At the end of my wits... Help!!!

[DaytonaBill]

For the past month, my return caps have been leaking pretty bad and getting worse...

I'm leaving puddles of fuel under the engine and now the stuff drips from all over the undersides of the truck when I park!

It's really bad... And the smell of raw fuel while driving is strong! That's how bad it leaks...

I've already replaced the return caps two weeks ago and checked the IP for leaks...

Some of the caps started leaking shortly after I installed them. I know that I did them right, they didn't leak for a few days before they started their **** again... I installed the previous caps when I installed the engine and they lasted about two years without leaking...

Do any of you guys think that maybe the source of my troubles might be due to a bad FSV (Fuel Selector Valve) blocking the return line back to the tanks?

Wouldn't that cause the returns to pressurize and blow the caps? Just thinking here...

I haven't been able to use the front tank because of the FSV and wondered if it could block the returns to the tank I've been stuck on?

I'm thinking about taking it apart and cleaning it, but wish I knew what size bolts to use to put it back together and should I buy some gasket sheets?

Thanks guys, I appreciate all of the help you can give me...

 

[mblaney]

I suggest pulling the return line off the last cap (where it heads back to the FSV) and put a longer hose on it. Easy to start it up and check for pressure. Then run it into a fuel can for a short trip and see if you still get leaks. This would also tell you how much flow you are getting back to the tank.

Maybe you have crappy o-rings or the wrong size? I put Viton on mine... if I remember correctly they are part number 111; any hydraulics shop can get them or McMaster Carr overnight. $6.11 for a box of 50.

 

[chris142]

Where did you get your caps?

 

[gnathv]

Did you check inside the caps, sometimes there is a sharp burr inside from when they're made.

 

[DaytonaBill]

Well guys, I bought the return line kit from southeast power systems and did stick finger in each cap to feel for anything that could cut or nick o ring, smooth as a baby's behind... Also used engine assembly lube for slipping the caps on...

That's a great idea on the viton o rings!!! Thanks, I'm going to get some, way cheaper than buying all new kits...

So, any ideas on what I need to r&r the FSV?

 

[icanfixall]

My guess is the changeover valve is the issue. you can easily bypass it. Or the return line kit is of poor quality. Just be sure you use an exacto knife to cut off the casting flash on the bottom of the plastic caps.

 

[DaytonaBill]

My guess is the changeover valve is the issue. you can easily bypass it. Or the return line kit is of poor quality. Just be sure you use an exacto knife to cut off the casting flash on the bottom of the plastic caps.

There wasn't any casting flash or ridges...

Is the change over valve the same as the fuel tank selector valve? Thank you Icanfixall..

 

[typ4]

If the valve is causing backpresure it should shut down the truck.

 

[gnathv]

I think it's old bull that has a write up with pictures on taking valve apart. You can take the return line off the valve and put it in a container to see if the problem stops before you pull the valve apart. You can also blow air through the valve and lines back into the tank.

 

[bbjordan]

Use lots of vaseline when you put the caps over the o-rings. Then they should snap into place. If they don't snap, there's a good chance they'll leak.
You can use a gentle twisting motion on the cap to help it into place.

When putting the o-ring on the injector, put the top one one first, then roll the o-ring for the bottom over the top one.

Do the o-rings before messing with the FSV It might just save you some time and effort.

 

[icanfixall]

There wasn't any casting flash or ridges...

Is the change over valve the same as the fuel tank selector valve? Thank you Icanfixall..

Yes the fuel tank selector valve is the changeover valve. To open it you need to drill out the rivets and replace them with self tapping screws.

 

[OLDBULL8]

iF you do take the FSV apart, drill out the rivets on the swedged side just enough to clear it, then punch out the rivet. use a#6 self tapping screw to put it back together.

 

[icanfixall]

Bill that is still an excellent writeup with great pics. Its help like this that keeps our rigs on the road.

 

[DaytonaBill]

Wow!!!

Thank you Bill!

I sure do appreciate that information! I was afraid to do the job without knowing what to have on hand before I start... Can't go anywhere once I start and this really helps alot!

Thanks you again, Bill!

Thank you all of you guys! You make this place my favorite go to for when I run into trouble!

Will start project in the morning, no rain and will be in the low 60's when the sun comes up... Perfect with a cup of coffee to get started... Will report back when operation fuel line is done...

Thanks guys!

 

[DaytonaBill]

Really? So if it is partially blocked, it should make the engine surge at highway speeds, right? Fuel filter light comes on and flickers seemingly at half engine speed when idling...

Sounds like the FSV is partially restricting both feed and return?

Well, will be diving into the FSV first thing and then another return line kit is next... Wish I had a bunch of O rings...

Hat tip to mblaney!