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Hi JR,
Is it hot there? I know it is here and supposed to get worse next week.
Regarding getting dirty, the checks you need to make on the oxygen sensor are up top where it connects. I'm sure Bentley has something on it. First you want to check heater operation, because it is simple and easy to overlook. The way I do it involves a bit of swift movement. You want to run the car a minute or so, then jump out and read the resistance of the heater by disconnecting and probing the plug with the two white leads heading under the car.
Your objective is to see the resistance begin high and fall to a lower value with time - say about a minute - as the power to the heater is removed. Be swift or practice once to have things ready and you'll verify a good heater by seeing that resistance drop from say 15-30 ohms to about 4 or so if I recall - the numbers don't matter; either it does or it doesn't.
If it doesn't - check fuse 4, and then voltage at the connector you disconnected. Of course, if the resistance is infinite, the sensor or its leads are suspect.
Heater operation confirmed, you'll want to start the car and monitor the voltage on the single wire plug that is the sensor's output. This you do with the plug's rubber boot peeled back and left connected. From a _cold_ start you'll be looking for the voltage to begin around 500mV (1/2V) and after about 20 seconds of engine running, the heater should have it near 600 degrees and actively measuring the oxygen. As that happens you should see the voltage climb to 700, 800, or even 900 mV before swinging back to below 200 or 300.
It _should_ then and thereafter bounce your meter's numbers around back and forth generally from the 200 side (lean) to the 700 side (rich), but the key to operation is the condition sensed by the lambda sond is then read by the ECU which should try to adjust to the opposite mixture, flipping back and forth as it fine tunes the mixture around ideal.
If it doesn't flip back and forth, and I suspect yours won't, it is because either the sensor is not able to report the mixture correctly, or the gross adjustment of mixture is not in the ball park for fine adjustment because of another mixture affecting fault, i.e. vacuum leak, fuel regulator, pump not getting full voltage because of a lousy fuel pump relay circuit board, etc. and on and on. But you first have to find out what the sensor thinks is going on by doing the voltage measurement. The ECU expects the sensor to be delivering valid information after it sees several of these stoich crossings with heated sensors. There are too many possibilities for various readings to go into the "what ifs" at length, so get the readings and post back.
Sorry to say, the resistance measurement Bentley offers has never, to my knowledge, confirmed a bad -016 AMM, and absolutely cannot confirm it is good. That's not to say a number of folks haven't read 4.1 ohms with their digital multimeters and needlessly ordered up a new AMM because of that Green book procedure copied by Bentley. The very best means of ruling out an AMM failure available to a DIY is substitution. Second best is observing the voltage output at rest (ignition on, engine off), then wafting a bit of air past the wire to note basic operation.
Regarding the crank sensor, I wouldn't even be looking at this for your symptoms. Can you measure rail pressure? I know you said they spritzed pretty good and it has a new regulator. Can you measure ECT voltage? You did say the AMM accordion hose had no rubthrough. Does your AC work? Could the oily film have been a condenser leak?
You gave me an important clue in not answering my question (twice now) as to how you were resetting the codes after viewing them. Apparently you only reset them the one time, and that was inadvertent. The codes will not clear, and the limp-home adaptation will not reset, unless you actively do it. Each time you make a change by swapping a part or whatever, you'll need to reset the ECU and drive it a bit to judge its effectiveness.
Keep cool,
--
Art Benstein near Baltimore
A grenade thrown into a kitchen in France would result in Linoleum Blownapart.
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