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Hey skelly, all you had to do was ask, I've got the '97 ECU pinout up on my web site already. I've also got photos of the connectors now, which I still need to upload...
re: the A/F gauge - it's telling you exactly what the sensor is reading, and that is the normal expected behavior. Our cars use cheap narrowband O2 sensors, they read pretty consistently 0.45 volts at stoich, but anything leaner or richer than that is a guessing game. The ECU is programmed to overcompensate the A/F ratio everywhere besides WOT. That is, it intentionally over-corrects each time it changes the fuel settings, to keep the O2 sensor toggling from lean to rich and so on. The ECU determines actual A/F ratio based on the number of times the signal crosses stoich, per second. Also, the catalytic converter is designed to operate with the alternating lean/rich conditions, it cycles the cat temperature and prevents residue buildup. If you used wideband sensors and reprogrammed the ECU to lock on precisely the desired A/F ratio, the cat would soon fail.
I always figured these gauges were next to useless. The only way for a human to get a meaningful reading out of this sensor is to integrate the readings over at least a 1/10th-second interval. I think a 2-3 second moving average would be easiest to read, but then the response would be slow enough that you'd also want to see the instantaneous readings. Something around .5-1 second would probably be good enough to keep you out of trouble.
Anyway, even though the sensor returns a continuous analog signal range between 0 and 1V, you really have to think of it as a binary switch. That's how the ECU treats it.
-- Howard Chu Chief Architect, Symas Corp.Director, Highland Sun
17x8" BBS RC/Leda 24-way adj. coilovers/Hye-Dra-Cyl Big Brakes: Wilwood 4-piston calipers+12.2x1.25" rotors/RRE FSTB/Top-End Racing FW/MazdaSpeed-Quaife LSD/65mm TB/Autophysics CAI/Groundz/Bi-Xenon HID headlamps/Euro Clear-corners+amber LEDs/Blazer amber fogs/JVC KDMX3000+CHX1200/Pioneer 6x9s/BCT7 Scanner/etc...
hey hyc GTS Im curious to see what color codes you have for the 97 ecu. Im trying to install my a/f and the wire that skelly used (green w/ white strip) dosent seem to exsist in my 96 center ecu plug. Little help needed
I have 96 OBDII, my O2 wires are from the center connector, top row of the connector you will see a Green wire and a Pink/white wire side by side. These are the O2 inputs.
Using the A/F gauge (yea I have one now) I tested the readouts from under the hood and then off the ECU.
I dont understand why they have one color under the hood and another color under the dash.
The big yellow wire like from the image, its the TPS
Rick_96PGTâ„¢#62
"I never apologize.
I'm sorry, but that's just the way I am."
- Homer J. Simpson
Guess I got confused when I put mine on. I believe I used the front ones. Yes...I put 2 of them on my car for appearance mod. :grin: I didn't use the mud flap tho. hehee...mine made of paper sturdy board painted black. Match with my silver bezel.
I didnt know you could tap the a/f gauge into the ecu. I tapped mine into the front o2 sensor. Would it be better to tap in the ECU (get reading off both o2s???)
------------------------Wes Fenton------------------------ No longer a probe owner, but I'm still a probe enthusiast! ----------I can't believe I made it to 9 Myrtles!!!----------
Originally posted by probesport_gt I didnt know you could tap the a/f gauge into the ecu. I tapped mine into the front o2 sensor. Would it be better to tap in the ECU (get reading off both o2s???)
The wire you are tapping into on the ECU is the wire that runs directly to the 02 censor. So you are doing the same thing just keeping the wire mess to a min.. Tapping into the rear 02 censor gets you closer to the exaust manifold. So that would be the ideal one to tap into but both will work. You only read off one sensor because there are 2 wires going to the ECU one for each 02 sensor.
The wire you are tapping into on the ECU is the wire that runs directly to the 02 censor. So you are doing the same thing just keeping the wire mess to a min.. Tapping into the rear 02 censor gets you closer to the exaust manifold. So that would be the ideal one to tap into but both will work. You only read off one sensor because there are 2 wires going to the ECU one for each 02 sensor.
Cool...did you tap into the front 02 with those wires or the rear?
what color are the rear o2 wires if not..?
------------------------Wes Fenton------------------------ No longer a probe owner, but I'm still a probe enthusiast! ----------I can't believe I made it to 9 Myrtles!!!----------
Cool...did you tap into the front 02 with those wires or the rear?
what color are the rear o2 wires if not..?
I tapped the rear 02 Sensor which is the yellow wire. The green wire is the front. on the gauge one wire is for the sensor and one is for ground (you might have 2 more for a backlight). SO basicly in the pic I was just showing both wires (one rear, one front) Just pick one. Also double check wiring colors since you have a 94 and I have a 95.
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