also posted in 2nd gen forum...

I just installed a new PLX SM-AFR unit with a SM-AFR gauge, and get weird readings!

The sensor is intalled about 24” away from the engine per PLX recommendations. This is a 90 RX-7 with long headers, no cats. The sensor is in the header, so it’s reading only one rotor, front I think. I have true dual exhaust, no opportunity to read both rotors together.

At startup, idle, cruising: the afr readings rapidly oscillate 19-20-Lean or Air.

Full throttle at low revs reads around 17

Full throttle higher revs it goes to 13-14

No way is this right, the car runs rich esp at idle and low revs, can smell the gas. Pugs are fresh and clean, motor runs great, not like one rotor is getting no gas or something.

Any ideas what’s going on? Any feedback would be appreciated. Thanks!

 

19 to 20 at idle with out any kind of fuel controller is normal.
if you do not have a piggy back or something, 17 AFR at full throttle and low rpms is normal ( N/A ) because your putting the engine under a heavy load. feeding a bunch of air at a low rpm. then, when the engine gets going and builds up your rpms the fuel catches up (secondaries) giving you the air fuel ratio you have. if your car is N/A this is ok (13-14). but if your car is the turbo model, then you will have to get some kinda fuel controller and bigger injectors. 17 AFR for a turbo model is WAY TOO LEAN!
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