I've been reading and reading trying to figure out what's causing my hard starting issues. I have to crank and crank the truck and give it throttle to get it started. I figured out that I must be getting air somewhere. So I stated to look for fuel leaks. Sure enough I'm seeing 6 inch puddles under the truck after sitting for 8 hours. I crawl under the truck and wouldn't you know it it's leaking a top of the fuel tank. There is a wet fuel stain running down the drivers side of the tank right smack dab in the middle. I'm assuming I must have a line leaking where it comer out of the tank.

Can you guys tell me what to expect when I drop the tank? I'm thinking that's the only way to get at it besides cutting a hole in the bed(which is a option). Are the lines flexible so the tank can be dropped easily. I'm assuming I'll have to replace the bad line. Can the lines be spliced or do I have to replace the whole thing. If so how long are the lines. Thanks.

 

I found a picture posted by happy camper on another thread but I can't seem to figure out how to post it here. Is this what i can expect on my 90. I'm hoping is just one of the rubber lines. Would a leaking line cause the hard starting problems?

 

the leaky fuel line could vary well be the fix, If not its part of it.....unless it only leaks when the tanks full! then you have a filler neck/ hose problem

 

My experience is with a 91 D350 2wd I do not htink there are major changes. In the picture you are looking from the passenger side with the cab to the right.

In the middle of the tank is the sending unit (white). On mine I have the fuel line and a return line connected to the sending unit. The tank straps have a bolt on the crossmembers and the other end of the strap is T shaped and goes into a slot.

I found the fuel line relatively easy to remove as it has a clip and pulls off. The return line was a little more tricky as mine was a little buggered up. There is a little plastic peice that is supposed to slide into the fitting to release the spring and catch.

The tank comes down easy and there is a little slack, but you will need to support the tank adequately.

Good Luck,

 

At $3 a gallon my tank is never full... Seriously though, it's not leaking from a full tank for sure.

 

Looking at that it looks like it's leaking right at the sending unit. It's leaking right now and my tank it below an 1/8 so it must be the feed line or the fitting between the tank and line.

 

Thanks Gordon for the reminder. i forgot that I had that picture on another server and not at home on my machine.... Hope this helps a little.

The hoses are flexible and they are short pieces that connect to a short steel line attched to the frame. From there the hoses go up to the engine compartment.

 

Could be feed or return.......return line leaking, would take a lot longer to make a no start problem

 

I believe (can't remember exactly) that the return line terminates 3 or 4 inches above the bottom of the tank inside of the sending unit. I would think that if the return was leaking that far back it would not effect starting as that is a long way for air to travel. I would also think that if the return was leaking, you would see increased fuel loss while running because it would have more pressure when compare to when the engine is stopped. If the fuel line has a leak, the lift pump would draw fuel, and any air and you could see your hard start. Anyway, you need to drop the tank to fix it.

 

Good point! It would Probably be leaking just setting there idling if it was the return!

 

Okay, I crawled underneath it last night. The top the tank and sending unit are dry. They rubber lines seem to be dry but the one steel line is rotten and wet. It's the line that goes to the rubber line that is towards the front of the truck on the sending unit. Anyone know if that is the feed or return, without me having to trace the line all the way back to the pump.

It looks like there may be enough room on top to the tank to get my hands in there and remove the hose clamps off the rubber lines. I'm hoping to just replace the steel lines with the simplest and cheapest replacement. What are my options? Can I just run new rubber lined and use double barbs and hose clamps to attach it to the rubber lines on the sending unit and pump?

Thank!

 

I'm not positive but i think that the lines are diff sizes and if thay are, then the biger line will be suction(pump feed) and the smaller one will be return.

 

That line is the return fuel line. It is the line on the left in the picture above.

Any hose you use, be sure it is rated for diesel, and if you are planning to use any bio-diesel, I would replace the hose with one rated for that.

 

They sure looked the same when I was looking at them. It appears the leaker is the one on the left in Happycampers picture. But it was pretty wet and it's tough to say when the steel lines are so close together. I'll just replace both of them.

How do I bleed all the air out after I replace the line? Can I put a pump bulb in line to speed up the pumping? If so can it be permanently left in line?

 

Pump bulb? not shore what that is but if you pump the lift pump lever enuff and have the bleed screw open you'll get it done!