Stig,
What sender are you using?
I had a similar problem with my set up (Stewart Warner) using originally a Hall Effect sender in the gearbox and subsequently a proximity detector against a bolt head on the drive shaft...
Both of these seemed to produce a decent shape output when tested with an oscilloscope, but eventually I found the problem was that the output, while a nice shape, was of insufficient amplitude.
This was partially cured by building a simple amplifier using the stabilised 12 volt supply provided to the instruments....
Even this was not 100% reliable, and eventually I resorted to a good old fashioned mechanical drive... worked beautifully!
Regards
Neil
What sender are you using?
I had a similar problem with my set up (Stewart Warner) using originally a Hall Effect sender in the gearbox and subsequently a proximity detector against a bolt head on the drive shaft...
Both of these seemed to produce a decent shape output when tested with an oscilloscope, but eventually I found the problem was that the output, while a nice shape, was of insufficient amplitude.
This was partially cured by building a simple amplifier using the stabilised 12 volt supply provided to the instruments....
Even this was not 100% reliable, and eventually I resorted to a good old fashioned mechanical drive... worked beautifully!
Regards
Neil