what happens if your return line is plugged up or clogged??

[chris142]

An old trick guys did in the 60's on small cam Cummins diesels was to pinch off the return line to the tank. Would cause more fuel pressure to the injectors which would make more power. Make sure to take your vise grips off the line before you return to the yard LoL.

 

[jwsfarrier]

Along this same topic I went to switch from my forward tank to the rear tank yesterday and thought all was good. The needle moved reading full. Not long after the truck started to die. Realized something had gone wrong with my selector valve so I filled up the empty tank to pull off that . Truck ran briefly then died. Looked under the hood and noticed I had a couple return caps leaking and my fuel pressure read 13lbs! Bled it at the Schrader valve a couple times and it would run briefly then died again. Fuel pressure shoots up. The return system is definitely clogged somewhere. Could a bad selector valve somehow shut off the return line? Thanks, pardon my hijack. I'm just stumped

 

[Black dawg]

Along this same topic I went to switch from my forward tank to the rear tank yesterday and thought all was good. The needle moved reading full. Not long after the truck started to die. Realized something had gone wrong with my selector valve so I filled up the empty tank to pull off that . Truck ran briefly then died. Looked under the hood and noticed I had a couple return caps leaking and my fuel pressure read 13lbs! Bled it at the Schrader valve a couple times and it would run briefly then died again. Fuel pressure shoots up. The return system is definitely clogged somewhere. Could a bad selector valve somehow shut off the return line? Thanks, pardon my hijack. I'm just stumped

Every once in awhile my truck will die right after switching tanks, after switching the tank switch back and forth a couple times it will run again. I think if it doesn't switch fully it somehow blocks the return. A db2 pump will not deliver fuel with a blocked return.

 

[jwsfarrier]

That's good to know . All the fuel tank components are original so I'm not surprised things are worn out. I tried switching back and forth and my fuel gauge just stayed on full. My return is totally blocked so the truck just keeps dying . Is it just a matter of.rplacing the valve

 

[Fred Smith]

I had the same problem with return lines. Power for a day and then no power, fuel leaks and after spending hundreds of dollars the problem was in the tank selector valve on frame! $55.00 fixed the problem. Valve switched tanks but the return valve part of the selector was plugged up.
1994 7.3 turbo IDI. Finally hit 160,000 miles

 

[jwsfarrier]

A follow up to my earlier post. Changed out the FSV . I went with the spendy one that is supposed to be OEM. I dropped the front tank to check on the shower head and everything was intact surprisingly . I also pulled apart the old FSV to see if somethingmight have got pulled in from the tank but found nothing. Filled the tank and primed the system fired up in short order. Also, before spending a good 2 -3 hours wondering why no fuel is getting to the filter head, CHECK THE FUSE FOR THE FSV. I had replaced the fuse after the initial issue finding it had blown but forgot to check it again after installing the new FSV. Anyway, everything works like it should now. Just a matter of replacing a worn out part . Worked great for almost 30yrs