i know that during the recall or whatever that mazda had on the 86 rx-7s they spliced another ground into the pressure/boost sensor wich also tied into the air flow meter and other things... by looking at an engine harness diagram (wasnt the best diagram) i believe it is the brown/black wire that needs to be grounded. anyone else here know?

 

I think you're right about it being BR/BL. To make sure, check the voltage on that wire. Should read 0 volts or near to it. Splice a 10-12 guage wire to that wire, solder it and tape it well. Ground it to a bolt on the car's frame. Make sure the ground point is clean metal and not painted. Sand off the paint to get to clean metal if you have to.

 

its not a recall, it fixed 1 guy's car and he put it on the internet.



the factory bulletin is for the ground on top of the engine, its the rear most emisison rack bolt.