Right, so I've bought my AFR gauge and kit which will be here next week hopefully. What reading am I looking for? 14.7 at idle I take it? And the ECU should do the rest at WOT and part throttle?
Somewhere in that region. The AFR meter will show up wobbles caused by the Air Flow Meter wiper wearing its tracks, or Thermotime switches failing to run the 5th injector properly. Or any vacuum leaks as they happen. Generally as you accelerate the mixture should go richer , then lean out again to higher than 14.7 as you reach cruise. Not many people fit wideband sensors alongside stock FI, so your path will be one of learning 'normal' so you can spot faults. Carburettor people like me see 11 choke on, 12-13 flooring it, 14-15 idle 16-17 cruise, 20 engine braking (emissions conscious FI shouldnt go that lean on a bus as thats NOx rich) Some people with performance engines end up with idling at lower figures. More modern engines go towards leaner but have a catalyst to get rid of NOx and are designed not to melt and crack ..
