Narrowband A/F logic check?

[CRDMS1]

For my narrowband A/F gauge install, I'd like to tap into the first O2 sensor at the exhaust manifold (as opposed to the ECU location). For those who haven't looked...the 4-wire O2 has its own wiring harness which then plugs into a harness running to the ECU. I believe the blue wire attached to the sensor harness corresponds with the pink/blue wire running to the ECU which is the O2 voltage pickup according to other threads.

My logic is this: If something goes haywire, I can replace the sensor/harness instead of the whole wiring to the ECU. Is this a sound plan? Any potential problems?

Peace...(hippy)

 

[MSP Pro]

Possible problem is the O2 sensor can't drive both the ECU and the A/F gauge. Don't know if you can test it any way other than trying it. What do the directions that come with the A/F guage say?

 

[CRDMS1]

Hmmm...I assume the sensor simply uses a very high resistance to read the O2 voltage, but I'll check the documentation. In any case, every A/F gauge I know of taps into the O2 sensor wiring at some point between the sensor and the ECU.

The directions seem to direct tapping into the O2 wire at the ECU location (PIN#60, pink/blue wire on MSP). I've seen folks on this site suggest tapping the wire in the engine bay for simplicity, but I haven't had anyone confirm they did it successfully. I'd rather avoid the hassle of getting to the ECU and save the stock wiring if possible by only tapping into the corresponding wire (blue) at the sensor harness. Anyone?

Peace...(hippy)

 

[perfworks]

you can tap into the pink blue it will send you the same signal. just -t- into it.

 

[CRDMS1]

you can tap into the pink blue it will send you the same signal. just -t- into it.

How about the blue wire on the other side of the plug which connects the O2 sensor to the ECU wiring? This lines up with the pink/blue wire, but I don't know if there are any electronics inside that little plug

Thanks for your reply.

Peace...(hippy)

 

[perfworks]

Thats fine you can use the blue wire also.