Hello,

I think my 1993 has a fuel line (air) problem, but I'm not sure. I would like to check and/or replace the fuel lines and tank unit.

Sometimes the truck seems to be low on power. The truck has the ability to run fine on the freeway but sometimes on country roads it will do 55 MPH in 4th and feel like that's all it can do. The truck should do better and this is empty, with only an extra 500 lbs of bumper and winch - no trailer.

The IP has been recently rebuilt after the rollers and cam plate came apart. The injectors are stock rebuilds with < 30Kmi on them. Max boost I've seen is 14 psi. The IP rebuilder claimed it was a 190 HP rebuild.

Some friends suggested some gray NAPA fuel line H00905-25R and H00906-25R to replace the existing hard plastic lines and quick connect, but they used this on an '86 Ford. I am wondering if this is a good hose to use or if I should try to use some hard plastic line or even buy some metal line and tools to bend it. I am also wondering if the fuel tank sending unit could have an issue sucking air also.

What are the factory sizes of the supply and return lines?

Any suggestions? I am a newbie at fuel lines and fittings so generic answers like go to NAPA aren't as helpful as specifics.

Thanks,
Brian

 

Make a fitting to put compressed air [ 3-5 lbs ] into the fuel tank , then get under truck with a flash lite and look for leaks , from tank to main pump .

 

my 91 did the same and the pick up tube in the tank had a crack in it and it was sucking air when i got to a certain fuel level

 

From what i have read on this board, this seems to be, if not common, at least not an unussual thing...

 

Did you have an intermittant problem with the fuel level and sucking air or was it always? Was the pin hole plainly obvious or did you just change it and notice the problem go away?

I think I have a similar problem, but my symptoms appear intermittant. For example, yesterday morning it was low on power and filling up the truck made it better. In the evening the fuel level was down again after a drive and the problem showed up. However, this afternoon I did not add any fuel but power seemed ok.


Brian

 

About a month after I bought my truck, the rusted metal fuel line running from the tank to the lift pump developed a hairline crack and began sucking air, leaving me stranded at work one night.

I eventually got the truck running but it ran like absolute crap. Made it home and started blowing air into the fill hose on the tank. The crack started squirting fuel.

I ended up running a rubber hose from the tank to the LP and zip-tied to the frame rail as a temporary fix.

 

Depending on how much you want to spend, how far you want to go and how long you intend to keep your truck, you could build yourself a 1/2" fuel hose system and pickup. Or a little cheaper would be a 3/8" system. You'll need to find a good fitting, hydraulic, Parker, Eaton, or other hose shop nearby. Drill the top of your fuel tank for a 3/8" or 1/2" bulkhead fitting. Or use AN hose sizes, -6 or -8. You'll need a bulkhead fitting at the fuel tank, length of fuel hose, I used Aeroquip fuel hose. Not the expensive, but not NAPA crap either. About $3.xx a foot. Measure what you need between top of tank and to lift pump. Not sure what thread the inlet to the lift pump is. I do know it's pipe thread. Taking the inlet fitting off and into the hose shop will determine what pipe thread to AN or other fitting you'll need. Real simple actually once you get there. I wouldn't worry about the return line. Keep it stock. Just plug the stock supply line. Inside the tank you'll have a section of fuel hose attached at the bulkhead, all the way to the bottom of the tank. An inline filter of some sort could be plumbed outside of the tank. Once you get the bulkhead fitting you want, it will tell you what size hole to drill into the tank. Our tanks drill easy with wood boring spade bits. Place a cup of some sort inside the tank to catch any shavings etc. I have some pics of some of this in my gallery here, and on TDR: http://www.turbodieselregister.com/u...&albumid=18647. These may give you some ideas. Dave (Wanna) might also have some fuel system pics in his gallery, as I think he did something similar.