BLACK SMOKE (RICH) ON ACCELERATION-930
#1
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I've had this before on other 911 Turbo's with different fixes. This one is very defiant in repair. Have switched O2 parts (cntrl unit and relays). When I disconnect the freq valve, excessive richness disappears. O2 sensor is working. It only occurs on light acceleration at lower RPM's-see black smoke from exhause in mirror and engine hesitates for a few seconds then clears out as RPM goes up-anyone have this happen?