LS swap dual tank harness kits!
 

If anybody is interested, I literally just finished a 3-gang relay kit that replaces ALL of your existing dual tank wiring so that you can run (for example) 2 1987 TBI sending units and run 2 Walbro 255 fuel pumps. I'll be listing these shortly in the FS section with pics! Prices are $319.99 for these harnesses and include a NEW 65 psi GM style selector valve!

Re: LS swap dual tank harness kits!
 

Here is the basic harness layout for it-there is a main IGN control relay and (2) fuel pump relays-a LH and RH. The control relay activates the selector switch and the pumps as well as the GM style 6-port selector valve-which btw is NOT your standard NOS GM valve or parts store replacement-the one I include is rated to 65 psi.

Re: LS swap dual tank harness kits!
 

Closeup of part of the harness-this one has leads to plug directly into the pigtails from the Walbro style replacement fuel pumps when using an 87 style sending unit.

Re: LS swap dual tank harness kits!
 

Do you sell it without the valve? I already bought and installed one for higher pressure. I was going to build my own harness but this would be a big time saver. It's for a ls swap 86 short bed.

Re: LS swap dual tank harness kits!
 

Yes I can! Without the valve cost is $65 less on either kit!

Re: LS swap dual tank harness kits!
 

You have more than one kit? Have a link or something? I'd like to see what you have.

Re: LS swap dual tank harness kits!
 

These look really nice, as always! I'll need to save some buckaroos, but I'd definitely be interested. I don't like the idea of my current factory setup where the Walbros are drawing all of their current through the 28 year old factory wiring and the selector switch.

Re: LS swap dual tank harness kits!
 

What valve are you using? Curious if it has the late model quick connect style fittings, would make plumbing easy.

Re: LS swap dual tank harness kits!
 

No-not quick dis-connect....it has the standard barbed fittings but can still be used with SAE 30R9 rated clamp on fuel injection hose which is rated up to 180 psi. I just designed this kit so I dont have a link to it per se...just getting the word out I have them available now-both short and longbox fleet side.

Re: LS swap dual tank harness kits!
 

I definitely want one. I will pm you in a few days.

Re: LS swap dual tank harness kits!
 

Ok...sounds good!

Re: LS swap dual tank harness kits!
 

These valves are rated to 65 psi and are plug and play to the 1987 GM fuel selector valves. If you buy one from AC Delco it will be marked Pollak just like the originals were. Many people have used these with the corvette fuel pressure regulator (58 psi) for LS/Late Vortec applications.

http://products.pollakaftermarket.co...n-valve/42-159

Re: LS swap dual tank harness kits!
 

The harnesses I offer are both OEM replacements as well as upgrades for late model EFI swaps. Any questions you have let me know!

Re: LS swap dual tank harness kits!
 

This LSx spec'd dual tank kit is going out tonight for a member in NM! I needed to finish drafting his harness diagram schematic for future troubleshooting and/or mods. On kits which significantly deviate from stock I design and include a color coded diagram using my graphics program-another benefit you don't get from the big harness companies! Then again, they don't offer what I do anyway!

Re: LS swap dual tank harness kits!
 

does this use the factory selector switch that is mounted on the dash beside the ash tray?

Re: LS swap dual tank harness kits!
 

It uses a factory style switch but must be on/off not momentary. As long as it does not say depress fully you're good. I thought I listed the AC Delco/GM part number for it....if not I can look it up-it's still in dealers for about $8-9.

Re: LS swap dual tank harness kits!
 

Gmachinz,
I'm struggling a little and thought maybe you could lend some insight. I've taken the path of dual tanks on my 84' 5.3 swap with the following:
1. Walbro 255's in the tank
2. 87' tanks
3. 87' sending units
4. Pollak 42-159 6 port selector valve
Now I'm a little confused about how I'm going to power my in-tank pumps and also my OEM switch says "depress fully"????? Clearly I'm a green hat as this is the first time I've ever attempted a frame off so any help or suggestions would be greatly appreciated.

Thanks
Popeye

Re: LS swap dual tank harness kits!
 

You need to use a 1987 fuel tank switch-the TBI trucks didnt use the depress fully switches-those were momentary and powered a shuttle valve inside the selector to open/close LH or RH fuel tanks ports.

Re: LS swap dual tank harness kits!
 

gmachinz,
Do you know of any vendor that I can source an 87' harness and switch from?

Popeye

Re: LS swap dual tank harness kits!
 

gmachinz,
Will your harness work as a "plug and play" solution with the 87' sending unit wiring ? If so do you have any available ? Looking to avoid the need to fabricate wiring based on this diagram that a Painless engineer drew for me today.

Popeye

Re: LS swap dual tank harness kits!
 

If you only need a harness w/o valve I’ve got them available! I’ll PM ya!

Re: LS swap dual tank harness kits!
 

You specifically state these are for fleet side trucks, are the parts any different for a step side?

I have been looking into a setup like this for a while and will be looking into this setup more next year when I get closer to putting the truck back together. I appreciate the information on the switch itself as well as I did not know the fuel injection switch was different than the carb. switch.

Re: LS swap dual tank harness kits!
 

I was reading the above - been considering swapping an LS into my truck with dual tanks. Got to ask about the stock fuel lines - would they be ok with the higher pressure pumps? I think the stock pumps are around 15 psi and LS needs about 58 psi. I would think stock steel lines are ok, but about about the rubber lines - would they need to be replaced with something else?

Re: LS swap dual tank harness kits!
 

Anyone know if the stock lines will be fine at 60 psi? I think its gonna be ok - aftermarket hose appears to be rated at 100 psi or so.

Re: LS swap dual tank harness kits!
 

you should replace the rubber lines when doing the swap. Also make sure the steel to rubber transition has some sort of hose barb. Sometimes I mildly fare the metal tube to bite the rubber.

Cheap insurance to avoid a fire or worse.