Thanks Doug. I was hoping you might chime in.
You introduced injectors into the mix, which I didn't comprehend.
I'm here to help - plus I gotta get my post count over 4K so I can be an expert in something
Ok, seriously -- I introduced injectors into the mix because they are the other half of the air/fuel mixture. Malfunctioning MAF's are a clear issue, and clearly the ECU can cause an issue with fuel if it
is malfunctioning, but what if the ECU is ok and is just getting bad information about the amount of fuel being dispensed (much like the amount of air entering the engine with a bad MAF). It seems to me that a malfunctioning injector (perhaps that isn't the correct part - I'll check with some friends who are a bit more knowledgeable) could have the same effect as the MAF but from the other side.
Fortunately, clogged injectors seem to be an rather uncommon issue for us, presumably because most of us use good gas.
True, but clogged is not the same as malfunctioning
So let's look at two injector scenarios: underperforming (partially clogged) or 'dead' (fully occluded or some other mechanical malady).
I'm guessing a single under-performing injector may not impact the O2 signal too much. It might take multiple under-performing units to trip an adaptation code. What do you think? Any other codes come to mind that might point to this scenario?
I would think one severe malfunction or fully dead injector would trigger the issue - you're talking about a 25% increase in unburned oxygen suddenly making it's way to the O2 sensor.
Now if an injector is 'dead', would we anticipate a cylinder-specific 'misfire' code? Do we know what is behind the cylinder-specific 'fuel injector' codes (03, 04, 05, 1F, 20, 21, 22, 23)?
I don't know for certain, but I would be willing to bet that the misfire codes are not triggered by a sensor measuring actual spark but rather a sensor that measures whether or not the coil discharged (and is therefore recharging as it should). This is pure conjecture on my part, but is based on the fact that I've never seen any sensors inside a cylinder and the only other thing attached to the plug is the coil.
As for the fuel injector codes, I'm afraid I don't have a clue, but I would expect a code for those as well.