RPM playing up

I had been experiencing some issues with an RPM reading on my infinity multi gauge unit and although the airspeed and EGT, CHT, Oil Temp and Pressure were all reading fine the RPM was defiantly playing up and not reading.

I had given up on the photo cell unit in the early days as I just couldn’t get it to work but on checking with another fellow builder (Danny Baker – who has been a great help) he advised he had spliced into the regulator-alternator circuit and set for 5 pulses per revolution.

Still couldn’t get a result so needed more investigation

Yesterday I finally found something .. I had chosen in my wiring to not use totally white cables to aid any problem resolution and identification later. I had also put a number of ‘spare’ cables into the 3 harnesses I had built in.

I had one spare BLUE cable – I thought … And had terminated this with a handshake connector and sheathed it. On re- checking, I had put two blue cables in and connected one to the Yellow of the regulator passed this through the bulkhead and to the rear of the panel. It was this one I had accidentally terminated and secured (without connecting!)

Both the RED and the YELLOW from the regulator need to connect to the positive bus.

Connected up and bingo ! I have a nice solid reading on the top of the Infinity gauge and also now have a big positive charge going into the battery ..

Learning all the time !!