Hey everyone, I am hoping I might get some help with this. Here's the situation, I'm installing a HHO generator for better MPG and it's time to hook it up to the O2 sensor wires. Before I connect the EFIE (Electronic Fuel Injector Enhancer) I have to find the hot wires for the each of my four sensors. The wires are Gray (ground), Black (sensor), and 2 White (heater). I'm trying to figure out which of the heater wires is the ground and which is the 12V wire. What is the best way to do this since there is hardly any room without getting burned by the exhaust pipes? Do I need to have the vehicle running? Keys turned on but not started? Harness still plugged in? Or unplug the 4 prong sensor harness? I have tried/am trying to find someone that knows what the color of the wires going into the O2 sensor hookup (hopefully that makes sense). For the upstream sensor on the driver side one of the wires on the harness going to 1 white wire is brown w/ a light green stripe, the other white wire has a black w/ light green stripe. The downstream sensor has a black wire w/ blue stripe and the other white one is black w/ a white stripe. For the pax side upstream 1 white wire goes to a black wire while the other goes to a light purple wire w/ a purple stripe. The downstream sensor white wires go to 1 black and the other to a blue wire. I have called multiple dealerships and part stores to see if anybody could help. I have also checked in the chilton/haynes manual with no luck on color coding wires and what each goes to. Any help with this is greatly appreciated. I would like to get this figured out before I have to leave out of country. Thanks in advance for the help.