F I Electric Fuel Pump In front of Fuel Tank Switcher?

[1972C10]

Anyone running an electric fuel pump in fron the fuel tank valve? Im gather final parts for my TBI swap and ive heard conflicting storys as to wheter or not it would work that far foward from the tanks.

They say its best to run an electric fuel pump as close to the tank as possible .. Althou ive seen technically challenged people mount them under the hood . Carburated vehicles thou.


If anyone has any info on this it would be greatly apreciated.

[SanitysBane]

well u could be like me, and use an 88 sending unit, and fuel lines, but that wouldn't work to well if you were doing both tanks, just a thought.

[Tom]

Its going to make it really hard on the pump and it will die quicker, if it works at all.

[ElGracho]

You can use the 87 sending units with camaro pumps. This gives you ~45 psi pumps using senders designed for these trucks.

I don't know if the stock fuel tank valve can handle the higher pressure, I'm trying to sort this out myself right now.

Everything I've heard says that putting the pump in front of the valve will lead to a very short pump life just like Tom said.

[1972C10]

Well if its gonna take all that ill just find a dual tank harness out of an 87 and intergrate it with my fuel pump wiring .. I have some 87 lines the valve is the same thing and they had rubber lines from the metal lines to the switcher.

I had a cheap Vatozone special on this truck infront of the switcher It ran a 454 Carbed just fine .. But on the fuel injection i was thinking it would be more strain ..

At least i just came across a good pick up pull place today I eyed me out a perfect original bumper for 15 bucks. Hopefully i can get that good of a deal on the tank harness and tanks i guess althou i could put the pump/sender in mine The FI tanks have anti slosh baffles.

[Russell]

The switchers from GM are good for up to 80 PSI (or so I've heard somewhere). If I was you, I'd get a pair of 87 fuel tanks with the TBI pumps in them already, and put them in instead, wiring it up shouldn't be too terribly difficult either

[1972C10]

Yeah thats what i was thinking .. My friend david had an 87 one ton thats how i know the 87 tanks have slosh plates.

Im assuming the wireing would be pretty well the same with the exception of the switch i guess it switches the electricity from one fuel pump to another Or perhaps a pair of relays.

I guess ill need to find a dual tank 87 to find out. Shouldnt be that difficult thou .. I Want to keep the dual tanks Its a must on a 10MPG truck.

[ElGracho]

I've heard similar ratings on the fuel valves. The only problem then becomes the 1/4" fuel return lines. This is at least on trucks from 81-86. My 80 also has a return setup but I don't remember the line sizes. (I was under my 84 today plumbing my EFI so I KNOW what it is). The factory 87 fuel switches probably have bigger return lines (5/16") and will be the way to go.

The 87 wiring is just like mentioned above, it switches power to the active pump using two relays under the hood and a unique-to-87 switch in the cab (or 88-91 crew cabs or cab and chassis trucks with 2 tanks...) The 87 tanks are also unique like you guys said with the baffles to keep the electric pumps covered.

I'm building my trucks (I plan on injecting three of them, and of course the diesel already has 3000 psi fuel injection...) and I'll be using as much of the factory 87 setup on each as I can. They built them to go 100k miles or more and I can't argue with the engineering dollars they already spent.

I'm using the camaro pumps because the original 87 pumps are only built to run at 15 psi with the factory throttle body system.

[1972C10]

I Came across a valve from an 87 it had a crack on one of the return lines so i didnt get to use it .. but was identical to the one on my 85 P/N And all.

[N2TRUX]

I just read somewhere about a system that used two pumps. It used a small low pressure pusher pump at the tank, and a larger pressure pump upstream. It was a GM system, but I can't remember what it came from. I'll see if I can find the article....

[N2TRUX]

Originally Posted by ElGracho

You can use the 87 sending units with camaro pumps. This gives you ~45 psi pumps using senders designed for these trucks....

What is the reason for the Camaro pump?

[RockHQ]

He doesn't mention which camaro pumps to use but i presume he ment the ones that are designed for TPI injection which uses ~45psi pressure compared to the TBI pumps which only need to pump ~10-15 psi.

[Jonboy]

when you use the higher flowing pump, the regulator will let teh fuel it doesn't want return to the tank. The GM TBI pumps are notoriously weak. When they wear out, you are lucky to get the 13 psi the system needs.

I replaced the fuel pump on my 82 Corvette with the cross fire injection (no jokes, please. Mine actually worked ) with a TPI pump. The difference was night and day. My fuel mileage went up slightly as well.

I think Joe needs the the higher flow pumps to work with his ram jet setup. Being port fuel injected, it will probably need to run at 43 psi. like TPI and the LT1 setups.

[N2TRUX]

Originally Posted by ElGracho

....I'm using the camaro pumps because the original 87 pumps are only built to run at 15 psi with the factory throttle body system.

Here it is. I just missed this part. Joe you want to elaborate on this? Maybe start a new thread on your Ramjet install, including the fuel system. Just in case "someone" wants to know......

[ElGracho]

Originally Posted by 1972C10

I Came across a valve from an 87 it had a crack on one of the return lines so i didnt get to use it .. but was identical to the one on my 85 P/N And all.

This could be, but it wouldn't have been from a TBI truck then. Some trucks were still carbed in 87 (commercial 454s, 350s) and the diesel uses the old style valve. The old style valve is GM part number 14029228. The 87 TBI valve is 15548979.

Rather than using the valve ordered through GM, I plan on ordering this one:
http://www.jcwhitney.com/autoparts/P...X/appId-386021

It's made by Pollak, which is the name you'll see on the one you get out of an AC Delco box too. I believe this is the same part as the 87 speced part above, but I'll have to get my hands on one to find out for sure. The good thing is that is very clearly states it is rated to do what I want to do.

[ElGracho]

Originally Posted by N2TRUX

Here it is. I just missed this part. Joe you want to elaborate on this? Maybe start a new thread on your Ramjet install, including the fuel system. Just in case "someone" wants to know......

I'll have a page on my site soon about my install. What do you mean elaborate on this?

The TPI Camaro fuel pump flows more fuel, at higher pressure, than the stock truck TBI pump. They are externally identical, so the Camaro pump drops in place of the truck pump in the sending unit which then drops in the tank. This gives you the reliablility and quiet of an in-tank fuel pump without any fancy fab work.

As I posted here: http://67-72chevytrucks.com/vboard/s...8&postcount=12

I'm putting a Ramjet intake on my 84 K10. I'll be using a Megasquirt (http://www.bgsoflex.com/megasquirt.html) computer to control the injection.

My fuel system from back to front is:
- 87 Fuel tank with baffles (I'm using the left one only to start)
- 91 TPI Camaro Fuel pump (AC Delco EP 241)
- 87 Sending unit (made for an electric in tank pump)
- Rubber EFI hose using EFI clamps from the sender to the factory steel lines (except vent is regular fuel hose)
- Spliced in 91 Camaro fuel filter
- Factory steel lines flared with an -6 AN tube nuts and sleeves very close to front right cab mount (both supply and return lines)
- -6 Braided stainless hose from frame to intake manifold

A couple notes: the factory fuel return lines on at least 81-86 trucks are 1/4". These aren't big enough for EFI. I replaced my 1/4" line on the frame with 3/8" line. Also, the vent line on 87 senders is 1/4" and 81-86 is 5/16" I had to use an adapter to connect the two. There isn't too much flow in the fuel tank vent (to the charcoal canister) so that shouldn't matter.