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I use my trusty 7/8 inch box end wrench.

slip the wires througn the center of the wrench and use the box end to open, you can even use a second wrench on the open end for more leverage.

Ok, just tried to get this ****in' O2 sensor off with a oxygen sensor socket and it just won't come the **** off. I have never seen anything so ****in' seized up...

Originally posted by Quick Sliver:
Ok, just tried to get this ****in' O2 sensor off with a oxygen sensor socket and it just won't come the **** off. I have never seen anything so ****in' seized up...

Time to get out the Dremel...

i managed to get the front o2 sensor off, used a rachet with a 7/8 crow's foot attachment and a 2 foot breaker bar. but now the rear one is stuck and i barely have any room to work with.

Originally posted by curtklze:
I use my trusty 7/8 inch box end wrench.

slip the wires througn the center of the wrench and use the box end to open, you can even use a second wrench on the open end for more leverage.

Try it, it really does work. Maybe spray a little wd-40 ahead of time as well.

I was having trouble too. I used a 7/8" box end wrench borrowed from autozone after spraying some lubricator. Hard but worked.

Originally posted by RayRay:
quick question... i just bought some ntk universal o2 sensors and i need to know wat colors to match up to the old wiring.

NTK's - 2 black, 1 white, 1 grey
front oem wires - 2 black, 1 white, 1 blue

the black ones are a no-brainer, but i just wanted to make sure with the other two before i hooked up the wrong wires.

I just picked up some NTK's and mine are 2 whites, 1 black, 1 grey

it gives me a little picture of where all the wires should be on the connector and what color they are but I just want to be sure before I start splicing up the wires. which wires are which on the OEM harness?

blue= signal?
white= ground?
black= heater?
black= heater?

I've checked my shop manual but unfortunately I dont have the wiring diagrams, if someone does have one can you please help.

Originally posted by johnnyb:
I just picked up some NTK's and mine are 2 whites, 1 black, 1 grey

it gives me a little picture of where all the wires should be on the connector and what color they are but I just want to be sure before I start splicing up the wires. which wires are which on the OEM harness?

blue= signal?
white= ground?
black= heater?
black= heater?

I've checked my shop manual but unfortunately I dont have the wiring diagrams, if someone does have one can you please help.

I typed the wrong colors in my post, its 2 white, 1 black, 1 blue on the NTK's. And I never got a picture diagram with mine, can you scan yours?

I already installed one of NTK's but I'm getting a CEL code 15 - inactivation LH02. Not sure what is wrong. Any ideas?

I just found this link...

http://www.ngksparkplugs.com/techinfo/oxygen_sensors/installation.asp?nav=32200&country=US

Case Number Two
4-Wire Oxygen Sensor
OLD NTK
Blue Black
White Gray
2 Black 2 White

Wiring Diagram for US model'94 MX-3 1.8 litre, from the Mitchell repair manual:

BLK - Heater Ground
BLK/BLU - Signal Ground
WHI/RED - Heater Supply
RED/BLU - Signal (Left Sensor)
WHITE - Signal (Right Sensor)

From the '91 Mazda Workshop Manual

BLK - Heater Ground
BLK/BROWN - Signal Return to ECU
WHI/RED - Heater Supply
RED/BLU - Signal (Left Sensor)
WHITE - Signal (Right Sensor)

<small>[ May 15, 2004, 03:03 AM: Message edited by: IanL ]</small>