Floscan TwinScan Tachometer - Manual (Page 18)

3/13/2002 1000-223-00
FloScan Instrument Company, Inc. Tel: (206) 524-6625 Fax: (206) 523-4961
3016 NE Blakeley Street, Seattle, WA 98105 Email: [email protected] Http://www.floscan.com
• If 12 VDC is not present, measure between the RED, or RED/WHITE power wire and a known good
ground in the instrument panel. If you measure 12 to 14 VDC there may be an instrument ground problem.
__________VDC
• If 12 to 14 VDC is not present check wiring, switches, fuse, and the 12 VDC power source.
III. CONTINUITY TEST
• Continuity testing requires access to the back of the Instrument and an Ohmmeter. It verifies that wires are not
broken, shorted to ground, another wire, or to power. Before starting, secure all power. You will be testing the
VIOLET, and YELLOW wires.
• Disconnect the Yellow wire harness conductor from the Port Tachometer Sender & Instrument wire.
Connect a jumper from the YELLOW wiring harness conductor to a known good ground. At the
Instrument, connect an Ohmmeter lead to its’ YELLOW wiring harness conductor. Connect the other ____________
Ohmmeter Lead to a known, good ground. The Ohmmeter should read approximately 0.1 to 3
Ω.
(Ohm Reading)
• Disconnect the VIOLET wire harness conductor from the Port Tachometer Sender & Instrument wire.
Connect a jumper from the VIOLET wiring harness conductor to a known good ground. At the
Instrument, connect an Ohmmeter lead to its’ VIOLET wiring harness conductor. Connect the other ____________
Ohmmeter Lead to a known, good ground. The Ohmmeter should read approximately 0.1 to 3
Ω.
(Ohm Reading)
IV. TACHOMETER PROBLEMS
Note: Refer to the engine owners’ manual, wiring diagram, installation, and calibration instructions for parts A, B, & C below.
A. NO READING.
• Check continuity of the YELLOW and VIOLET Tachometer signal wires, (Section III). Verify that the tachometer signal wires
are connected at the correct signal output point.
B. HIGH OR LOW READINGS.
• Verify that Tachometer is calibrated correctly.
C. FLUCTUATING READINGS.
• Listen to your engine(s). If engine speed cycles up and down, (when idling or underway) the tachometer reading will follow. This
does not indicate a problem with the Tachometer, but may indicate engine problems.
• Verify that wiring connections are tight, clean and dry. Check continuity while shaking the wires. Ohm readings should be near
zero and remain steady.
• Verify that the tachometer signal wires are connected at the correct signal output point.
This concludes system testing. If problems with your system persist,
contact FloScan Technical Support with testing results.