Hi Ron, thanks for the info. The engine harness diagram I have and the ECU pinout diagram I have are for a 94 so some of the colors are different but the connector pinouts seem to be the same so I've been able to follow them. My diagram shows it should be a 8v feed for that sensor and it's only reading 7.4v. I had the battery charger on it for a while and topped up the battery before checking. Not sure if 7.4 is unusual. I'll check out grounding the 5v wiring in the morning, but it was showing 5v when the crank sensor was unplugged, dropping down to around 2.5v when the sensor was plugged back in. Thanks, Tristan.