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The mkiv Supra Owners Club

12v Fuel Pump Mod

Ian C

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12v Fuel pump mod


Also known as:

The fuel pump mod


What is it?

The stock fuel system of the Supra has a switched power fuel pump. Anything off-boost and it runs the pump at 9v. Anything on-boost and the ECU switches to running the pump at 12v. This is probably for pump longevity and maybe some NVH reasons. The 12v mod is where you wire the pump to always run at 12v in the belief this will improve your fuelling at high boost high revs.



A warm fuzzy feeling that you've improved your fuelling at high revs high boost for £0



It doesn't affect your fuelling one jot. At best, running the pump at a higher voltage when off boost merely shortens its life a bit. It could also affect fuelling and drivability off-boost due to overpressurising the fuel system. As the pump switches to 12v as soon as you get on boost, this mod isn't going to change the behaviour of the fuel system when positive boost is occuring in the slightest.


Additional information

Actual on-the-road testing has displayed a use for this mod. Running a single turbo and an autobox, performing this mod removes a lean spot on gearchanges. We are not sure why yet, but testing and datalogging have shown it improves matters.

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