260 Tach, rectifier

[Cervelo777]

I just got done rigging my Allison XB2003 and the first test run was, in general a success, Just a few bugs to work out. The tachometer worked intermittently. I have spent the last four days reading over 40 pages of posts related to the subject and I see the Promaxes seem to blow the rectifier/regulator often. One of the solutions for them is to connect the grey wire to the other regulator/rectifier. I think my 260 only has one rectifier? It is pictured below, with two yellow wires going to it. Question is will my tachometer work any different if I connect the grey wire to the other pole? I suspect that the other probable cause could be a bad ground somewhere. My plan of action would be to first connect the grey wire to the other pole, if that does not solve it, I will run a new ground from the battery to the gauge, if that solves it I will go on the hunt for a broken wire or inadvertant grounding somewhere. I sure would appreciate any thoughts. Does anyone know that part number for the rectifier on a 260?

The other issue is my fuel pressure gauge shows 38lbs at start up but then slowly drops to about 22-25lbs even when running, would this scare you? It seems to run fine, I am only brave enough to go 75 on my first run, it seems to have a whole bunch more!!