There isn't a tach wire. The instrument panel watches the network and displays the digital value.<p>There are two oxygen sensors. The rear sensor is narrow-band but is used only as an emissions check for sanity and that the cat is doing its job. After the cat, things shouldn't change too much.<p>I'm not sure if the front sensor is wide or narrow, but I do know that it is used in pulsed current mode. If you're looking to connect to it, I would strongly recommend not going there. Personally I would add a fitting to the DP, for a third sensor. What will you do with the information btw?<p>Tom.
the tach wire info was just an FYI for me. I wasn't really contemplating getting a tach. Btw, how did you find out about this?<p>For the A/F though, I may want to add a ratio meter but wanted to know if the existing sensors were adequate enough to tap into rather than weld a new bung onto the dp.
Yes, I surmised you wanted to add a ratio meter. What I want to know is what you'll do with the information it displays?<p>I learned what I know about the car from a variety of sources. In my opinion, Volvo can and should be a lot more forthcoming with it themselves. But that's another issue.<p>Tom.
Well, I haven't gotten my Stage III fully installed yet and I'm not sure (although it should be dependable) how well it is tuned. I don't want to run lean. If I need to, hopefully I can get the program tuned accordingly