Yanmar 3YM30 Oil Pressure Issue

[PPLepew]

Unlike an earlier forum entry, my oil pressure alarm does NOT beep.
Arriving at an anchorage, dropping anchor at idle, my pressure alarm started to chirp and stopped. I immediately turned engine off for later investigation.


Next day, engine cold I turned on ignition an the pressure alarm did not beep as engine wasn't even started. I shortened the pressure sensor wire to the block, nothing.


Two possible reasons (to me) were a cut wire or a dead buzzer. Any other possibility?


Following the wire through several harnesses to the panel is close to impossible. The wire is yellow and I only have one yellow arriving in the connector at panel; can shorten it to the ground to test the buzzer with ignition on? I'd hate to fry the circuit board

[a64pilot]

Could be the switch too, I’d think more likely the switch.
Try wiggling the key with the engine off and see if you get an intermittent buzzer. Turn off and on a few times

[PPLepew]

Tried the wiggle of key and wires by panel. No go.
Can I damage anything by leaving the ignition on while I crawl around the boat and wiggle harnesses?

[a64pilot]

Originally Posted by PPLepew

Tried the wiggle of key and wires by panel. No go.
Can I damage anything by leaving the ignition on while I crawl around the boat and wiggle harnesses?

I don’t see how, maybe over time you will deplete the battery if your not hooked into shorepower.
Way back when we had point ignition in gasoline engines, I believe you could hurt the points, but other than battery drain,
I don’t believe anything is hurt on a Diesel and or newer cars either.
Some boats will run a blower when the key is on, but I don’t think it’s harmful.

[PPLepew]

I already disconnected the blower. The whole operation could maybe take 45 mins of contortion and sweat, and I'll have a power charger on the battery.


Main question is, assuming the wire good, can I bring ground wire to test the panel beeper without frying it. That's what the wire does anyway, no?

[a64pilot]

I can’t answer cause that is a vague question, you ground something that has power, yes of course you could damage the circuit.
I would say that I think it unlikely you would damage anything if you tested the wires for continuity, and that it where I would start.
I’d try to get a schematic for your panel first though

[GordMay]

Basic Troubleshooting of Gauges:

All Gauges:

1. Remove Sender Wire from “S” Terminal on Gauge, and Turn ON Instruments Circuit.

2. Test Voltage between “I” Terminal (External Power Supply) and Ground Terminal “G”.
Tested voltage must match nominal voltage of the Gauge (ie: 12V Gauge must test between 10 - 16VDC), and the Battery Voltage.
If no voltage - check Ignition or Instrument Switch(s) and/or Fuses.
If tests less than battery voltage, repair or replace (Violet) wire from Ignition or Instrument Switch.

If a Sender fails “Open” (Infinite Resistance), one or both (if Dual Station) Gauges will read Zero Scale.
If a Sender Fails “Closed” (shorted - Zero Resistance), one or both Gauges will read Full Scale.

Other confusing Ohmmeter results, such as readings lower than expected, could indicate a poor Ground Connection at the Sender Body (Sender to Engine Block). Check for pipe dope or tape on Sender Threads.

Pressure Gauges:

1. Disconnect Dark Blue Sender Wire from Gauge, and turn power ON.
The Pressure Gauge should read ZERO Scale (Low Pressure).

2. Short the Gauge Sender Terminal to Ground.
The Gauge should deflect to FULL Scale (>High Pressure).

3. Measure Resistance from Dark Blue Sender Wire to Ground.
American Press. Sender: 240 Ohms (Zero Pressure) 33.5 Ohms (Full Pressure @ 80 psi)
European Press. Sender: 10 Ohms (Zero Press.) & 180 Ohms (Full Press. @ 150 Bar)

See 4, 5, & 6 above (but Dk. Blue Wire)

4. Disconnect Tan Blue Wire from Sender on Engine Block.

5. Test continuity of Tan Blue Wire.
Zero Ohms from Block End to Gauge End - If not, repair or replace Wire.

6. Measure Resistance from Sender Terminal (on Block) to Ground on Block.
Should read as per (3) above - If not, replace Sender.

From ➥ http://www.cruisersforum.com/forums/...sting-645.html


See also:

Wiring Diagrams:
http://www.cruisersforum.com/gallery...=500&userid=79

Testing Instructions:
http://www.cruisersforum.com/gallery...=500&userid=79

Sender Resistance:
http://www.cruisersforum.com/gallery...=500&userid=79

[S D Sailor]

I've had a variety of gauge, alarm and other electrical problems centered around the switch panel/dashboard at my helm station (2010 Leopard 384....not the B Panel, the old one with 2 rocker switches). All have been solved by cleaning the contacts behind the switches (fine sandpaper & spray Electrical/Contact Cleaner). Lots of corrosion...
Hope this helps.
Fair Winds,
Richard

[PPLepew]

First, I don't have a pressure gauge, just an alarm (B panel).
New sensor tested good, I have continuity between body and the pin, this should be interrupted when pressure is on.


Disconnected wire on sensor and panel and tested its continuity, there was none. Next step is to quick run a test wire from sensor and panel and start engine. Beeper should stop within a second or two. If this is the case, problem solved, I'll thread a new wire through hull, harness, feeds.



And check it again.

[PPLepew]

Before cutting wire, I wiggled/twisted the harness slightly wherever I had access to it, hoping to get continuity back, never got even the faintest beep.

New wire threaded through. Success. I never been happier to hear an oil pressure alert..
Thanks to all.