Ok on my 3rd opti this summer, the latest I put in I took the old sensor from my original opti and this time it won't even get spark.
I have talked to may people and have been given some advise, some believe that I am wasting my time changing out the opti's and being the third one I've been told that it isn't my issue. But after changing ever one out the car fires and runs. The first was a month the second only a day. This one no spark, but I did changed the sensor. The bearing in my original opti looked bad and the disc was spinning lop sided so there is aa chance that it ruined the sensor, but I took that risk.If it isn't the opti going bad then why would the car fire up after I change them.
So I did the tests and here is my results. Note the battery in the car isn't the strongest (because of all my trying to start it).
Check for dc voltage with a digital meter at harness terminal "A" to ground and and also "D" to ground.*Note:*Use a modern digital meter with at least 10 megohm impedance to protect the PCM (in case you measure anything in that direction). Do not use a test light for looking at voltage potentials from electronics! Also make sure your meter leads make good contact and are clean and tight. Check that you get a zero ohms reading by touching the two leads together. If it is not zero, merely adjust the readings you take by the skew. That will ensure accurate resistance readings. On "A' i had a reading of over 10 volts and on "D" I was around 4-5 volts.
*Result should be 10v dc or more on the A and D terminals. If you get no voltage, use the diagram and chase back toward the coil and the ignition fuse. Power for the ICM comes from the ignition fuse and through the coil, so any of that could be bad.
If you have good voltage, switch the meter to*ac scale*and connect test leads to terminal "B" and to ground. Observe meter while cranking the engine. You should see between 1 and 4 volts ac (those are the pulses that trigger the coil to fire).On "B" while cranking the engine I was getting between 2-4 volts.
I might be missing ssomething, but I didn't really understand "to Ground" I had the negative of the multi meter grounded out on the car. My buddy thought that "C" might have been ground, but looking at the wiring diagram that looked like it was power, but the instructions from shoebox only said to*You should also check "C" of the ICM harness for continuity to ground.I put the volt meter on the "C" and the negative to ground on the car and had continuity that way.*
So I am not 100% positive if I followed these instructions correctly or not. I am challenged on multi meters but am trying to learn. I find it easier to change the opti out than read a meter. LOL