razzmtazz Posted October 15, 2023 Report Share Posted October 15, 2023 hi i am trying to run the factory speedometer through the g4x plugin ecu to correct an over speed reading issue but the speedometer does not respond to the pmw test help would be appreciated r33gtr running 10-15-23.pclx Quote Link to comment Share on other sites More sharing options...
AbbeyMS Posted October 15, 2023 Report Share Posted October 15, 2023 the factory speedometer sees the signal from the output sensor in the gearbox before the ECU. With a little wiring you could rewire the set up to do what your trying to do. Output sensor = ecu - speedometer Quote Link to comment Share on other sites More sharing options...
razzmtazz Posted October 15, 2023 Author Report Share Posted October 15, 2023 12 minutes ago, AbbeyMS said: the factory speedometer sees the signal from the output sensor in the gearbox before the ECU. With a little wiring you could rewire the set up to do what your trying to do. Output sensor = ecu - speedometer Yes it's now sensor to ecu and to ecu to speedo have not driven the car but the pwm test doesn't work and no sweep also Quote Link to comment Share on other sites More sharing options...
Vaughan Posted October 15, 2023 Report Share Posted October 15, 2023 The Nissan gearbox speed signals are a VR type not a hall type so you need to convert the square wave output from the ECU Aux to a VR style signal to make the dash recognise it. I can't remember the exact values of the capacitor and resistor required but there is a diagram of it somewhere in the forum. @Adamw might have a copy of the diagram saved. Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 15, 2023 Report Share Posted October 15, 2023 I used the circuit below to make a Nissan speedo work from an ECU aux out. Basically you need a pseudo "AC" waveform that crosses zero. I cant remember if this was a skyline or an S chassis as it was several years ago, so no guarantees it will work for an R33, but at least the bits needed should only cost a couple of dollars to give it a try. Simulated waveform: Quote Link to comment Share on other sites More sharing options...
razzmtazz Posted October 16, 2023 Author Report Share Posted October 16, 2023 Thanks guys for the help it works but muli had to be set at 1.6 for full sweep Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.