Truck have both a fuel pump and electronic fuel pump?

[slam59]

Just put a new fuel pump under the hood with a full tune up a month or so ago and after seeing cable that no longer is hooked up hanging down I see mounted on the frame rail an electronic fuel pump there with rubber lines connected to both ends. Do these trucks have both under hood and frame rail pumps? Also see a red wire not connected like maybe the dog pulled it off. What would the red wire go to ?

[slam59]

The truck has dual tanks

[hatzie]

Not factory
The TBI trucks had a fuel pump in each tank but no frame rail mounted pumps on the squares.

[cadillac_al]

Ingenious, a primer pump to prime the system after the truck sits for a week or so. I have been debating using an electric fuel pump for years and years because my trucks don't get used every day. I just let them crank and crank until the fuel finally gets to the carb. I don't want to rely on an electric fuel pump though. Now, a primer pump that is used only occasionally could be the hot ticket.

[Tucson38]

So how would the plumbing work on that? Would you be forcing fuel through the electric pump by using the mechanical pump? I assume you'd want the electric pump to be bypassed entirely under normal driving conditions.

[Keith Seymore]

I have a tank mounted electric fuel pump (Holley red) on both my '65 GTO and my '74 Chevelle.

I have the electric pump wired to a toggle switch. I use the electric pump during periods of high demand, like during a burnout and 1/4 mile run. The rest of the time I drive around on the block mounted mechanical pump and it simply draws through the electric pump.

Been set up that way for 50 and 41 years, respectively. The GTO goes 12.20s at 120; the Chevelle has been 9.80's at 136mph.

K

[slam59]

I happened to notice it while under the truck on passenger side. told my mechanic about it and gonna let him look at it over the weekend. Has a red wire that looks like it was pulled off or snagged by one of my dogs that lays U see the truck once in awhile. We shall see

[motornut]

my 79 had one "hotwired" in up front,by the PO
said it was hard to start after sitting week
but turn key and never stopped pumping.
found the 1/4 return line seemed expanded/split.
found splits/breaks in other lines.(red area in 3/8 carb base/charcoal line
repaired to manual only and better now.

[hatzie]

Originally Posted by motornut

my 79 had one "hotwired" in up front,by the PO
said it was hard to start after sitting week
but turn key and never stopped pumping.
found the 1/4 return line seemed expanded/split.
found splits/breaks in other lines.(red area in 3/8 carb base/charcoal line
repaired to manual only and better now.

Typical for trucks that are "loosing the prime" in the fuel system. The electric fuel pump is a bandaid on the leaking fuel lines.
I use an electric fuel pump to prime the 1990's 6.5L Stanadyne fuel filter system on my '76 & M1008... it's on a Y off the main fuel line with a shutoff valve on the filter. It's there for priming when changing the filter not used otherwise.

[cadillac_al]

Originally Posted by Keith Seymore

I have a tank mounted electric fuel pump (Holley red) on both my '65 GTO and my '74 Chevelle.

I have the electric pump wired to a toggle switch. I use the electric pump during periods of high demand, like during a burnout and 1/4 mile run. The rest of the time I drive around on the block mounted mechanical pump and it simply draws through the electric pump.

Been set up that way for 50 and 41 years, respectively. The GTO goes 12.20s at 120; the Chevelle has been 9.80's at 136mph.

K

That sounds like a good set up Kieth, nice ET's too. I assume by "tank mounted" you mean mounted near the tank, like on the frame or something near the tank? Those Holly Red pumps are the only ones priced reasonable. I don't know why electric fuel pumps cost so much.

[Keith Seymore]

Originally Posted by cadillac_al

That sounds like a good set up Kieth, nice ET's too. I assume by "tank mounted" you mean mounted near the tank, like on the frame or something near the tank? Those Holly Red pumps are the only ones priced reasonable. I don't know why electric fuel pumps cost so much.

Correct; either on a small bracket or on the "waterfall" of the trunk floor itself.

The fuel supply line comes out of the tank, through the electric pump and then on up the frame rail to the mechanical pump.

K