Map Sensor and power logger hybrid


West Coast Newfy
Jul 17, 2007
I have a 71 Vega with GN running gear stock computer and wiring harness, the vega wiring runs lights and the starter I have an auxilary fuse panel for the engine managment, alky kit, wideband and fuel system. The C100 bulkhead connector has been eliminated along with that wiring.

So I wired my power logger to the green wire terminal A on C437 like I had it in the Ttype and nothing, the connector is not connected to anything and I have ran power to terminal F to run the motor, there is no power at the map sensor and I have probed the C437 connector terminal G black and white marked as ground has 5 volts? Nothing at terminal B I jumped the G and B together and got a reading of 20 PSI on the powerlogger? Is it as simple as grounding terminal G?


  • GN_C437.jpg
    48.3 KB · Views: 109
the reason you have nothing is the map gets its power and ground through that connector from the dash harness tach boost module , you need to run a wire from the tps gray at ecm (pin C14) to pin B (gray) at that connector that will provide 5v to the map connector underhood
then you need to connect the ground on that connector (G blk wire ) to the tps ground at ecm (pin D12 blk)

with 5v at gray wire at map connector and ground at blk wire of map connector the center pin B green wire will have the map signal which for a 3 bar map whoul show 1.6v key on engine off, for a 2bar it should show approx 2.5v
Last edited:
safest for proper reading is to use the 5v low ground at ecm but it will work if just connected to chassis