S# D187 GMC engine closed loop system ,
Unit will not start first thing then after it is started once , starts all day
did some test
the fuel idle solenoid on top of regulator does not open,but once bypassed with jumper wires unit starts
While testing with test probe both sides of plug are hot ?
My question what gives this unit a signal? Relay? cold start solenoid ? or is this controlled by the ECM