Floscan for a Volvo 41B wire help.

[Sleigher1]

Hi All,
I am installing a Flo-Scan on my AD41 B.
The tach was very erratic and I had always wanted to know my optimum cruise speed so I went with the Flo-Scan. 750M-BOS-2K.
My question is what are the "W" and "G-" terminals on the back of my Volvo Tach?
I am pretty sure they are for the tach.
I connected them to the wires for the Flo-Scan and when I run the engine I get either "0" or "9999" depending on which way I connect them.
"W" to the yellow wire (from Flo-Scan) and Violet (from Flo-scan) to ground gets 9999.
G- to the yellow wire and violet to ground gets 9999.
W to the yellow wire and G- to violet wire gets 0
W to the violet and G- to yellow gets 0.
The tech person at Flo-scan says that I am probably wired correct but just need to calibrate. (with the first configuration). This is good news but then I have an extra wire (G-).
Any help is appreciated.

Thanks,

Peter

[NoSlack]

Do you have the wiring diagram for the 41? If not, let me know and I'll send you a PDF copy of it. What I see is the G terminal on the tach goes to pin 12 on the wiring harness and ends there. There is nothing connected to pin 12 on the engine end of the harness.

From the Flosan book• Engine Alternators: Connect the FloScan tachometers Yellow signal wire to the alternators’ tachometer output terminal. This terminal is usually marked as TACH, or SIG. Connect the VIOLET wire to a Ground Buss, or Battery Minus.

You should be able to land the yellow on the W terminal of the tach to pick up the signal.

See page 24 for the calibration http://floscan.com/html/Manuals/7500_75000_MFI.pdf

Tach that come off of an alternator are never very accurate. If you want accuracy, install a magnetic pick up on the engine and wire the yellow and violent to it. The 40 engines use a mag pick up not the alternator to drive the tach.

Go to this link and look at part #22 http://www.marinepartseurope.com/en/volvo-penta-explodedview-7742700-21-1676.aspx My bet is your engine has a plug in tach sender hole, if there is a hole. Some of the 41s have a spot for the sender some don't.
Mike

[yellowfin1]

Hi Peter,
I've got the AD41P and also have the flow scan. I have the analogue model. If you have not figured it out yet, you are welcome to stop by my house in Clairemont and check it out, or just give me a call and I'll check out my wiring (858) 229-2261. I love my flowscan. I have done the initial calibrations and it seems to be spot-on. The only gripe I have is that I've had to replace the sensor on the intake side twice in 4 years. Not a big deal though.

Scott

[Sleigher1]

Thanks Guys,
I have the wire diagram for the 41s and like you said (Mike) the one wire goes nowhere.
It does leave the tach (G- terminal) and go into the harness.
That wire to ground gave me around 7 volts so I figure it has to be connected to something.
Unless I am getting a backfeed through the ground but that wouldn't make sense either.
I am hoping that once I get it reading something I can use my photo-tach to get it dialed in.
I have the Floscan directions for calibration I am hoping that I can get close with the coarse (red dial) and then nail it with the green. I just thought that it would give me a reading somewhere close upon initial start up.
I haven't been able to hook a hose up to the boat to test yet. Maybe this weekend.
The other issue is the wire that is now hanging loose back there. Too many of those.

Peter

[Sleigher1]

Well, all it took was calibrating.
I used the "W" wire to the yellow and the violet to ground.
All I had to do was turn the red dial one click and I was in the ballpark.
Worked with the green and red till I was withing about 20 rpms of what my photo-tach was telling me.
Sped it up to 1850 and the photo tach read about 1820 or so which is as good as I think I can hope for.
I guess that I am just so used to plug and play that I figured it should have at least been close from the get go.
Thanks for the help.
Never did find out what the "G-" wire was for. I just zip tied it to the harness for future perplexation.

P