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AFR guage help

Tre3zy

Well-known member
Joined
Nov 25, 2008
Messages
602
Location
South San Francisco, CA
hey guys i just finish tapping my afr guage to the o2 sensor wire and i double check everything to make sure i did it rite.... but when i turned on my car the guage do work but it only stays all the way to the let which is the "RICH" part and the light doesnt move around like how ive seen in im my other friends galant.... any idea what the problem is? my friend said that my O2 sensor might be shot thats why the guage isnt working properly.... what do you guys think?
 

GVR4_1057

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Sep 3, 2008
Messages
676
Location
Brucetown VA
It is hard to say without seeing where you tapped the wire from. However when the o2 sensors go bad the usually go to the rich side (way rich). Did you use the factory narrowband o2 tap by the ECU? It is green with a white stripe and has a white insulated spade connector on it.
 
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1990ggsxnj

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Nov 21, 2008
Messages
525
Location
Blackwood, NJ
I would see if that friend will let you borrow a good 02 sensor to see. If you let the car run for a while does it start to work a little?
 

O2 sensors rarely go bad where they put out a HIGH voltage, its usually LOW voltage output that is a sign of a bad sensor. It sounds to me like you tapped the wrong wire. The O2 is pin #4, and the wires are numbered looking at the back of the ECU:
click
Check the voltage on the wire with a voltmeter.
 

Tre3zy

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Nov 25, 2008
Messages
602
Location
South San Francisco, CA
ok well i did what exactly they told me to do here

click

it says to tap it from the ECU but when i did that it only stays in RED(lean side) and doesnt move around.... so i tap it in the wire on the o2 sensor it self.... there is 4 wire on that O2 sensor.... 2 white 1 black and 1 gray.... first i tap it on one of the white wire and check it and no power is running on the gauge.... so i tap it in the second white and now it just stays in green ill put up some pictures when i get a chance
 

GVR4_1057

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Sep 3, 2008
Messages
676
Location
Brucetown VA
Use this wire. It is at the ECU.
 

1990ggsxnj

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Nov 21, 2008
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525
Location
Blackwood, NJ
I think you need to make sure you didn't cut the wire completely when you tapped into it after making sure it'st he correct wire. If the ecu is not getting the information than it will run rich which the o2 sensor is still reading.
 

toybreaker

iconoclast
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Apr 30, 2006
Messages
3,581
Quoting GVR4_1057:
Use this wire. It is at the ECU.




^^^This

Quoting 1990ggsxnj:
I think you need to make sure you didn't cut the wire completely when you tapped into it after making sure it'st he correct wire. If the ecu is not getting the information than it will run rich which the o2 sensor is still reading.



^^^And this.

Excellent post! /ubbthreads/images/graemlins/smile.gif
 

Tre3zy

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Joined
Nov 25, 2008
Messages
602
Location
South San Francisco, CA
well i didnt cut the wire completely.... so i dont know whats going on.... althought long even before i put the gauge i notice that my car is running rich.... so yea... i slice the wire cover and tapped the gauge wire.... i didnt cut the ecu wire completely
 

atc250r

Staff member
Joined
Sep 11, 2003
Messages
13,235
Location
Orange County, NY
Did you try connecting it to the wire that GVR4_1057 showed you in his picture? That is the best way to do it since you won't have to splice into anything. Mitsu provides you with a perfect spot to connect that gauge, why not use it?

John
 

Tre3zy

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Joined
Nov 25, 2008
Messages
602
Location
South San Francisco, CA
yea maybe ill try it.... its kinda hard to see it though.... i dont know if i make any sense but if any of you guys have a more pix of that wire it would be nice.... thnx
 

Muskrat

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Joined
Jun 13, 2004
Messages
2,107
Location
Lexington, KY
It's connected to the O2 sensor signal wire (pin 4 on the ECU, white wire). Just follow that back to the crimp connection and you should find it. It's green w/ white stripe.

It may help if you pull the ECU out. Also, it may be wrapped up with the wires. That pic was taken after I had finished rewiring my harness, and I decided to leave that section loose.
 
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1990ggsxnj

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Joined
Nov 21, 2008
Messages
525
Location
Blackwood, NJ
Take the plastic shrouding off around where the passenger's foot would be both by the ecu and by the air vents...just poke around with your hand to the left of the ecu location, about where the passengers right foot would be directly under, but behind the glove box (just push the glove box sides in and let it hang, much easier to get there). It was the only wire hanging by itself when I looked.
 
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As mentioned above, you could try tapping that wire with an actual voltmeter and tell us what the reading is. This way we could make sure you're at least seeing the proper range of voltage (0-1v). Also check the voltage at the sensor and make sure they match. If they match, but it's out of spec, I'd suspect the sensor. If they don't match, well, then you know to keep looking for the proper wire. If the readings match and you see oscillating voltage from 0-1v, then sounds like your gauge is FUBAR.
 
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