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Old 01-23-2012, 05:44 PM   #1
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Default Tricking Narrowband O2 Heater Circuit with Resistor?

Waiting for a bit warmer weather to get my turbo setup in the car, but wanted to do some experimenting since I get easily bored.

I'm installing my COP setup friday, and In the interest in the scientific method, wanted to see if they made a difference...

WHAT IM GETTING AT....

I wanna use my lc-1 to log af's, but not gonna waste my bung, welding it into my tiny exhaust... What is the proper way of installing the lc-1 in place of the factory o2 in my early (obdI) 95?

In previous cars, i would hack up the factory o2,and use the lc-1's nb output wire, tapped into the signal wire of the factory o2, ground the ground wire, and then tie the heater wires together with a resistor... Is the idea the same here? and most importantly... WHAT SIZE RESISTOR? Does it really even matter being obdI? I'm guessing it does matter, being it is a 4-wire o2 and not a 1-wire? Any help on the subject matter, would be a help to me... Thanks for your time... Matt
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Old 01-23-2012, 11:24 PM   #2
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Does it really even matter being obdI? I'm guessing it does matter, being it is a 4-wire o2 and not a 1-wire?
On the '94-'95 cars, the O2 sensor heater is not powered by the ECU. The heater is powered directly off of the "meter" fuse, which branches from the same power line that feeds the coils. And the heater ground goes directly to ground at GP2.

So it does not matter- you can ignore the heater wire altogether and the ECU will not know the difference.
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Old 01-23-2012, 11:50 PM   #3
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Could you be certain about that joe? 15/17 scare me. I can't tell if they are just referring to it as a heated sensor, or if it means more. Just because there is no modern p-code slang, like "o2 sensor heater circuit", doesn't mean that this won't trip something up. Again, just concerned about it being 4-wire sensor, and not a 1-wire.



1994/1995

01 IGF signal
03 SGT signal
04 SGC signal
08 Mass Airflow sensor
09 Engine coolant temperature sensor
10 Intake air temperature sensor (mass airflow sensor)
12 Throttle position sensor
14 Barometric absolute pressure sensor
15 Heated oxygen sensor (inactivation)
16 EGR function sensor
17 Heated oxygen sensor (inversion)
25 PRC solenoid valve
26 Purge solenoid valve
28 EGR solenoid valve (vacuum)
29 EGR solenoid valve (vent)
34 ISC valve
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Old 01-23-2012, 11:59 PM   #4
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Do me a favor and disregard my previous post. Didn't fully read your answer. I see what your saying about the heater circuit ground.
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Old 01-24-2012, 12:05 AM   #5
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Could you be certain about that joe?
Yes. The schematics are the telling factor.
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Old 01-24-2012, 12:25 AM   #6
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Thanks. I appreciate your knowledge.
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