My dad wants to put fuel injection on his 78, and wanted to know how tough it is to run new fuel lines.

The system he is looking at says there should be a 5/16" ID return line and a 3/8" ID supply line.

a. What size is the stock fuel supply line on a 78?
b. Where is the fuel pickup and sending unit on the 78 tank? (top/side/bottom?)
c. Can the return line be plumbed into the filler neck just below the boot, so as to avoid dropping the tank?
d. I know the electric pump needs to be below the bottom of the tank, does it need to be primed as well?

Any other advice before starting this project? The faster I get his done, the faster I can get my carb fixed and back on the road.

 

I've got FI on mine, but it's a '70 so I don't know about a '78 for certain sizes. Also, I don't know what EFI system you plan on installing so I'm just talking generalities.

You should have no problem running that size line and return line. The hardest part is the section where it rises up by the frame over the rear wheels. There just isn't a lot of room - best done up on jacks with the rear wheels removed.

I think on a 78, the pickup and return are accessed through the top of the tank, although the pickup itself reaches to the bottom of the tank, of course. You will need a new pump compatible with the tank. Some folks use an in-tank pump, others use an external pump. An in-tank pump is quieter and cooler, but external pumps are easier to install. If it's an external pump, you can usually just make sure the hose to the pump has gas in it, and it will start to pump OK after a couple of seconds. Most folks make some sort of sump or baffle system so that the fuel supply to the pump never runs dry (like on a long hard turn or when the tank is low). The pumps burn out in short order if the inlet goes dry...

I also used a relay to power up the pump so it wasn't pulling full voltage over the thin signal wires. Installing and wiring the pump is about as much work as installing the fuel lines...

I'd try to use the same return inlet hole to the tank if possible. I think your tank has a rubber bladder internally, so you don't want to damage it.

You will also need a regulator and pressure gauge to do it right. My gauge is attached to my regulator.

Good luck. Keep us posted. FI is pretty reliable nowadays...

 

The stock system is 3/8 od, and 1/4 od return line, and pressures are just fine using any injection pump and stock lines, you need not bother changing them....

GENE

 

I would use an 85 intake fuel pump. It will fit on an 82 sending unit. Fuel feed pipe, fuel return line, and vapoer line with vapor selenoid (which is on the sending unit) with charcoal cannister drivers side down low by the firewall. Three fuel lines involved. I think the hard part of the job or most labor intensive would be installing the computer and wiring harness. Just my thoughts.