4 resistors wired correctly will provide a noticeable jump in power and not really change fuel economy – still approx 600kms to a tank. This modification was done to a Hilux that had travelled 130000kms and never a problem – although it did increase the “death rattles” on a cold morning. This mod has just been completed on a brand new Hilux with 200km on the clock plus several other Hilux’s. This new Hilux never had the rattles and still doesn’t with the modification.
This will only work on the later model Hilux’s - 2007 onwards – somebody can correct me here.
How does it work?
We are playing with the Fuel Pressure Sensor. The Sensor reports to the ECM to tell the ECM what the fuel pressure is at. The ECM will continually adjust the fuel pressure to keep it a preset mapped value/s.
The resistors create what is known as a voltage divider. They trick the ECM into thinking that the fuel pressure is too low, so the ECM responds by increasing the fuel pressure back up to what it thinks it should be. However, if you measured the fuel pressure with a gauge now, you would find that it would be higher than what the ECM reports it to be.
Increasing the fuel pressure squeezes more fuel through the Fuel Injector. More fuel equals more power. Simple.
The values of the resistors can be changed if you know what you are doing, but it has been found that the values given provides a conservative power increase without pushing the limits.
Parts required.
2 x ¼ watt 10K resistors
2 x ¼ watt 1.5K resistors
Electrical tape.
Tools required
Side cutters
Soldering iron and solder.
Method
1 Leave ignition turned off – disconnect battery if you feel that way inclined.
2 Remove Glovebox.
3 Locate the engine ECM – it’s the one with the most plugs in it.
4 The bottom connector has the 2 wires of interest – you might have to remove other connectors from other modules to make life easier.
5 Locate a Green with Red stripe (GN/RD) wire and a Red with Yellow stripe (RD/YL) wire in that bottom connector.
6 There is not much slack wire available, so work out the best spot to cut both wires so that you can successfully make new connections and or solder the wires back together again if you want. Basically don’t cut the wires right at the connector, otherwise you’ll be in a world of hurt.
7 Given the tight conditions, it is better to extend the length of each wire to make it easier to work with – perhaps some 4 core cable of similar gauge wire.
8 Follow the diagram of how the connections are made. It’s up to you whether you put the resistors on breadboard or just solder them straight onto the wires, you can even solder them onto the back of a DPDT switch so that you can turn the “chip” on and off. (Turning the “chip” on or off while the engine is running will sometimes bring the Check Engine light on and put the engine in Limp Home mode.
9 If you follow the diagram correctly, everything should work as normal, but with a bit more power. If you bugger something up, the Check Engine light will come on, so check your wiring again.
10 Find a suitable/good “earth” for the end of the 10K resistors. There are a bunch of Brown wires near the ECM which I believe to be “earth” wires.
11 Put everything back together.
12 Go and tell your mates how smart you are
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