I have a 88 gta and was wondering which wire I should tap into for my 3 wire o2 sensor. it has to be a ignition switched 12 v wire

thanks

 

The switched side of the OP switch ?
Hot as soon as engine makes 4psi oil pressure and dead when the engine off.
Other popular supply point is the switched side of the fuel pump relay

 

Radio power like everyone else....

 

what are you talking about radio power???

 

Bingo!

 

lOl

-the power to the radio

 

Straight from the "Bubba book of Auto wiring tips"
Why would you use a power supply inside the car that requires running a new wire through the firewall to the O2 sensor
when you already have one available low down on the engine block

 

which relay is the fuel pump relay and what wire should I tap into

its a 88 gta

thanks

 

Use the grey wire on your fp relay it next to the brake booster on the bulk head.

 

I don't want to get this wrong so could you tell me which relay is the fuel pump relay

here is a pic

 

The relay has 4 wires, black, grey, orange, green with white stripe.

black = ground
orange = battery = 12v+ always
grey = wire out to fuel pump (on some cars this wire is tan with white stripe)
green/white = signal wire from ECM