Volvo Penta Tachometer Calibration Button?

[oshinnvoyages]

Good morning & thanks in advance for the assist!

Issue: I need to calibrate the tach that I replaced. I can not find the calibration button.



Components:
- Volvo Penta D2-60F
- Volvo Penta tach #3885694

Background: replaced broken tachometer with same model. Replacement did not come with a manual or instructions - just the tach and wiring harness. I found the code table, I just need to find the calibration button. I've tried each of the three holes on the back of the tach - none of them felt like anything moved when pressure is applied. No separate button on the wiring harness.

Current status: When turning on power, the "VOLVO PENTA" message displays, but then the display goes blank. No RPMs are shown on the dial. 20-second video (4MB)

Thanks in advance!

[GordMay]

It may have a plastic/rubber plug, in the back [black circle @ 12 O’clock hi?], which you can remove, to access a small adjusting screw.

[oshinnvoyages]

Thanks, but that isn’t a rubber plug - it’s a hole that has what appears to be a clear plastic disc about 2mm below the opening. It has two black lines in an X across it. But it doesn’t depress or move.

Originally Posted by GordMay

It may have a plastic/rubber plug, in the back [black circle @ 12 O’clock hi?], which you can remove, to access a small adjusting screw.

[hlev00]

I really only familiar with Yanmar tachs, but the video looks more like a wiring issue than calibration. Maybe it is getting power but no tach signal? Some tachs pick up from the flywheel. Others pick up from the alternator.

[DougR]

I have been out of the VP loop for awhile, and EVC tachs might have changed in the mean time, but in the past there was no need to calibrate an EVC tach, hence no calibration button.

The EVC tach drive signal is riding on the can bus with the rest of the instrumentation data and this signal is produced by the MDI box in the D1 & D2 series engines, and by the ECU on the other electronic engines.

If there is no tach drive info on the can bus you might want to check the inductive tach drive sender mounted in the flywheel housing to make sure it’s not loose, make sure it’s clean and hasn’t picked up some debris, make sure the wiring connections are good, etc. Check the continuity into and out of the sender. The resistance should be about .9 K ohms. If you connect a multimeter to the sender, set it to AC volts and wave a screwdriver tip across the sender you should see a slight AC voltage reading.

Also check the wiring harness pins where the connectors enter and exit the MDI box.

[oshinnvoyages]

Thanks so much - solid info and I'll get that checked as soon as I'm back on the boat.

Originally Posted by DougR

I have been out of the VP loop for awhile, and EVC tachs might have changed in the mean time, but in the past there was no need to calibrate an EVC tach, hence no calibration button.

The EVC tach drive signal is riding on the can bus with the rest of the instrumentation data and this signal is produced by the MDI box in the D1 & D2 series engines, and by the ECU on the other electronic engines.

If there is no tach drive info on the can bus you might want to check the inductive tach drive sender mounted in the flywheel housing to make sure it’s not loose, make sure it’s clean and hasn’t picked up some debris, make sure the wiring connections are good, etc. Check the continuity into and out of the sender. The resistance should be about .9 K ohms. If you connect a multimeter to the sender, set it to AC volts and wave a screwdriver tip across the sender you should see a slight AC voltage reading.

Also check the wiring harness pins where the connectors enter and exit the MDI box.