The issue I'm having is my 88 LX-I is not starting after performing an engine swap with a rebuilt stock engine. It cranks and has spark, but there's no fuel, pump doesn't come on. I've followed all the troubleshooting steps in the FSM. The pump is not bad because if you directly supply 12 V to it, it comes on.
I've narrowed it down to the harness at the main relay. The main relay operates as it's supposed to when voltage is manually applied from the battery to the correct terminals.
When measuring the IGN SW wire relative to GND on the main relay harness connector, at key off it reads -0.45 V. At key on, it reads 0.6 V. However, when reading the IGN SW voltage relative to the negative terminal post on the battery, it reads 0 V at key off and 12 V at key on, as it should.
So clearly there's something wrong with the ground wire in the connector, however I'm having trouble following the harness through the firewall into the engine bay.
Is this a common issue or does anyone have an idea what would be causing this? I would think a wire shorting would blow a fuse or have it always be 0 or 12 V. Any help is much appreciated
Summary: GND in main relay harness reads 0.5 V relative to battery negative post with key off. Reads 11.5 V when key on.