$EE Cylinder ID

[kur4o]

The number represent degrees between low resolution falling and rising edge.
It follows engine firing order. It is used for opti diagnostics.
If you look at an optispark wheel you will get a better understanding.

Frame lost is huge here.
At idle you need at least 50 frames per second and 400 fps at 6000 rpm.
Only direct memory access can provide that resolution, or a factory GM debug tool.

[Terminal_Crazy]

The number represent degrees between low resolution falling and rising edge.
It follows engine firing order. It is used for opti diagnostics.
If you look at an optispark wheel you will get fa better understanding.

Ok, haven’t got one to hand but presumably the leading edge of the large low res slots are 90^h^h. 45 degrees apart on the wheel so 90 crank degrees apart
And the width of the slot in degrees determines the cylinder.
Are the 4 8x slots the same width then? To distinguish these 4 cylinders.

_IF_ that’s so, why have I got 10 different values in the log?
I was going to say “timing error” but don’t we have the high res signal for that?

Frame lost is huge here.
At idle you need at least 50 frames per second and 400 fps at 6000 rpm.
Only direct memory access can provide that resolution, or a factory GM debug tool.

That's my Point.
Without any reference to a preceding frame, Can I tell which cylinder i’m Looking at?

Apologies. Not being an arse, just trying to understand it.
Thanks
Mitch

[kur4o]

To identify the same width cylinder you will need to know the previous one`s id.
Second digit can vary +-2 degree from midpoint or x4-x8. Midpoint is x6
Actually this number is high resolution counts, but I guess PCM don`t count that fast at rapid rpm change. Or there are some built in tolerance protection for pcm to through fake code.

By monitoring these cyl id you can identify bad opti signal.

[steveo]

By monitoring these cyl id you can identify bad opti signal.

can you show me what a good log vs a bad log would look like? ... eehack could do this with an algorithm

[kur4o]

Good data will be if all cyl id show 46,56,66,76,86 or 6 for second digit.

Anything between 5-7 for second digit will be acceptable.
Constant 4 or 8 for second digit will be red light.
I guess lower than 4 and higher than 8 will mean opti fail in a short time.

[Terminal_Crazy]

Evenin'
Just viewed these online of the opti disc and an interesting piece on CamaroZ28.com by GaryDoug on the opti.

The small slots relate to cylinders 1,4,6,7 so would these not be distinguished by the four 8x's ?
and the varying slots as cylinders 2,3,5 and 8?

I still can't decode half of the CylinderId's from the log then as I'm unlikely to ever see the preceeding Id.

Streveo: the last couple of logs I've looked at only had x6 or x7 (and 1 x5) but these were only at idle.

Thanks
Mitch