A couple years back I started having problems with my upstream oxygen sensors. The circuit they were on kept blowing its 20A fuse under the dash. Sometimes this wouldn't happen for a few days, and sometimes it would happen as soon as I turned the key to ON before even starting the car, but usually it happened about 2 minutes into my drive.
This was a few months before I was going to put new heads on the car, so I wanted to try to get it fixed before I got my tune. Unplugging the other devices on the circuit had no effect. Unplugging the O2s always made it stop. I spent days going over it, trying different things and never figured out what was going on. Eventually, I gave up, and when I got my heads, I had the tuner do an open loop tune, where the tune does not use the oxygen sensors.
Today, I think I may have stumbled across the problem. I found a piece of exposed wire in the O2 extensions which came with my headers. I replaced the wire and plugged the upstream O2s back in. I started the car and let it run for about 3 minutes, then turned it off and repeated this a few times. Fuse didn't blow. Then I drove around for about 20 minutes until she was up to full operating temperature. Fuse is still good.
My question is: With an open loop tune, do the upstream oxygen sensors get power, or could the tune actually prevent them from powering up at all? I plan on getting back under there next week to stick a test light in there to see if it does anything, but I ran out of time tonight. I really want to understand how the circuit works. My baby's getting a D-1SC in a few weeks and I need to know my O2s are working properly by then.
This was a few months before I was going to put new heads on the car, so I wanted to try to get it fixed before I got my tune. Unplugging the other devices on the circuit had no effect. Unplugging the O2s always made it stop. I spent days going over it, trying different things and never figured out what was going on. Eventually, I gave up, and when I got my heads, I had the tuner do an open loop tune, where the tune does not use the oxygen sensors.
Today, I think I may have stumbled across the problem. I found a piece of exposed wire in the O2 extensions which came with my headers. I replaced the wire and plugged the upstream O2s back in. I started the car and let it run for about 3 minutes, then turned it off and repeated this a few times. Fuse didn't blow. Then I drove around for about 20 minutes until she was up to full operating temperature. Fuse is still good.
My question is: With an open loop tune, do the upstream oxygen sensors get power, or could the tune actually prevent them from powering up at all? I plan on getting back under there next week to stick a test light in there to see if it does anything, but I ran out of time tonight. I really want to understand how the circuit works. My baby's getting a D-1SC in a few weeks and I need to know my O2s are working properly by then.