juiSSed1172

I was told the other night that tapping into the PCM for the AF gauge hookup doesn't work correctly on LS1s (Or maybe it was 98's only)

He said that if you splice the o2 signal wires to the PCM, you will throw a SES light for that o2, and the gauge still won't pick up the signal. He claimed that the only way to do it correctly was to grab the signal from the purple wire on the o2 before it hits any harnesses.


I shrugged it off as BS, and tapped
47
PPL/WHT
HO2S Signal High Bank 1 Sensor 1

The AF gauge did NOT get any signal after the car warmed up, and then it threw an SES light for Bank 1 Sensor 1.

What the hell is up with this? I've seen a few ls1 cars that tapped into the EXACT same signal wire for their gauge, and it works fine. (Diff pinout, same wire function for later cars)

Any ideas?

TA TED

The input buffer circuitry of your A/F guage is slightly loading down the o2 sensors output and the PCM isn't seeing the full voltage range. Therefore the PCM thinks you're running lean. Try a different manufacturers guage. I was using a good Nordskog guage that measured in the decimal format (.87). I had to switch to a Summit dancing bargraph type that is not nearly as accurate. The Summit guage doesn't load the system and all is fine. Good luck.

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juiSSed1172

I'm using the generic summit bar gauge.


The gauge worked perfectly in my GTA, which is odd.


I'm going to pull the pcm out and check the grommet tomorrow.. I'm thinking that the wire got pinched and was shorting out on the body when it was tapped into the o2 feed from the PCM.

Hopefully that is all that the issue is.

Kobwo

What was the outcome?