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Okay to wire A/F Guage straight to the o2 sensor?

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Old 06-07-03, 01:37 AM
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Question Okay to wire A/F Guage straight to the o2 sensor?

I would try and search, but you can't type two letter words like o2 or AF... anyway.. mine is grounded to the chasis, and the other wire connects directly into the o2 sensor wire... and it seems to work, but funky, like shutting off sometimes... so I was wondering if the way I wired it is typical?
Old 06-07-03, 01:39 AM
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i am pretty sure that is how i got mine wired and it works fine
Old 06-07-03, 02:51 AM
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This is a bad idea and a common mistake. The O2 sensor cable has a braided shield wire around it to protect the signal from electrical interference. This shield wire is insulated from the signal wire and is grounded. When you tap into the cable it's very likely you'll end up with the shield wire touching the signal wire. This will ground the O2 sensor's signal and result in neither the A/F gauge or the ECU getting a signal.

The shield ends ~6" from the ECU plug, so you should always tap into the wire at the ECU. You can get power and ground there too.

When you say the signal shuts off sometimes, is that when you lift off the gas? The injectors shut off during deceleration, so the A/F gauge will show nothing. It also won't read properly until the sensor reaches operating temp, which takes a few minutes.
Old 06-07-03, 02:53 AM
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Re: Okay to wire A/F Guage straight to the o2 sensor?

Originally posted by The Truth
mine is grounded to the chasis, and the other wire connects directly into the o2 sensor wire?

ummmmm no.... one should go to switched 12v
Old 06-07-03, 03:11 AM
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Three wires: power, ground and signal.
Old 06-07-03, 05:34 AM
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Make your connections at the ECU for a tidy and correct way. https://www.rx7club.com/forum/showth...ht=a%2Ff+ratio
Old 06-10-03, 01:26 AM
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thanks silver rotor.. that's what I needed to know
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