Or...you could splice into the O2 sensor. I did that on my '93, and it works beautifully. I have a 3-wire O2 sensor (not sure about you new-fangled '98 boys) on the '93. I can find exactly which wire I spliced into tomorrow, if you'd like.
Or...just listen to John, as he has one of them-there newer SE-Rs, the ones with all the electronic thing-a-ma-jiggys on 'em.
Yeah us newer SERS have them 3 wire jobbies too! Should be red, white, and black. White is the one you want to take the signal from as it is the signal wire!
On the other hand, you can do it Gregs way too, I was just told with the 95-99, the O2 sensor wires were shielded or something and they wouldnt give you a true reading. Probably a bunch of dealer BS, but I wanted to be safer than pissed!
By the way Greg, does your A/F gauge bounce around like a mofo too? Its pretty cool in idle though when you rev, just like a tach! All the ricers get a kick out of it cause it has, and I quote, " stellar LED lights". BWAHAHAHAHA! Stellar, like no way bra!
Ok, I ran mine through the hole I drilled by the brake booster, for the alarm wiring, but if you dont have one already or dont want to drill heres an alternative:
There is a grommet about the size of a silver dollar on the firewall, in the engine, on the passenger side. I believe that the wiring for the windshield washer pump goes through it but I am not 100% on that. I pulled the grommet into the engine bay then ran a wire, with enough slack to reach the O2 sensor, into the passenger interior from that grommet hole. Once inside the passenger seat, you may have to get on your back and lay your head in the floor, I did. You have to reach up behind the heater core box and feel for the wire you fed in from the engine compartment. Its a tight fit and you will cuss my name accordingly, but trust me, the wire is there somewhere. You may have to contort your hand into a shape youve never seen before, but once you get it, its smooth sailing. Just route it under the dash, without removing any pieces of the dash, over to the drver side. From there you can fish another piece of wire or coathanger down the A-pillar hole, if this is where it is to be mounted, attach the routed wire with tape, then pull it up through the dash. Wala, one A/F wire!
Of course, Greg will tell you and I agree, to save on excess wire travel and ugliness, grab a drill and drill a hole on the driver side firewall adn run it through there. Much easier and you wont pass out from lying on your head!
Yeah, mine jumps too. I have seen 4 others installed on civics, a supra, and an eclipse and it jumps around like its on crack. You can tell if its doing its thing by when the car is warmed up, rev the gas and if it goes from hella lean reading to damn rich then back you are good!
Yep, a Autometer A/F gauge is jumpy. On purpose. What the gauge does is read the voltage from the O2 sensor. In an everlasting desire to run as efficiently as possible, your ecu tries to get this signal as dead-on stoichiometric, then leans it out a tad. Perfect, lean, perfect, lean, perfect, lean...
It does that in 'normal' driving...part-throttle cruise is what it's called.
That's why the gauge jumps around so much. You're watching the ecu and O2 sensor do their jobs, many times per second.
Of course, in WOT situations, you'll only light the first rich light. By design, too.