Wiring help
03-10-2014, 04:57 PM
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Wiring help I've searched, but can't seem to find something akin to my issue. 98 Formula Firebird, all stock, auto trans.
I've only had this car 2 weeks. 3rd day it threw code PO140. No biggie, I'll check/change it when it's warmer and I don't freeze the jewels off laying under it, which was today. AHA! The bank 1/S2 wasn't even plugged in! Easy right?
WTF is the plug it goes to?? There is no harness end/connector on that side that I could find. So, I nose around a bit. There is one near the bank 2/S2 sensor, same style plug. In order for it to meet the other O2 sensor, I had to feed it over the top of the trans to the drivers side. I used a meter to check voltage KOEO, it gave me the same readings as the other aft O2 plug. So I plugged it in. Cleared the code and took it for a ride. First thing I noticed is the engined revved to about 1500 when I slipped into reverse, idle way too high in gear. Same thing in drive. But around the country block and no O2 codes and no SES light either. But the trans,engine rev issue is there now. I hook up the code reader and it shows PO507, which I never had before. I crawl back under and unplug that O2 sensor. Obviously when I took her out again, the PO140 came back, but the car idles where it should.
What could be going on there, and where the heck is the connection for that O2 sensor??? I messaged the previous owner and he claims no engine or trans work, and he never had any codes. But we know how that works. All I really need is to find where that sensor plugs in, or if that was the right sensor, something is jacked up in the wiring causing the IAC code?
Any points in any direction would help at this juncture. I need to get an inspection sticker on her soon.
I've only had this car 2 weeks. 3rd day it threw code PO140. No biggie, I'll check/change it when it's warmer and I don't freeze the jewels off laying under it, which was today. AHA! The bank 1/S2 wasn't even plugged in! Easy right?
WTF is the plug it goes to?? There is no harness end/connector on that side that I could find. So, I nose around a bit. There is one near the bank 2/S2 sensor, same style plug. In order for it to meet the other O2 sensor, I had to feed it over the top of the trans to the drivers side. I used a meter to check voltage KOEO, it gave me the same readings as the other aft O2 plug. So I plugged it in. Cleared the code and took it for a ride. First thing I noticed is the engined revved to about 1500 when I slipped into reverse, idle way too high in gear. Same thing in drive. But around the country block and no O2 codes and no SES light either. But the trans,engine rev issue is there now. I hook up the code reader and it shows PO507, which I never had before. I crawl back under and unplug that O2 sensor. Obviously when I took her out again, the PO140 came back, but the car idles where it should.
What could be going on there, and where the heck is the connection for that O2 sensor??? I messaged the previous owner and he claims no engine or trans work, and he never had any codes. But we know how that works. All I really need is to find where that sensor plugs in, or if that was the right sensor, something is jacked up in the wiring causing the IAC code?
Any points in any direction would help at this juncture. I need to get an inspection sticker on her soon.
03-12-2014, 10:38 AM
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Well, after more extensive searching here, I found someone who had posted a wiring schematic of the O2 sensor connectors... specifically what color the wires should be. Big help. I had the right connector the other day. I crawled under again today and checked the plug. The wire colors were correct, so I plugged it back in to the sensor, or rather vice versa. Started 'er up and she idled perfectly. Hooked up the scan tool and checked the bank 1/S2 voltage and it was reading fine. So I cleared the MIL/CEL and took her for a hot spin around the country block. So far so good. No MIL/CEL. Maybe when I tried it the other day I didn't get it plugged together squarely and one or more of the prongs fk'd up, or I pulled too hard on it and it jacked up the trans plug... whatever. But today it was fine. I'm going to run 'er for a couple days and see what happens. It's supposed to rain here today/tonight. Some water under her may trigger a short and I'll have to address that if that was the case to begin with. Whatever the end result. I'll post up here. This site has a ton of knowledge. I've been reading all kinds of good stuff, and bookmarked a bunch of pages. 