Digital guage help needed!

[Hollywoodfish]

I have twin 150 HPDI's (2001). Here is my guage set-up. 2 Tachs, Speedo (Mainly used for Batt & Fuel level), and Fuel Managment.



The fuel managment guage is the one giving me a problem. The Synch does not work (it used to). The fuel burn is not correct (total and actual). I filled the tank and fished for two days, the total burn read 54 Gals and then I pumped 90 in. While cruising it shows actual burn anywhere from 5 ish to 12 ish, but it should be more like 20 something ish. I am not sure if it is the guage, a wire, or some other issue. How can I diagose the guage? Will 6Y8-83500-11-00 be compatible with my set-up? Also, will this guage tie in W/ GPS for speed? My current speed always reads 4 on the guage.

What is my next step? I don't really feel like forking out a few hundred bucks for a guage to only find out that was not the problem. Thanks

[boats.net]

It's probably a bad fuel flow sensor or wiring to flow sensor, check wiring and remove sensor and inspect paddle wheel inside it.
No the 6Y8(Command Link) gauges wont work on engines older than 2006.
The Fuel Management gauge will connect to GPS for speed signal.
FMM GPS Connection.JPG

[Hollywoodfish]

OK, so just to get things straight...... If the fuel flow paddle wheels look ok and spin fine then it may be a wire issue, correct? And you are telling me that the 6Y8-83500-11-00 guage will not work on my 2001 motors, but if I get the wire 6Y5-85721-F0 I will be able to tie my current speed guage into a gps.

I can you this though. The fuel flow sensors look rough, They have alot of corrosion on the exterior of them. I will take them out and inspect and clean up the wires. Upon initial inspection I took a quick look at the port side and see that off of the pigtail there are two wires that are spliced in. Does this sound right. Ill try to take pics. Thanks for the help so far.