Oxygen Sensor Wires Backwards?

phutch11

Member
Nov 14, 2005
328
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I've recently completed a 5.0 EFI swap from a 93 into my 66. I went the hard route and adapted the 93 harness to fit into my car. The good news is that the car starts just fine but after about a minute of running well, the idle starts to stumble and then race to catch itself.

I've heard that this may be caused by having the harnesses for the O2 sensors going to the incorrect bank of cylinders. Upon consulting my Hayne's wiring diagram, the diagram only speaks of the sensors as being "Right" or "Left" which is open for debate based on which way you are viewing the engine.

So here's my question: currently my passenger side O2 sensor has the Red/Blk, Gry/Yel, and Blk/Wht wires going to it, with the Gry/Lt Blu, Blk/Wht, and Gry/Yel going to the driver's side sensor. Can anyone confirm if this is correct?

Misc Info - Heads ported, E-cam, No TAB/TAD, No EGR
Codes pulling - 31, 81, 82, 84, 85, 94, 44

Thanks
 
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That is why I always say driver or passenger side when I'm working on a car. That being said I seem to remember "left" and "right" being from the point of view as if you were siting in the driver's seat.

Where did you plug the O2 sensor into the exhaust pipe ? If the distance isn't somewhat close to the stock location I've heard it can cause that exact problem at idle.
 
According to this...(assuming left is the driver's side), then you've got them reversed.

91-93_5.0_EEC_Wiring_Diagram.gif