I need to locate the ECU ground wire in order to complete my Apexi Auto Timer installation. I downloaded the ECU harness diagram from ravensblade.com, but it doesn't specify which one is the ECU ground.

A little help, pweeez?

its probably just the ground that you ground to some metal. is it a black wire? just get one of those wire thingies that u can put a bolt through and use one of your floor board bolts as a ground.

Brent

Sorry, wrong answer :D

The directions specifically state that if you want to use the automatic idle time feature of the turbo timer, that you need to use the ECU ground and rear O2 sensor. I've got it grounded to the frame right now, just so I can use it, but I need to find this wire to make it 100%.

Anyone?

There should be no difference between connecting to the frame and using the ECU ground. The ECU ground is probably connected to the frame as well. Come to think of it, I think the ECU is grounded from the case that it is in, which is bolted to the frame.

I was thinking that it shouldn't matter either, but I'm no electrical engineer so I was a bit perplexed by this. My only thought was that it needs some sort of voltage measurement from the ECU wire specifically, to get an accurate A/F ratio...well, as accurate as you can with a non-wideband sensor. I guess I'll try hooking up just the O2 sensor wire to see if the A/F readings make any sense.