So i'm getting ready to make my harness. Basicly what i have is a old cut up harness that i'm going to wire each plug individually. I also uplodated my plan. My questions so far are :

1. From what i'm aware of, for each 2-wire plug, 1 of them are ground, the is ecu signal. True or False?
2. TPS, MAP, and VSS, all have ground, ecu signal, and 5volt power. Where do i get the 5volts from?
3. Injectors are ecu signal, and power also, correct? Are the power wires also 5volts?

thanks



Here's the un modified pinout. http://www.phearable.net/tech/wiring...schematics.gif

 

1. IIRC yes, other than the injectors

2. MAP = VCC1 D19, TPS = VCC2 D20 & the 12v VSS power comes direct from battery with an inline 10amp Fuse or from fuse no.1 from the under dash fuse, relay box.

3. Injectors are ECU ground, And the 12v power for them comes from IGP1 A25 or IGP2 B1 if you have saturated injectors.
If you are using peak and hold injectors the power comes from the same pins but you will require a resistor box between the injectors and the power supply. (A25/B1 ECU).

 

Spend the extra few bucks and buy the ETM from Helm. It explains a ton. If you have a race car, $40 bucks invested for properly building your harness shouldn't matter.

1. You have to be careful to assume all are this way. Some are actually powered and ECU switch ground. Some are grounded and ECU switch powered.

2. What Ghost said is correct.

3. What Ghost said is correct.

If this is a race car, why are you installing a factory O2 sensor? What engine management are you running? What gauges / dash are you running?

 

Sorry please excuse the o2 wiring. no o2 sensor will be connected. It's on s300, i'm only running boost, rpm, oil pressure, and water temp. Ghost, when you say injectors are grounded, you mean a1,a2,a3, and a5 are ground correct? all yellow/blk wires are power correct?

 

He means the ECU grounds the signal to them. Yel/Blk are power.

 

future reference for anyone doing this. IACV isn't grounded, it's powered.