[Damon88]

Need some help with my AFR readings. Here is my engine set up.

1983 911sc 3.0 with Lambda, SSi's and sports muffler. Running 93 octane, All fuel pressure tests are in spec. Currently running Oxygen sensor unplugged and using Wideband Ox sensor. Waiting to see welder next week to have second bung installed on passenger side SSi.

I just installed a PE Wideband and took the car out for a drive. Having some lean issues between 5000 and 6000rpm. Here are the numbers.

Outside temp were 68

Warm idle was around 12.4 AFR (idle set 950rpm)

3rd gear cruising at 4000 rpm 13.8 AFR

3rd gear between 4000 to 5000 it starts jumping around 17.0 AFR then starts dropping once speed is reached. ( AFR numbers are fluctuating quickly )

3rd gear at 6000 RPM to WOT it goes back to roughly 13.2 / 13.8 AFR.

There seems to be this jump to 16.5 to 17.1 when ever I accelerate hard in any gear, then goes back down once RPMS settle and back to cruising. On decelerating I see it go down around 12.9 AFR.


All vacuum lines and hoses are new. When I remove oil cap idle drops.

Any help with some info on this would be greatly appreciated. Cheers