914turboford

I have a customized Four Wheel Drive 1975 Volvo Wagon. It is powered by a 1997 Chevy Camaro 3.8 V6 coupled to an older 1986 Chevy S10 automatic transmission. I am also using the 1986 S10 cruise control. I made a custom reluctor ring from a motorcycle sprocket to create pulses for the stock vehicle speed sensor. This sensor sends a signal to the 1997 engine computer which sends a signal to the 1986 cruise control. I have found that the cruise control will only work up to about 35 mph. I assume there is a mismatch in that the cruise probably thinks the car is going too fast and won't engage above 35 mph. I would like to add a frequency divider circuit to cut the frequency in half or fourths. The manual says the 1997 engine computer is supposed to output 4000 pulses per mile which works out to about 66 Hz at 60mph according to my calculations. However, I have measured about 1000 Hz with my DVM while having the wheels jacked up and the speedometer indicating 40 mph. I am supplying this in case the range of the frequency is important to the design of the circuit. I believe the signal I am trying to modify is a square wave going from approximately 0 to 5V+. Can I make a circuit relatively easily to cut the frequency in half or fourths?

Brian

M_T_0

Cut off 1/2 the teeth on your home made reluctor wheel. or better yet 9/10s of them should get you into 100hz at 40mph

More Than Zero

John McGraw

Contact Dakota Digital, they make a module to do just this. I use them to convert the PCM output to the correct input for an electronic spedometer. You can convert a number of different inputs to a number of different outputs, and you can fine tune the outputs to get exactly the right range by using the calibration adjustments.

Regards, John McGraw

JOHN LAWSON

iTrader: (3)

John, I sent you a pm can you get back with me? Thanks John Lawson