LS7 surge tank wiring

[Corsair613]

So, I gave the fuel fixings a first thorough going-over this morning and realized that installing the surge tank is going to be problematic. There's a brief sheet of instructions on how to wire it, including modifying the connections on the backs of both the fuel gauge and switch (exceedingly difficult with the dash entirely assembled) and splicing into an ECU fuel pump relay wire. I'm seriously considering just doing without the surge tank at this point.

Can anyone who's successfully navigated this particular minefield and gotten a surge tank installed and functioning with an LS7 share detailed instructions and photos of the process?

Thanks!

Ken

[huzilulu]

Great heads up (for me)... I am just working on the under dash wiring, with trying to figure out my Stalk, Stack, Immobilizer and Central Locking wiring with the dash off... I should also get the surge tank wired in while I do this (dash will probably go in during the next week)...

[deadscoob]

Stupid question; why does the surge tank need wiring spliced in for the fuel gauge and fuel pump? Isn't that a bit over complicated? Once it's wired and spliced in to the fuel gauge, what information does this wiring give you? Total in tank plus surge tank? If so, that seems a little pointless to me - it's there as a safety net isn't it?
Or is there something clever going on with it?

[Steve_D]

I'm wondering if there is some confusion between a surge tank and the fuel changeover valve unit that the Factory supply. This latter unit does interface with the fuel pumps and tank changeover switch. I don't believe the Factory setup uses a surge tank.

Steve

[Corsair613]

This is definitely regarding the surge tank and not the fuel changeover valve assembly. Here are two quick photos, one of the surge tank and its supplied wiring & relay, and the other of the accompanying instruction sheet:





I'm this close to asking the factory if they'll take the entire surge tank kit back in trade for the normal fuel system components. I just can't imagine that my occasional track excursions will require it anywhere near enough to justify its installation.

Ken

[huzilulu]

Ken

I believe the surge tank is an additional kit to the 'normal' fuel system - so even if you don't install the kit, you should have everything to install the 'base' twin tank fuel crossover switch system already...

[huzilulu]

Also, from the instructions, you may be able to get the same result by:

1) disconnect white/green from fuel changeover switch and connect to relay

2) connect black to any ground (instead of back of fuel gauge)

3) connect white to any ignition on wire (instead of fuel switchover white)

4) you will only need to connect high pump wire to low pump relay as mentioned

I think this approach means only one wire from 'under dash' and one wire from high pump/ecu area is needed to be accessed...

Someone pls correct if I am wrong

[deadscoob]

Ah so it's for an additional pump....

[deadscoob]

Corsair613 said:

This is definitely regarding the surge tank and not the fuel changeover valve assembly. Here are two quick photos, one of the surge tank and its supplied wiring & relay, and the other of the accompanying instruction sheet:





I'm this close to asking the factory if they'll take the entire surge tank kit back in trade for the normal fuel system components. I just can't imagine that my occasional track excursions will require it anywhere near enough to justify its installation.

Ken

I wouldn't go on track without a surge tank personally

[UltimaCH]

Intank HP+LP pumps eliminates the need for any surge tank and solved the fuel boiling and other nasty things happening in the fuel system. The way to go IMHO.