Gary has the EVTM's on his garagemahal website.

You can see a bunch of different wiring schematics.

351 H.O.'s had some wiring that was not as complex as the 460 'Hot Fuel Handling' system.

I still think the simplest way to get fuel to a carburetor is with a mechanical pump and the 6 port Polack valve.
You just need to wire the senders through the valve and connect the selector switch.

 

I agree but from what I was looking at it, power flowed through it to the in tank pumps and if power wasn't going through it then it wasn't making it to the selector switch and so forth.

 

You could be possibly right, is the purpose of the 6 way valve other than the switching of tanks the use of the return lines from the system already installed. Also by using this are you saying that in your opinion the in tank pumps should be enough pressure to use with the carb?

 

What I'm saying is that if you want to use your existing in-tank pumps you need to find a safe way to control them.
And you can't have them running whenever the key is on with no flow.
They will overheat and burn out, plus there is a grave danger in the case of a broken fuel line or accident.

I do not know what the output pressure of the in-tank pump is, or if it is too much for a carburetor float valve to keep in check.
Holley's seem okay up to 8 psi. Edelbrock's don't want to see more than 5 psi.


If you use a mechanical pump on the engine there is *no* pressure coming from the tanks to activate your existing dual function reservoir.
In *that case* the 6 port valve allows switching supply and return to both tanks.
You don't need *any* power for pumps. (no inertia switch, relay, PCM, or PIP signal)
It's safe, because if the engine is not turning there is no fuel being pumped onto a fire or accident scene.

Our moderator Chris has said before that he's abandoned the in-tank pumps and been able to pull fuel through them.
But maybe Dave, Gary or someone else has another simple and inexpensive solution that doesn't involve using any of the existing computer or distributor.

My & Gary's point about either *everything* works, or you abandon the system entirely....

 

I agree, Jim.

On the valve, I haven't priced them, but if you go with a mechanical pump you can use the 3-port solenoid style valve used from 80-85, as shown here: Fuel Tank Selector Valve - ???Gary's Garagemahal. You will have to use the wire going to the rear pump to trigger the valve, but that should be easy as it runs right past the point where the valve mounts. And, you will have to block off the returns.

 

Will I still be able to use the switch as it was intended originally? Only thing is I am trying to stay away (for the moment) of tearing into the engine if at all possible. I'm afraid that since the truck came EFI that I will have to get other parts to make it work with a mechanical pump. Oncew I can get it going and on the road then I can work on another motor and do it how I want. I unfortunatley don't have the luxury or time at the moment. I hate to half *** things but don't really have a choice for now. Thats why I was hoping to try and make what is there work, I never saw on the diagrams that the computer or "pip" sensor had anything to do with the pumps running. I may just have to use 1 tank for the time being just to get this thing on the road and then come up with a game plan from there.

 

Yes. The 3-port valve was wired this way: Fuel Tank Selector & Gauges - ???Gary's Garagemahal. But your system is wired as shown on Page 104 here: Electric Fuel Pump Control - ???Gary's Garagemahal. You will take the Brown/White wire that ran the rear pump and put it to the solenoid. And disconnect the Red wire going to the front pump.

 

I'm pretty sure *your*switch switches senders *at the switch*.
EDIT: Gary's link confirms that...

Blocking off the returns is not a great idea IMO.
Vapor lock, and pumps being deadheaded are the reasons for having return lines.
Adding a carb to the mix just increases the chance of flooding.

 

Note - My response was to the question of using the switch as intended. Not to the rest. And, I assumed you would use eithe a mechanical or aftermarket electrical pump w/o the in-tank pumps.

 

Yeah, this was back when I first got my truck (1981 F350 400 carb'd) and accidentally got a tank + sending unit + pump from the JY... it was accidental in that I had never before heard of the concept of an in-tank pump and had no idea such a thing existed, seemed too dangerous to me for such a thing to even exist (electric motor inside of fuel???).

But it was in lots better shape than mine so I figured out a way to use it... the pickup tube filter was disintegrated and so I zip-tied an old gym sock onto the motor's body, left the pump not electrically hooked up (still wasn't sure what the device even was).

That worked up to about 3,000 RPM and was adequate I guess to pull a trailer of firewood up the mountain passes, but it was suboptimal and so I eventually made it right (using the correct sending unit).

 

Okay maverick,
Sorry I didn't see your edit, only what i quoted.

You can see on Garys link that the computer controls the fuel pump relay.
I explained how it can tell the engine is turning.

Half assed is fine, just make sure it doesn't kill you or someone else.
Dying in a fire would be horrible

 

I have heard of people installing a fuel pressure regulator in the original high pressure system and using that to feed a carb. You would have to find the proper regulator with a return line port, and it's probably not going to be cheap. And then you would have to carefully set it to the correct pressure.

 

Here's one. http://www.jegs.com/InstallationInst...0/650-4309.pdf

I have personally never used one of these in this type of setup.

I see Amazon has it for $150.

 

But, you would have to use only one tank with the return plumbed to that tank. Otherwise you could return to the wrong tank and overflow.

 

I will admit this is a long thread and I haven't been following very closely. But if the rest of the system is stock it should work. However the original tanks were hooked up and switched, just keep that going. The engine only had one supply and one return originally, and all that was co-ordinated at the switching valve he had.

Didn't the very early fuel injection trucks with the 3 pump system use the 6 port Pollack like the diesels and 460's? Switching the low pressure part of the system and then running that to the booster high pressure pump on the frame rail? Not positive about that though. I believe the later systems with just single high pressure pumps in the tanks used the mechanical switching valve that uses pump pressure to switch.