Susie's Z

I got the optical sensor on ebay from A guy in California. He bought the the whole AC Delco Opti for a project car,then fell ill and could not complete. On my Ac Delco 1st gen Opti that i recently purchased , the shutter wheel is not tack welded. It lines up on a pressed in pin. It was very easy to remove. Shutter wheel in perfect shape, did not bend or even flex. I just hope it goes back in as easy!

Injuneer

Did you test the old unit for 5V pulses?

Susie's Z

I'm confused, I thought pin B on Icm was the low res pulse. Anyway I got 0 to 5 on B nothing on A

Injuneer

The low res pulse from the Opti goes to the PCM, not to the ICM. The PCM sends a pulse signal to the ICM, based on the timing tables in the program. The PCM cannot send the pulse signal to the ICM without input from the Opti.

When I told you how to check the optical sensor, I was referencing pins A and B on the Opti, not the ICM.

Susie's Z

I think I got it ,the low res pulse to the Icm is from the Pcm not the opti. And this test should be done at the opti harness at the opti or at the connector hooked to the intake?

Injuneer

The PCM gets a low resolution pulse from the Opti. It is a variable length pulse, which allows the PCM to determine which cylinder is approaching TDC. Based on the timing tables, the PCM sends a SINGLE, fixed length pulse to the ICM to tell it to fire the coil at the correct time. The PCM is not passing through the low res pulse signal. It is using the low res signal to calculate when to fire the coil. It is just coincidental that the pulse signal is switching 0-5V.

Correct... the purpose of the gray connector on the bracket on the passenger side of the intake manifold is for testing the power supply to the Opti, and the pulse signals being sent to the PCM.

shoebox

...and the best way to look at the low and high res pulses is with an oscilloscope.

Injuneer

If I read this correctly you recently purchased a new AC Delco Opti, and now you are concerned that the optical sensor has failed? How many miles on the new Opti? Was it still in warranty? Of course the newer ones are factory sealed, and opening them voids the warranty, so I guess it's a moot point.

And you bought the new sensor from someone who decided to "part out" a brand new AC Delco Opti?

Susie's Z

That is correct Fred, but could not warranty, because i pulled it apart,which broke the factory seal and is probably the reason water got in ( from the small pin hole leak i later found on the small hose of the Y hose right where it connects above the Opti) and that would probably be what ruined the Opti. My $$$$ Bad. And I didnt just get the Opti sensor, I got the whole unit from him minus the rotor and cap. So I dont even have to re install the shutter wheel and all I have to do is put my rotor and cap on.
And you can rest assure I WILL make sure this one is sealed properly. I can't Thank You guys enough for your expertise on this car. I really appreciate all of you sharing your knowledge with me.

Chimera96

if it has not been mentioned yet, use loc-tite on the rotor screws when you put your rotor/cap on the opti you purchased

AdsoYo

If you're interested, I went 24x and have a leftover optical sensor out of a Delphi opti. PM me if interested, cheaper than buying a whole new opti and it's a genuine Mitsubishi sensor. I can send pics, too. Really want this thing gone.

Susie's Z

I used loctite on all screws in the distributor. I also sealed the entire opti with red high temp RTV, the bottom plastic plate ,metal plate the goes on before the rotor and the distributor cap all have been sealed. Just installed , The Z started right up ! Now I have to repair all nicked wires and deteriorated vacuum hoses I found while searching for this problem. Thank You to everyone who has given their input ! The Z rides Again !