wiring in AFR gauge
14 June 2008, 08:11 PM
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The live to your AFR should be taken from B136 pin 25 at the ECU which is 12v only when the ignition is on. Use a 2A/3A in-line fuse to the AFR.
The O2 sensor signal wire is on B136 pin 21 and is white with silver flashes.
The earth is critical to the correct operation of the AFR as the AFR will read the voltage between the O2 sensor wire and whatever you connect your AFR earth to. I found the earth wires used by the ECU are all unsuitable as when the car is running they can be up to 100mV higher than earth measured at the battery terminal which is massive in terms of the voltage range of the O2 sensor. On my MY00 I have fitted some supplementary earthing cables from the battery negative terminal to the engine block and to two points on the chassis ( not because of the AFR but because bad earthing is a common problem with these cars ). The ideal earth is the negative terminal of the battery but I wanted to keep all wiring in the cabin. Although not normally recommended I used the chassis close to the ECU as an earth which ( probably helped by the earthing kit ) I found to be less than 5mV different to the battery negative terminal with the car running.
If you do a search on here for 'MY99 ECU pinouts' you'll find the pinouts on your ECU plugs.
Kevin
You'll have to tap into the wires at the ECU. Trim some insulation off the wires, wrap your AFR wires around, and solder for best ( no worrying about it later ) results.
The O2 sensor signal wire is on B136 pin 21 and is white with silver flashes.
The earth is critical to the correct operation of the AFR as the AFR will read the voltage between the O2 sensor wire and whatever you connect your AFR earth to. I found the earth wires used by the ECU are all unsuitable as when the car is running they can be up to 100mV higher than earth measured at the battery terminal which is massive in terms of the voltage range of the O2 sensor. On my MY00 I have fitted some supplementary earthing cables from the battery negative terminal to the engine block and to two points on the chassis ( not because of the AFR but because bad earthing is a common problem with these cars ). The ideal earth is the negative terminal of the battery but I wanted to keep all wiring in the cabin. Although not normally recommended I used the chassis close to the ECU as an earth which ( probably helped by the earthing kit ) I found to be less than 5mV different to the battery negative terminal with the car running.
If you do a search on here for 'MY99 ECU pinouts' you'll find the pinouts on your ECU plugs.
Kevin
You'll have to tap into the wires at the ECU. Trim some insulation off the wires, wrap your AFR wires around, and solder for best ( no worrying about it later ) results.
Last edited by c_maguire; 14 June 2008 at 08:16 PM.
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