Does anyone know where the Tach signal wire from the ECU is on a 1992 F250 7.5 liter engine. I need to tap into this signal to wire in an air fuel monitor. I'm not talking about the yellow wire coming from the coil, this signal is to strong I need the signal from the ECU. Thanks.

 

A Air/Fuel gauge uses the signal from the oxygen sensor not the tach signal.
On this schematic from AutoZone it shows pin 29 on the ECU a Gray/Light Blue wire.