Velvet drive 1200 rpm light on and sync gauge wrong?

[boatbum]

2000 Trojan 454 with Velvet Drives

Oil is topped off
Temp is perfect
Already changed the Temp sensors, waste of money
Changed the Pressure sensors and port motor velvet drive light is still on after 1200 rpm, starboard goes off as expected.

Then I noted that the sync gauge is way off on the port motor, way short on rpm's and appears to get worst are the rpm increase.

How are the velvet drive warning lights tied to the motor rpm and maybe even the sync gauge? Suggestions, please?

[waybomb]

I believe the indicators are pressure sensitive only.

[mjk1040]

Sync is electronic and works off the rpm gauge feed. I was told tach's may be off, but the sync was more accurate. I'm going to take a shot in the dark here, find your main wire harness at the engine and have someone wiggle it with engine running and watch your gauges. I'll bet you have a harness plug issue, signals not getting to gauges. Sometimes it's the simple things that cause the biggest problems. Mike