OBD-II toothed wheels for crankshaft position sensing

[Stuart Woolford]

> > Why everybodies obsession with external 58 toothed wheels?, you do
> > realise that you already have a 120 odd tooth wheel already bolted to
> > the back of the engine?. (Yes, I do realise you also need a TDC reference)
> 
> A couple of reasons, one is what happens as a tooth gets ground 
> down by the starter. This has happed to a couple of cars that 
> the starter went south on. Also each system would then have to 

the software could (should?) *easily* spot this (even under cranking) and 
warn of this bad situation (which should be fixed for more reasons 
than EFI..) - a bonus??

> maintain a different setting for each tooth count, i.e., Chevy 

again, with a seperate TDC sensor, this could be calibrated on 
first-crank.. (but we all know that, right?)

> (small and large flywheel), fords, dodges, 4 cyls, etc. Lastly, 
> the frequency of interrupts from the flywheel would be 
> around 2 times that of the 58 tooth part (I don't think this 
> would be a big problem however). 

so long as it is allowed for in the design..

> Also if we are using the 58 tooth wheel (really 60) we have a 
> reference location that we can still use even if we lose the TDC 
> reference. I think that electromotive uses this as the basis for 
> their system. I'm not sure what they use for their 'sequential' 
> FI.

now this is useful, but reasonably easy to add to a starter-gear 
system (with a little non-invasive modification)
 
> Just some ramblings ;-)

same here ;)
----------------------------------------------------------------------
Stuart Woolford, stuart at spectel.co.nz

                      >>>>In VI Where Available<<<<
----------------------------------------------------------------------