Might need a new ecu.

Conflicting info online about the rear temp sensor head is necessary for starting. 6 months ago it ran fine on a blown head gasket without the sensor. 1997 3rz-fe 4x4 manual trans.

Yes, all 4 brown wires on the ecu (left plug as it appears behind the glove box) are at ground potential. (+.2 volts relative to chassis during starting) I can identify 2 of the injector wires at the ecu are only pulled 1 volt down from 12.5 volts during starting. So the injector sees pulses about 1 volt. Have not located the other 2 wires.

Tachometer works once enough fuel (propane) is dumped in the intake, so the camshaft sensor works. Unplugging it throws a code.

Spark is verified.


And i put a 10k ohm ntc resistor across the connector and it fired right up!