12H-T Fuel Issues (1 Viewer)

[Doahh]

Hey everyone,

I've had some ongoing problems with my FJ62 that has a 12H-T dropped into it.
I will lose power and stall under high load after 5-10 minutes of driving, and then it is difficult to restart. After restarting I get a shorter and shorter distance/time between starting and loss of power, sometimes using the priming pump helps out and will get it started.

Now for the fun part:
I split the fuel system, running a jerry can in the cab directly to the inlet at the primer. Now instead of losing power and stalling, it runs away. Luckily the 12H-T has a butterfly valve and I could shut it down.
I popped the fuel cap after I eventually got it home and it seems like pressure was released from the tank rather than a vacuum.

At this point, my completely uneducated theory is as follows:
The fuel tank vent is clogged, when I draw from the tank and return to the tank, it creates too much of a vacuum and struggles to pull fuel causing the lack of power and stall.
When I had the jerry can, I had the tank feed plugged. The return to the tank was pressurizing the tank and it would get to a point that the fuel pushed back from the return line into the injectors causing the runaway.

Does anyone here have any thoughts or input before I take this to someone local? I've cleaned the mesh screens in the banjo bolts at the primer, changed the fuel filter, and I can't get to the in tank pickup at my home. I'd gladly take it to one of the close LC specialists but they're both 1.5-2 hours out and I don't have a tow rig.

 

[TheBussman]

Hey everyone,

I've had some ongoing problems with my FJ62 that has a 12H-T dropped into it.
I will lose power and stall under high load after 5-10 minutes of driving, and then it is difficult to restart. After restarting I get a shorter and shorter distance/time between starting and loss of power, sometimes using the priming pump helps out and will get it started.

Now for the fun part:
I split the fuel system, running a jerry can in the cab directly to the inlet at the primer. Now instead of losing power and stalling, it runs away. Luckily the 12H-T has a butterfly valve and I could shut it down.
I popped the fuel cap after I eventually got it home and it seems like pressure was released from the tank rather than a vacuum.

At this point, my completely uneducated theory is as follows:
The fuel tank vent is clogged, when I draw from the tank and return to the tank, it creates too much of a vacuum and struggles to pull fuel causing the lack of power and stall.
When I had the jerry can, I had the tank feed plugged. The return to the tank was pressurizing the tank and it would get to a point that the fuel pushed back from the return line into the injectors causing the runaway.

Does anyone here have any thoughts or input before I take this to someone local? I've cleaned the mesh screens in the banjo bolts at the primer, changed the fuel filter, and I can't get to the in tank pickup at my home. I'd gladly take it to one of the close LC specialists but they're both 1.5-2 hours out and I don't have a tow rig.

try driving it with the fuel cap loose or removed. that will test your vent theory.

 

[relaxedcruiser]

Yes - or try first to have feed and return in the same temporary can.
Have you checked / cleaned the mesh at the fuel pickup inside the tank ?
Most of the diesel pumped from the tank is ending up straight going back into the tank - and the breather has some sort of a one way valve in it.
I removed my one way valve after having some sort of a vacuum inside the tank when fuelling up. Didn't had any running issues beforehand though. It's accessible behind the right hand side cargo panel.