Wiring in a 4 wire o2 sensor

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hatchedlsvtec

Large Member
Just finished the lsvtec swap in a 91 civic. ECU throws a code 41 for o2 sensor circuit malfunction. I currently have the stock civic o2 sensor with one wire hooked up, so I assume the obd1 vtec ecu is looking for a 4 wire o2. I have the obd0-obd1 conversion harness in place with supplied wires for this sensor, they are not connected to anything at the moment. I suppose I would need to get a gsr o2 sensor with 4 wires and just hook them up, huh. Confirmation? Info? Thanks
 
You can use any 4 wire o2 sensor.. the universal ones are usually cheaper because they don't have plugs on the end, just bare wires.

Basically you just need to connect the 4 wire sensor to the correct wires on your conversion harness and it should work fine.

If you happened to buy the harness from Rywire they have instructions on how to hook everything up http://www.rywire.com/store/images/instructions/inst_0to1jumper.gif
 
Very nice I appreciate the speedy response! Also, for some reason my fuel pump won't normally turn on, so I had to run a switched hot wire to it... the two main relays I have been swapping I beleive work fine, so any ideas why this could happen?
 
So you're not getting power to the fuel pump from the factory wire right?

Make sure all the grounds in your engine bay are connected properly as some of the ECU grounds are located there. Other than that I'm not sure off the top of my head.. I don't have a wiring diagram handy for your Si.
 
So I got a universal 4 wire o2 sensor and I am pretty confident with how it's wired to the ecu, but after resetting it, It still throws code 41 for o2 sensor circuit. Signal wire goes to d14, heater control from a6 to one of two white wires on o2, a black ground from ecu to ground on o2, and a power wire from ecu to the other white wire. Is this wrong?
 
techlambdastocko2wiring.gif
 
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when wiring the o2 sensor can i just splice the 4 wires to the ecu connectors?
 
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