I've got a project I'm working on thats will be using a Tune Port Injection setup and the fuel pressure before the regulator is around 100 psi or a little less. would this be a problem for the stock electric dual tank switcher in 70's or 80's dual tank pick-ups? the order from tank to engine will be tank(s) switcher, electronic fuel pump, regulator (built into the TPI) then the fuel rail etc. the fuel pump only pushes 100 psi, I dont hink it pulls that hard. This shouldnt affect the switcher valve should it?

I would look at one from a diesel setup with dual tanks. I think this valve is more of a pressure type. Are you gonna use any type of pump in the tanks to supply the main pump or just try the one on the rail? Reson is I'm thinking about putting a tpi or tbi on my dually that I tow with. I was worried with the frame mounted pump having to pull fuel from the tanks.

well, my buddy is running a tpi with the hi pressure pump in a blazer but its only a single tank setup. Theres no intank pump in that truck and his inline pulls fine. im just curious about the switcher valve. theres a difference also, tpi needs a minimum of like 45psi after the regulator. more for modified setups. a tbi only needs 12 psi if I recall correctly.

Sounds good to me since you are plumbing the valve on the suction side of the pump. One problem might be if the pump can suck fuel fuel that far.What kind of pump are you running?

If the regulator is set at 45 psi that is the maximum that you will see in any part of the system. Your pump is capable of a maximum of 100 psi...those are normally "dead head" #'s (fuel line completly blocked).

But the switcher for a carb setup isn't made to take much pressure at all. I would look at a switcher from a newer MPFI truck (like a vortec).

My buddy blew out the switcher when he put in Vortec injection... 60 psi I think. The valve simply can't take it.

What he did was put a check valve on each tank feed, and tee the tank feeds together. The switcher now only switches the return lines and pump power.

with all the trouble why not just put in a manual valve to switch it if it can't handle it?

I'm pretty sure that the diesel valve is setup to handle pressure on the return side of the valve, or look at maybe one of the 88-91 crewcabs that had a tbi and dual tanks. I'm gonna have to find a valve that works also for my truck when I get around to doing the fuel injection swap.

I would think that the return line pressure would be negligible. As long as the return line is big enough.

The switcher my buddy blew up was a TBI one :rolleyes:

AFAIK, there's only two versions of the tank switcher. One with return lines (6 fittings) and one without (3 fittings).

thanks for all the info guys, this helps a lot. so far I've narrowed it down to checking into a diesel switcher, a manual ball valve type, or the check valves and tee'ing them together. Can you give any more info on this check valve setup? which ones he used etc?

Just little brass stuff like this:
http://www.specialtymfg.com/check_valves_brass/Default.asp

Must have got whatever brand the local autoparts store carries. He might even have got them at Home Depot.