mpguino vss signal problem

[meckbar]

Hello fellow modders, newb here, i have been searching for days with no luck on this problem. I have a 95 honda del sol and when i hook up to the vss wire, there is no reading on the mpguino and my speedo/odo stops working. I disconnected the mpguino vss wire and my speedo/odo starts working again. Is there a resistor or diode that i need to put in-line? Also, does anyone have any numbers for the setup so i at least have a starting point to calibrate? any help would be greatly appreciated. thanks

[bobski]

This is a pre-built MPGuino?
A table of calibration info is available on the wiki.

[meckbar]

Yes its a pre-built model, checked out the wiki and put in the numbers for the vss for the honda's but didn't help. for some reason when i hook up the mpguino it kills the signal to the dashboard or draws too much of the signal and they both don't work

[bobski]

Yeah, I ran into that when I tried direct-driving an optoisolator with the VSS signal. The VSS really doesn't put out much current, so it's easy to drag down the signal so the ECU, speedo and cruise control can't see it. That shouldn't be a problem with the MPGuino's VSS input circuit... It's pretty low-draw. I've used the same configuration on my own creations.
Re-check your wiring connections... There might be a loose strand of wire shorting the VSS line to ground. Check the car end of the wires too.

[meckbar]

well, double checked my connections and found one strand of wire going from the 12v to vss at the mpguino connector. took the car out for a spin and so far it seems to be working, now time to calibrate. thanks for the help.

[bobski]

Originally Posted by meckbar

[...] found one strand of wire going from the 12v to vss at the mpguino connector.

That's all it would take. Have fun.