24>58 reluctor hack??

[Bruce Melton]

Seems the only internal problem with fittting a 06 LS2 or LS7 into a 97>2005 is that the reluctor is 58 tooth vs everything else being 24. The sensors are a wiring fix but isn't there a way to "hack" the 2x reluctor using our Flashscan?
The alternative is to tear the engine apart and change the wheel.

[GMPX]

It embedded way to deep in the code in the PCM, so it's bascially a no can do.

Cheers,
Ross

[Brains]

Does the main CPU loop itself count the pulses, or is that handled by other hardware?

[GMPX]

Other :-( , the one just below the Flash Chip.

[Bruce Melton]

Other :-( , the one just below the Flash Chip.

You could make some people very happy if you guys could get this. Far be it from me.

[GMPX]

Will never happen sorry, it is non configurable.

[Bruce Melton]

Will never happen sorry, it is non configurable.
My faith is destroyed. Thanks anyway!

[PSWired]

Sounds like a job for some external circuitry...

[Bruce Melton]

Yes, a divide by two device. 58/~2= output. I suppose it has to be really quick however. The alternative is to tear down a brand new, under warranty, LS7 to change out reluctor.

[dfe1]

58/2=29. How do you get from 29 to 24?

[Bruce Melton]

Originally Posted by Gary Z
If it is true that the LS7 uses the Electromotive-type 60-2 timing wheel, then it should be fairly straightforward to generate the 24x signal required by the Gen III PCM. The signal generated by the Gen III reluctor wheel needs a reference every 3 degrees of crankshaft rotation. This reference could come from a frequency doubler phase-locked to the 60-2 timing wheel. Once you have the reference signal, it can be used to clock a shift-register that is loaded with the 24x code sequence once per revolution.

-Gary

This all funny math to me from a thread:

http://www.ls1tech.com/forums/showthread.php?t=345645&page=2&pp=20

[GMPX]

I have not seen the LS7 crank pattern yet, but the LS1 is not just simple evenly spaced pulses, it is quite a complex waveform with various combinations if long/short pulses to indicate where it is (rotation).

Cheers,
Ross

[Bruce Melton]

http://home.new.rr.com/meltn/reluctr.jpg

[GMPX]

Got an LS1 shot also?

[Bruce Melton]

LS1
http://home.new.rr.com/meltn/1reluct.jpg

[joecar]

Make up a reluctor wheel (with the correct notch 'waveform') which mounts on the crank pulley/balancer and have the CK sensor mounted next to it (plug the original CK sesnor bore).

[GMPX]

:exactly:

Just look at the differences between them, the small / large notch on the LS1 wheel creates that complex pattern, the LS2 is more along the Bosch lines of thinking, they have always used that type of arrangement.

BTW, anyone got a Duramax crank in the garage?

Cheers,
Ross

[PSWired]

Whoops, had forgotten the crank reluctor had that pulse encoding pattern on it. This idea:

If it is true that the LS7 uses the Electromotive-type 60-2 timing wheel, then it should be fairly straightforward to generate the 24x signal required by the Gen III PCM. The signal generated by the Gen III reluctor wheel needs a reference every 3 degrees of crankshaft rotation. This reference could come from a frequency doubler phase-locked to the 60-2 timing wheel. Once you have the reference signal, it can be used to clock a shift-register that is loaded with the 24x code sequence once per revolution.

Seems like a good solution, but the Gen III PCM uses that pulse-encoded pattern to determine the absolute crankshaft position at startup. The circuitry would need some sort of input to determine when to start the encoded sequence. I suppose this position information could be gathered from the camshaft position sensor, but the circuitry to implement that would get very complicated in a hurry.

Sounds like the mechanical solution to this problem might be the easiest one...