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

 

"C" is the ground. It has a short black wire that attaches to the stud on the driver side head. Use the stud as the ground for the tests. Verify the black wire continuity by measuring ohms from pin "C" to the stud. Should be close to 0.

"D" being so low may indicate a problem with the coli primary.

If you have the 1-4 volt AC signal on the white wire to pin "B", you have the signals from the Opti that the PCM requires to run the engine.

As a secondary check, while cranking the engine, does the tach needle move upwards a couple hundred RPM? That also verifies the low res pulse signal from the Opti.

 

Thank you.
I appreciate you clearing up the "C" wire and yes I have continuity from the connector to the stud.

D" being so low may indicate a problem with the coli primary.
What is the coil primary? The coil itself?

 

The “coil” actually as two wire coil windings inside. The “primary” coil operates at 12 volts. The “secondary” coil has a lot more windings, and converts the 12 volts in the primary coil to up to 15-20,000 volts required to fire the spark plug. When the primary coil is energized, the voltage builds in the secondary coil, and when the 12 volt power to the primary coil is turned off by the ICM, the high voltage in the secondary coil is applied to whichever spark plug the distributor rotor is pointing to.

If you are using Shoebox's diagram for the 1996/97 ignition, key on, check to see if you have 12 volts at both coil terminals “C1” and “C2”.

http://shbox.com/1/1996_ec_03_ign_system.jpg

 

Thank you I'll take a look. Your knowledge is incredible and I appreciate every post.

 

I have 12v at the coil wires going into the coil.

Why is there 3 pins in the coil and only 2 wires on the coil connector?

 

You have 12 volts at the coil, pin "B" = "C1" (per the wiring diagram) where the dark green wire attaches, but you only had 4-5 volts at pin "D of the ICM, where the green wire attaches. Is that correct? Because it doesn't sound right.

I have no idea why there's an extra pin on the coil.... maybe in some applications, they use that pin for the tach feed.

 

I checked again. A-11.28v D- nothing is reading.
Ignition fuse under the hood is good PCM ignition fuse on the dashboard is good.

 

If you have 12 volts on one end of the dark green wire, and 0 volts on the other end, the wire or the connector pins are damaged. Are you sure you are reading the pins letters correctly on the ICM connector?

 

ICM
pink - A. this is where I’m getting the volts
white - B
black - C (negative)
green - D No volts

coil
pink +
green -
around 12 volts and tested with test light.

 

Both connectors off the coil and ICM, check the continuity of the dark green wire from connector to connector.

 

Continuity between the green from the ICM to the coil good and also between the pink wires.

 

Well, I can’t think of any possible way you can have 12 volts on one end of the green wire, 0 volts on the other end of the green wire, but no issues with continuity on the green wire. I'm at a total loss.

 

If you’re at a loss then I’m totally f#cked. Lol.
I took a video of what I was checking but it won’t let me upload it from my phone.
Your right if I continuity through the green. But isn’t the green the negative for the coil? That should be sending volts back to the ICM?

 

Shoebox's procedure is right out of the factory service manual. The 96 manual (same as 97) logic diagram for the ICM/coil system (Vol 2, Part 1, page 6E-836 to 839, STEP 5 indicates:

1 - Turn the ignition off

2 - Disconnect the ICM connector (are you possibly leaving it connected?)

3 - Turn the ignition on.

4 - Using a DVM, measure the voltage at the harness terminals "A" and "D" to ground.

Do both terminals measure less than the specified value (Value - 10.0 V)?

If not (you only have a problem on "D"), Go to STEP 6.

STEP 6 - Is there only one terminal below the specified value? If YES, go to step 23

STEP 23

1- Inspect the circuit that was less than 10.0 volts for an open or for a grounded circuit.

2 - If circuit is open or grounded, repair it.

Was an open or grounded circuit found? If NO go to STEP 24.

STEP 24 - Replace the ignition coil

If you are sure you have done all the tests correctly, go to STEP 24. Not sure what other choice you have.But you have to be sure you followed the instructions and measured correctly.