Burnt Up 10 Pin Connector 89 Gt

The 30 second delay was the computer shifting from open loop to closed loop. Open loop operation uses a set of fixed parameters and minimal input form the sensors. It is used on startup to give the engine a chance to get warmed up a little and settle down. In open loop, EGR is turned off and the smog pump directs air to the cylinder heads instead of the catalytic converters.

The VREF can be checked by measuring the orange/white wire for 5 volts +/-.5 volts at the MAP/Baro sensor, then the TPS and the EGR. If you see good 5 volts VREF at the MAP/Baro sensor and a bad reading at both the TPS and EGR, the 10 pin connector is suspect. A bad reading on only one of the engine mounted sensors is a broken wire in the engine mounted fuel injector harness.