Well I would start by disconnecting the oil and temp gauges at the sending unit's Ground the wire to A good known ground one at A time and turn the key on, if the gauge pegs out it's the sending unit. if not it,s wiring or the gauge it's self. your voltage limiter must be functional if the gas gauge works. try that to start. and Welcome aboard. Mark.
Thanks js29 I'll try that. All gauges are new and tested them they are good have a new harness in engine bay and dash. It did this even before new harnessWell I would start by disconnecting the oil and temp gauges at the sending unit's Ground the wire to A good known ground one at A time and turn the key on, if the gauge pegs out it's the sending unit. if not it,s wiring or the gauge it's self. your voltage limiter must be functional if the gas gauge works. try that to start. and Welcome aboard. Mark.
Not to insult your intelligence, but they're not wired backwards, are they? There are letters cast into the housing that tell what color goes where.