1993 XJS Code FF23

My check engine light comes on and this code appears. The car is running very rich. Upon starting, fuel is blown out the exhaust. Good thing I don’t smoke, the neighborhood would burst into flames after I start the car. Many fixes have been attempted. EGR valve, alternator, O2 sensor, etc. Car can be made to pass emissions so I’ve been told the cats are good. I’m suspecting fuel pressure regulator. Any other thoughts?
Love this kitty!
Thank you!

So this is the AJ6 motor then?
FF23 is an uncommon fault, so not much advice out there …(as I’ve found out being another person with the same fault!)

So, from the engine management .pdf, FF23 is the o2 sensor reporting rich mixture.

possible faults

  1. high fuel pressure
  2. o2 sensor heater ground loose or engine ground loose
  3. ECM ground loose or corroded
  4. purge valve stuck open
  5. High resistance in MAF connector <my vote
  6. Incorrect MAF calibration
  7. Vacuum leak in intake
  8. defective o2 sensor

Clean and tighten the the pin connectors at the MAF and all the other sensor plugs in the intake. Make sure the connection at the temperature sensor is clean and tight too. Disconnect the battery to clear the code and see if the fault returns.

It was the dirty connections that flagged it on my car (after I replaced the o2 sensor/FPR/purge valve of course …:confused: )

Yes. Thank you so much! Some of these have been looked at, but there is a lot of new material here. Thanks for your time and I’ll let you know how it is going!