LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Confused on O2 sensors on OBDII LT1 Z28

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Old 03-24-2013, 06:26 AM
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Default Confused on O2 sensors on OBDII LT1 Z28

Can anyone tell me what O2 sensors I need for my car.

1996 Z28 with OBDII.

I have long tubes and had the after cat O2 sensor(s) tuned out.

Currently I have a square connector on the drivers side and flat connector on the passenger side.....I have a feeling this is incorrect.

I have plugs in the unused locations.

Can anyone clear this up?


Thanks!
Old 03-24-2013, 07:35 AM
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You should have 2 flat 4 pin connectors for front. Sensor GM #19178930. I just bought 2 of these from GMpartsdirect I think they were around $80 shipped..
Old 03-24-2013, 07:42 AM
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How many flat, and how many square connectors does the harness have?

I can only find 3

Thanks for the help!!
Old 03-24-2013, 07:53 AM
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Well you need to find 2 flat four pins for the front. If rears are deleted I wouldnt worry about those. But the rear sensors are square 4 pin
Old 03-24-2013, 08:43 AM
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Ok sounds like I need to find my missing plug and get the o2 swapped around.

Do you know if the drivers o2 flat wire gets strung across the trans from the passenger side?
Old 03-24-2013, 09:23 AM
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Look near the oil filter for the drivers side flat 4 pin connector.

My car is apart right now so I can't go look and see exactly where it is, but for some reason if I remember correctly I am thinking that when I installed my o2 sensor harness extension that it was done from the top and then pulled down toward the header collector.

You do have the extensions right?
Old 03-24-2013, 10:37 AM
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Originally Posted by nascarnate326
Ok sounds like I need to find my missing plug and get the o2 swapped around.

Do you know if the drivers o2 flat wire gets strung across the trans from the passenger side?
i believe it comes across the motor or in the back there and is on the same run as like the egr sensor plug

http://shbox.com/1/harness.htm

yeah it should be above the low oil level sensor there.
Old 03-24-2013, 11:40 AM
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Most of shbox pictures are for an obd1 car, I have different plugs than the picture shows.

Would the plug be on top of my turns basically ?

Can't fine it at all but I can fine the two square plugs and one flat one without problem. Grrrerrr
Old 03-24-2013, 11:51 AM
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The flat ones for the front should come out of the harness just like my 95 harness pic.
Old 03-24-2013, 04:32 PM
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Thank you for helping me, I found them. Looks like it got wrapped inside of the reloom job someone did...meaning I havnt had functioning O2 sensor for quite some time.

Ordered an extension to work with my long tubes.

For anyone in the future finding this on google

94-95 cars have two flat o2 connectors, one on each side that are heated.
96-97 cars have two flat o2 connectors, one on each side that are heated in the front, as well as two square plugs that are heated in the back, these are like the 98-02 cars.

Last edited by nascarnate326; 03-24-2013 at 08:29 PM. Reason: fixed for future reference
Old 03-24-2013, 04:59 PM
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You got some bad information. 93s are the only non-heated O2 cars (f-body). All other year O2s front and rear are heated.

This is on my website:

Originally Posted by shbox.com
1993 LT1 f-body cars have two 1 wire, non-heated O2 sensors. 1994-1997 have two 4 wire, heated O2 sensors (with 1996-97 cars having two additional rear (post cat) O2s to comply with OBD-II). On the f-body, front O2s use a flat connector. When rear O2s are present, they use a square connector.

Last edited by shbox; 03-24-2013 at 05:06 PM.
Old 03-24-2013, 08:30 PM
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Originally Posted by shbox
You got some bad information. 93s are the only non-heated O2 cars (f-body). All other year O2s front and rear are heated.

This is on my website:
fixed it, thank you. Your site has been insanely helpful for my build.



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