Merc smart gauges + fuel gauge issues

[Budgie1]

Smart gauge was working fine for my 2006 75hp Opti until I started tinkering Reset the fuel used, must have got something wrong as its too much of a coincidence its know all over the place!! Rev counter dances around 3 to 4500rpm even when engine is not started, engine hours back to zero, used abot 300 litres of fuel to do couple miles etc, dont think it is in cal mode, have tried disconnecting/reconnecting but no joy. Am considering master reset as last resort but hoping the more experienced may be able to offer advise first.

Virtually simultaneously the fuel gauge stopped working when I turn the ignition the fuel gauge goes up to 3/4 then gradually returns to empty! dont see how the two can be related but bit of a coincidence??!

Any advise welcome

[Nos4r2]

How's the fuel gauge get it's reading?Via the smartcraft/NMEA network or independently?

(FWIW, random wierdness across multiple systems is usually down to a dodgy earth somewhere in the system, but all bets are off if it's a problem with the fuel/ignition computer)

[Budgie1]

Had another quick look tonight, when I turn on ignition it should display software release, then engine hours, what It actually does is display software release, then Stn1 followed by fictitious engine hours (can't find Stn1 mentioned in manual) finally RPM progressively increasing (with engine stopped) possibly earthing but seems such a co incidence it started after I tried to reset 'fuel used' to zero

Excuse my stupidity but no idea if it is smartcraft NMEA network or independent (how do I tell?) it has one D type connector which is just push fit

[Bigtalljv]

I'll second the ground issue. I had much gauge weirdness in my land vehicle when the ground to the instrument cluster came loose.

jason

[peterwhite]

I'd say your gauge is knacked. I have changed a few of these over the years identical symptoms.

[Budgie1]

New gauge fitted but still not 100% functioning correctly ..... Trim not correct but think I can reset, but its also giving false readings for 'fuel used' reset to zero did 35nm and it claims I've only used three litres (wishful thinking!!) spoke to the marine engineers and they are happy I take it back but they don't sound confident what the problem could be as it is plug and play. Previous gauge was giving good indication of fuel used so can't believe it's anything other than gauge? Do I need to calibrate tank capacity or something??

Looked on line, manual etc can't find any relevant info

[Budgie1]

Problem solved .... school boy error, it was set on gallons not litres