Hood_Lum

After changing out the optispark and replacing the optispark wire harness that goes over the passenger side I've been getting intermitten misfires.
The car feels like either the spark or the fuels been cut off and the SES light comes on.

I did a search and someone mentioned it could be a bad coil for code 42. Could a bad coil possibly be throwing all 3 codes?

code 16 lo-res failure
code 36 hi-res failure
code 42 EST grounded

I'm currently running a OBD I pcm but I could swap back to the original OBD II if it will help me pinpoint my problems better.



Thanks

Guest47904

What was wrong before changing the opti and harness?

Unplug the white wire from the ICM and PCM and ohm it to ground while moving it around.

Check 12 volts from the pink/black wire to the red wire at the opti. Then confirm 5 volts at the purple/white wire PCM black connector pin 20 and at the red/black wire PCM black connector pin 2. When measured in reference to the pink/black wire PCM black connector pin 3.

Injuneer

DTC 16 and 36 are caused by the Opti, not the coil. If its running, even badly, DTC 16 is a "stored" code. Did you clear the codes after replacing the Opti?

Hood_Lum

The car used to die after 10 mins of driving. Here's the thread:

https://www.camaroz28.com/forums/sho...d.php?t=692155

The code 49 was because I the MAF was unplugged when I did a test start after the opti was replaced.

Which reminds me, the opti didn't go in smoothly this time. I had a hard time finding the slot. Then it slid right in and it was flush. I assumed it was in the slot but now I'm starting to worry maybe it's sitting loose on one of the 3 big circles. So if it's constantly spinning the opti in one direction it's fine but if it slows down then the play with the dowel sitting in the big circle will give it false reading won't it? Hence the code 16 and the feeling like it's about to die but if I give it some gas it comes back on.

[EDIT]
Haven't had a time to run any test on the car today but I will as soon as I get a chance.
All the codes were cleared after opti install.
Code 49 was cleared afterward as well.

Injuneer

If its turning, right speed or wrong speed, smoothly or irregularly, its going to put out the high and low res pulses. Since the PCM just counts the pulses, its going to get a count, and assume its working correctly. A "slipping" Opti would not set a code. Engine wouldn't run, but wouldn't set the DTC 16 or 36 codes. And there's no way for the Opti to "slip" or have "play" in it. If the dowel pin wasn't in one of the three small holes, it would be pressed hard against the back of the Opti. Even if it managed to "float" in the clover-leaf "hole", it would still be turning and putting out the signals.

Where did "code 49" come from? First time you mentioned it, and there is no DTC 49 that I've ever seen listed. If you meant to type "42", that has nothing to do with the MAF sensor or unplugging it. That would be DTC 48.

Hood_Lum

I must've meant 48.
That code never came back after I cleared it.

Guest47904

Fred, I told this "guy" about the problem with the opti feed back signals and the IC back in June. See here https://www.camaroz28.com/forums/sho...72#post6000072

It's now November and he still hasn't done anything other than throw parts at the problem.

I'm out a here.

Hood_Lum

Sorry Speedy, I do value your advice and I did take measurements.
Before swapping out the opti I did all the measurements laid out in the 96 Camaro Service Manual. All the measurements from the distributer harness came back correct. So according to the manual the opti was the likely suspect. After changing out the opti my issue with the car dying and not starting up again was gone.

Now the problem is it will misfire or something is off with the timing.
I unplugged the connector going to the ICM and stuck one end of the meter to the white wire and the other end to ground. I moved the white wire around and still have good continuity.

Measuring the pink/black wire to the red wire coming from the opti I got nothing.
Measuring the pink/black wire to the red wire going to the opti I got 12 volts.
This is with the key in the on position and not cranking.

Using a meter and touching pin 3 to pin 2 I have no voltage.
Using a meter and touching pin 3 to pin 20 I have no voltage.
This is with the key in the on position and not cranking.

I've had a similar problem before where the car would run fine then die out and run fine after a difficult restart. That time it turned out to be bad bearings in the opti.