnose from here, to me it seems like air is getting into the system or fuel is being restricted somehow. Any ideas where to go from here?

Also here's a video where you can hear it losing power, this is nowhere near as bad as it is if you're trying to do any actual work with it (and it's gotten worse since this video was taken): youtube.com/watch?v=CjbTf92beCg

 

[lugbolt]

Starving for fuel.

you'll need to isolate why.

If it's got something in a fuel tank, you'll have this problem.

Or it could be a lift pump failing.

Or it can be a vent issue (seen that many times on the older M/cab's)

 

[Bulldog]

Since you've replaced all the filters try to loosen the fuel cap when it's acting up and see if it makes a difference. May just be a plugged tank vent line. If that doesn't help I'd probably look at the lift pump next. May have trash in there.

 

[thepumpguysc]

Yup, sounds like a fuel delivery problem.. nothing else to do but get dirty & probably wet..
Pull the line from the tank & check the flow.. use a bucket to drain the fuel..
if its ok, move on down the line until you find the "restriction"..
Pulling every line.. IF you find a line that's brittle, replace it..
Once you get to the "supply pump/lift pump" if its electric, turn on the key & watch the flow.. it should have some pressure behind it.. not just trickle out..
Good luck.

 

[mickeyd]

It could also be algae in the fuel. I had that problem so now I add a little Bio-Cide in each tank. No more problems.