few pages down.
We have found better overall operation of the FM ECU when the following modi cation is made to the ECU ground wire circuit.
4) Locate the two Black/Green wires coming from the 2C and 2D pins and follow them back to where they are spliced into one wire. These wires are signal ground wires that carry small amplitude signals to a ground point. Cut this single wire after the junction.
5) Crimp the ECU side of this wire into one end of the yellow butt connector. Take the 6 gauge wire included with the ECU and crimp it into the other side of the butt connector. The remaining chassis side of the wire can be taped off to the wire harness. It will be unused.
6) Run the new 16 gage wire through the rewall. Behind the windscreen washer bottle there is a plugged hole that is perfect for running this new wire. There is a photo of this hole on the next page.
7) Run the new ground wire behind the engine to the bolt that holds the ground strap con- nected to driver’s side rear of the cylinder head. Refer to the photo on the following page.
Note: Do not add 2A and 2B to this connection, as these are power grounds and they will neg- atively affect the signal grounds.
8) Clean the points where the ground strap contacts the body and the head with ne sand paper.
9) The minimum changes required to make the Flyin’ Miata ECU function in the car have been completed. The following steps will enhance the operation of the ECU and the car, but they are not required. If any or all of the optional steps are going to be made, return to steps 10 & 11 to close up the ECU. If none of the optional steps are going to be made, go to step 10 now.
0) Reinstall the steel panel over the ECU and plug the ECU plugs back into the ECU. Put the carpeting back down and reinstall the plastic trim on the door sill.
) Reconnect the battery.
Thought I give it ago. As I've changed a few things. Bugger knows if its effected anything. But I ran it to the block to bulkhead ground. Rather than the white GND block.
Since remove the GND wires that bridged all of them together in the ECU. I've noticed my TPS is very slightly more noisy. Still stable but I could notice it.
I've attached a log file of WOT with the changes. Much better voltage readings.
AFR have dropped also. Hitting 10.6 rather than the old log 10.9 / 11.0