OK, sure I am VERY Grateful for SOME here who can use their minds.
GM engineers REQUIRED my 60-2 (GM-58X) Target Wheel accuracy for OBD-II LAWS.
Thus, ALL THOSE "misfire/rough running/bad Idle/ etc.) thread solutions needed CAN BE FOUND by "reading" TW tooth Acceleration.
I can explain if asked.
Lance

 

I would like to hear more about this. What do you use for measuring tone wheel acceleration? Presumably an oscilloscope? What 'problems' do you look to solve with this also?

I know very little about requirements of meeting OBD laws, but do the OE's have to be able to identify specific cylinders for misfire counters, hence the higher tooth count (and accuracy) is required? Was this not achievable with the old 24x reluctor? 24x means 24 teeth per revolution of the engine, or 6 teeth per cylinder (based on 4 cylinders firing per revolution), are the ECU's not able to accurately pick individual cylinders with this resolution?

Thanks.

 

Judging by the misfire-detection tables in the 2004 Corvette, they were able to do per-cylinder misfire detection up to about 3000 RPM, and they switch to "per revolution" misfire detection for 3000-6000, and no detection above that.

I assume that the number of teeth was a limiting factor. That, and / or the amount of computing power that was available at the time. The signal from a 52x reluctor might just be a blur to the Gen-III PCMs.

 

My work was to measure the time of the space between each of the 58 teeth and know WHERE the -2 tooth location was on the crankshaft.
Thus NOT event derived as GM, Motec, etc.
Yes, I made my own processor, more powerful than the Intel 8086 released that year.
The empty location on the Target Wheel is measured twelve times, which is necessary for accurate acceleration measurement.
That allows me to know the location, in degrees, when the combustion starts AND the quality of the combustion.
More questions ?

 

How do you determine the quality of combustion? Just by the variance in timing of the individual tooth counts?

 

Yes, I will add that when I sit in the car with a "running" engine I can feel how well the engine operates.
I do believe that direction may be in the opposite rotation down under ?

 

Lance, isn't this what is being done when you perform a "crankshaft variation learn" on a scan tool? Basically letting the PCM relearn the position of the reluctor wheel?