Installing a cruise control, need to know the frequency of the vehicle speed sensor signal. This is stated in pulses/mile, and will be something like 2000, 4000, 5000, 8000, etc. Could check this with my scope, but fast as this car is I'd run outta extension cord in a hurry! Looked on the tech site, found everyting but.,

TIA

Dan

 

Ya know, I began posting a formula for determining this thing.. but in the end, I think you'll be better off using an oscilliscope to get the VSS Frequency at 60mph and dividing it by 60..

Another possible way (I've never tried it so don't flame me if it doesnt work) is to take the engine RPM at 60mph, divide by 60, then multiply that by the axle ratio.. This 'should' give you the driveshaft's revolution rate, which in theory, should be the VSS Signal speed assuming there is 1 pickup and 1 field source.. if there are several signal sources (several magnets, or a shudder wheel) then you have to divide that by the amount of shudder slots or magnets..

Ya know.. I think I just confused myself.. I hopet his helps and that I'm not COMPLETELY Wrong, though I could be so take this with a grain of salt.. just trying to help..

 

ya know an OBD2 logger may help you with this..

 

I would think the shop manual would provide this type of information, although not necessarily directly. It may say, for instance, that the VSS issues four pulses for every rotation of the front differential.

 

I looked online through the obvious sections of the tech info, no reference to VSS frequency that I was able to find. The oscilloscope's the way to go, but both of mine are AC, so again they're of limited utility in a moving vehicle.

Thanks for the replies.

Dan

 

you could always use a Multimeter with a pulse counter (probe for frequency counter too) some multimeters are compatible with signal generators (Square wave) which means you should be able to use it to measure it..

 

That's not a bad idea. My DMM is pretty old, will measure capacitance and transistor beta, but has no freq counter function. I ended up using the Rostra suggested frequency of 4000 (which after talking to them I gather they suggest for most Japanese cars, so it may or may not be on the money re: the EVO) and the unit functions great.

Dan