Hi, I've tried to find answers on vehicle specific forums but had no luck so I'm hoping some specialist auto electrician can help.
i have a 1994 Mazda MX-5 1.8 and I'm trying to connect a Race Technology DASH2PRO.
I'm having some trouble with THE RPM readout. I know it used to work when I first fired up the MX-5 engine to test the wiring.
Now the wiring is in the car the RPM doesn't work at all. The way the tacho signal comes is there is a black/white wire coming from each of the two coil packs which merge into one wire. Then it splits back into three, one going to a pin on the ECU, another to the diagnostics port and the other to drive the tacho. When ignition 2 and the engine is running around 12v is being output on the wire to the tacho, however when I connect this to the DASH2PRO RPM input (yellow wire on connector B) the signal drops to around 6v and no RPM is displayed. I've even disconnected all other wires from the DASH2 so its just power and RPM.
Connecting the original Mazda dash back up shows the RPM working and the tacho wire staying at 12v.
Ive traced the wires and they look ok, no breaks or shorts. And I've had the DASH2PRO unit tested by the maker today and it is working fine.
Why when adding the dash to the circuit would the voltage be pulled down by half?
Thanks
i have a 1994 Mazda MX-5 1.8 and I'm trying to connect a Race Technology DASH2PRO.
I'm having some trouble with THE RPM readout. I know it used to work when I first fired up the MX-5 engine to test the wiring.
Now the wiring is in the car the RPM doesn't work at all. The way the tacho signal comes is there is a black/white wire coming from each of the two coil packs which merge into one wire. Then it splits back into three, one going to a pin on the ECU, another to the diagnostics port and the other to drive the tacho. When ignition 2 and the engine is running around 12v is being output on the wire to the tacho, however when I connect this to the DASH2PRO RPM input (yellow wire on connector B) the signal drops to around 6v and no RPM is displayed. I've even disconnected all other wires from the DASH2 so its just power and RPM.
Connecting the original Mazda dash back up shows the RPM working and the tacho wire staying at 12v.
Ive traced the wires and they look ok, no breaks or shorts. And I've had the DASH2PRO unit tested by the maker today and it is working fine.
Why when adding the dash to the circuit would the voltage be pulled down by half?
Thanks