2nd Generation Specific 1986-1992 Discussion

Sensor Question

Old 02-04-2004, 02:16 PM
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When I made my downpipe, I put the O2 sensor in the first bend that I made from the turbo. I used my stock O2 sensor so I know that my microtech would have all the sensors made for an RX7 (not sure if the O2 sensor matters). When I started the car, it took a while to warm the sensor up, I figured this is right since I have a 3 1/2" DP. So it warms up and I take her out. Got the microtech datalogging and everytime I floor the car, it went from a 19.0 A/F to 14.7. No lower than 14.7 everytime. So I hooked up my Auto meter gauge and got the same, the red LEDS would be on, then I floor it, then the center 3 or 4 yellow leds would come on. I know it was running rich because you could smell the fuel out of the exhaust, but I still increased the fuel so it was barely running and it still only read 14.7.



While it was still warm, I hooked a voltmeter to it to see what reading it is getting. at idle it was pretty low, around the .1-.3, then when you floor it, it jumped to 5.



Don't get me wrong, but I was always under the impression that an O2 sensor reads between 0-1 volt.



I put a new Bosch sensor in it and it did the same thing. So I bought a 4 wire for a 02 Protege (thought it may not be getting hot enough, so I went with a heated one), and it did the same thing.



What the hell?!?!?



Any suggestions?
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Old 02-04-2004, 02:32 PM
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number one the o2 sensor matters alot if the car doesnt get a signal from it you can really **** up your car (seriously) it wont be able to tell how much oxygen is in the exhaust fumes and prolly end up either not lettting your start your car and drive it or it will pump it rich or lean. uhhh hmmmm.





i would stick it behind the catalytic converter sometimes if it was behind it in the first place that is your problem if not try retarding the timing see if it helps (dont think it has anythiing to do with it though)
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Old 02-04-2004, 03:17 PM
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Originally Posted by rx-7foreva86' date='Feb 4 2004, 03:32 PM
number one the o2 sensor matters alot if the car doesnt get a signal from it you can really **** up your car (seriously) it wont be able to tell how much oxygen is in the exhaust fumes and prolly end up either not lettting your start your car and drive it or it will pump it rich or lean. uhhh hmmmm.





i would stick it behind the catalytic converter sometimes if it was behind it in the first place that is your problem if not try retarding the timing see if it helps (dont think it has anythiing to do with it though)
Everything you just said was incorrect.



Narrow band o2s are only suppose to read from 0-1V Roadkill. You do know that the o2 is very unaccurate for tuning anything butstoich afrs( ie: cruise/low load..? Are you just tuning vacuum right now? I usually just go by the feel of the car, not the o2 sensor voltage.
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Old 02-04-2004, 05:49 PM
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Originally Posted by rx-7foreva86' date='Feb 4 2004, 02:32 PM
number one the o2 sensor matters alot if the car doesnt get a signal from it you can really **** up your car (seriously) it wont be able to tell how much oxygen is in the exhaust fumes and prolly end up either not lettting your start your car and drive it or it will pump it rich or lean. uhhh hmmmm.





i would stick it behind the catalytic converter sometimes if it was behind it in the first place that is your problem if not try retarding the timing see if it helps (dont think it has anythiing to do with it though)
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Old 02-04-2004, 06:02 PM
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Starters, I have no cats. Just a 3 1/2" pipe out the side. I'm not using it for tuning, I would just feel better if it was working. Everything else went smooth with the Microtech install, except this. It's just annoying.
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Old 02-04-2004, 07:08 PM
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Sound to me you are running to rich. Your O2 sensor will only tell you how much oxygen is in your exhaust. You keep adding fuel and your motor can not burn all the fuel and air. This is why your O2 keep going leaner as you add more fuel. Listen to all your sensors. The best one you have is youself.



Sample; Bought a used turboII a month ago. All stock. Standing from behind the car my nose and eyes tell me there is to much unburner fuel. Install a 10 led a/f gauge (light show) with a honda heated O2 sensor. Only 7-8 leds are lighted. Indicating to much oxygen in the exhaust. Notice I did not say lean. Something must be wrong with the combustion of the fuel/air. Check spark plugs and they are B*&% platinums gapped really close. Change them for stock 9's and now the a/f gauge is lighting number 8-9 led and standing behind the car now my eyes and nose senses a better a/f.



MHO the narrow band sensor is good, don't focus on just reading the a/f gauge. Narrow band can not get you exact a/f numbers but get you going in the right direction if interpreted right.

Just my .02

chuck
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Old 02-04-2004, 09:01 PM
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sleeper is absolutely right. I had the exact same problem with a microtech and narrow-band on a n/a 13B a while back and it wasn't until I began pulling fuel out that the number came down.



Redwood
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Old 02-16-2004, 12:47 PM
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Excellent. I will try pulling the fuel down and see what happens.



Thanks for the info.
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