Yamaha 1986 220HP oil pump not stopping

[snaphead101]

Mate I just got a reply back from a moderator on my post saying to check the filter is permeable to the oil. Makes sense, as if the filter was clogged, then oil would not flow in thus the gauge would drop switching on the pump. Why this is intermittent I don't know, maybe the viscosity of the oil changes with temperature ???? Anyhow have washed out the whole system with fuel and changed the oil. If this works I'll let you know (will have to wait for Yasi to rack off before I get out again !).

[Bullet1750]

Mate I just got a reply back from a moderator on my post saying to check the filter is permeable to the oil. Makes sense, as if the filter was clogged, then oil would not flow in thus the gauge would drop switching on the pump. Why this is intermittent I don't know, maybe the viscosity of the oil changes with temperature ???? Anyhow have washed out the whole system with fuel and changed the oil. If this works I'll let you know (will have to wait for Yasi to rack off before I get out again !).

The problem I have is the pump does not stop even when the engine mounted tank is full. It overflows into the carburettor inlet (Via the overflow) and eventally starts to push the float mechanism out of the bottle.

[snaphead101]

If oil is flowing slowly into the chamber where the float is located, then eventually the float will be low enough to turn on the pump. The pump then will pressurise the oil reservoir and if not enough gets through the filter to raise the float either the top of the float chamber bulges off or oil is forced out into the carbys. I must however admit that it seems pretty unlikely that the filter chamber should become intermittently semi-impermeable. I know it's clutching at straws, but apart from a gremlin in the ECU and possibly megabucks I can't work out much else it could be.

My engine has twice had this problem, although both times at the end of the day.

[rodbolt17]

there are no overflow tubes on any yamaha engine oil tanks, there is a vent line.
the V6 2.6L precision blend history for the US market.
1984-1989 system used a seperatly mounted oil transfer pump control module.
module used a mercury switch to inhibit oil transfer when tilted.
module had a funny habit of turning on the transfer pump if module voltage dropped below about 9V.
what could cause 9v at the module?

1990-1995 oil control module was incorperated into the ECU and the mercury switch was eliminated.
now the trim sender signal was routed to the ecu/oil module and after a certian trim up the oil transfer pump was shut down.
1996 to current the trim sender is not used for any oil transfer functons.
now the ECU/module needs a run signal taken from a pulser coil.
there are no sensors in the system.
there are 4 switchs.
3 in the engine oil tank and 1 in the remote.
SW1,SW2 and SW3 are in the engine tank. engine oil tank float up,SW1 is closed (grounded) commanding transfer pump off.
SW2 closed,float about midway, transfer pump is commanded on and will remain on UNTIL SW1 commands otherwise.
float down,SW3 closed, second transfer pump on command,RPM reduction command,audible alarm command and visual alarm on command.

if SWB remote tank, opens. no longer grounded.
yellow lamp is lit and automatic oil transfer is inhibited,remote tank has oil for about 2 manual engine tank refills.

myself I would monitor SW1 to insure its closeing.
if sw1 is closeing then your down to monitoring module voltage.

remember SW1 and SW2 spend all day going on,off,on,off.

once SW2 turns on the pump the only way it shuts down is by SW1 closeing or you dissconect battery voltage to the engine.

the replacement module eliminated the mercury switch and can be identified by a green/white wire going to a pulser coil terminal.

if the transfer pump fails to turn off then oil is pushed out of the vent into the air box or it pops the engine oil tank switch out of the tank, or both.
DO NOT get the idea to simply block off the vent tube.
seen that .

[Bullet1750]

Well this is starting to get to me, Spent 2 hours trying to work out why the pump was not stopping, voltage on the yellow and black wires was 12.8, the top switch was showing 7.6V across it before it closed and 0v when closed these signals were taken from the module side of the plug and still it would not stop. I showed several other sparky's just to make sure I was not going mad we could not get it to stop. The following day I pulled everything off checked it and put it back together, it works again switching on on the mid switch and off on the top........................BUT FOR HOW LONG???????????

[rodbolt17]

with the switch open the 7.6V is on the low side.
switch closed ov is correct.
but your going to have to monitor switch closed,white to black, WHEN it fails to turn off.
the engine tank switch is a signalman.
it signals the oil control module to turn the transfer pump on,off or turn on the low oil level alarms.
the oil control module is the switchyard master, it actually does the switching.
it spends all day listening to SWB,remote tank level.
and SW1 SW2 and SW3.
SWB simply tells the switchyard master if it has enough oil to actually make a transfer and keeps the tach green lamp on.
open it and yellow lamp is on and no automatic oil transfer.
SW1 is oil transfer off command,white to black closed.
SW2 is oil transfer pump on command,brown to black.
SW3 is oil transfer on second command,audible on,red lamp on and RPM reduction on.
once SW2 tells the switchyard master to turn on the transfer pump it remains on until either SW1 tells it to turn off or battery voltage is lost at the transfer pump.

[99yam40]

1984-1989 system used a seperatly mounted oil transfer pump control module.
module used a mercury switch to inhibit oil transfer when tilted.
module had a funny habit of turning on the transfer pump if module voltage dropped below about 9V.

myself I would monitor SW1 to insure its closeing.
if sw1 is closeing then your down to monitoring module voltage.

.

7.5 v is lower than 9v last time I looked

[rodbolt17]

the 7.5 he was monitoring was acrossed an open switch, once the switch closed you should see voltage acrossed the switch go to 0 v.
its the difference between an electrician and an electronics technician.
I am the latter, FC2 USN retired.
CIWS(NEC 1121) goolge that , is my primary naval enlisted code and I was working on harpoon missle systems as a secondary NEC.

[99yam40]

Rodbolt
But is the 7.5v something the module will see instead of 12 v while the switch is open and would that indicate low voltage at the module?


Bullet
Is the 7.5v still there when it is now functioning properly or is it back up to 12v?

[Bullet1750]

Rodbolt
But is the 7.5v something the module will see instead of 12 v while the switch is open and would that indicate low voltage at the module?


Bullet
Is the 7.5v still there when it is now functioning properly or is it back up to 12v?

The voltage across the 3 switches is still about 7.6volts and the voltage to the module (yellow and black wires) is 12.6volts and it is working fine ATM.

The thing that has me beat is that even when turning the key off and on several times and no signal to the start input the pump would always run and we could not get it to stop with the stop input. If it was not solid state I would have said the the relay contacts were stuck or welded. Then all of a sudden (half an hour later) when we reconnected everything after checking connections for the 100th time it worked fine. If it was a triac i could maybe understand it as they usually fail on but transisters usually work or they dont.

[Bullet1750]

7.5 v is lower than 9v last time I looked

The module voltage I think he was talking about is the supply which is on the yellow and black wires which was over 12VDC the 7.5 was the sink voltage across the reed switch which grounds to operate the input/signal

[99yam40]

Strange as the module has 12 v going in but it is only getting 7.5v to the switches.
May need to check to see if you have high resistance connector or is the 7.5v all that is coming out of module

[rodbolt17]

tyical digital operation voltage for switching is 5 volts.
Yamaha doesnt give the module to engine switch output voltage.
however with the switch OPEN any and all voltage will be shown acrossed the switch.
close the switch and you no longer have ANY potential difference therefore no voltage on the meter.
like I said.
engine running happily down da river.
transfer pump has key on 12V at the brown wire comes from the ign yellow via a splice just behind the 10 pin engine plug.

now the engine tank needs some juice.
SW2 closes,the module sees this as a transfer pump on command by grounding the module brown wire.
it reacts by closing the ground path,blue wire, from the transfer pump thus completeing the transfer pump ground path.

now the engine tank is full fat and happy.
SW1 closes sending a transfer pump off command by grounding the module white wire. module reacts by opening the transfer pump ground wre,blue to the pump, and the pump quits.
this cycle will repeat all day long.

however like I said, IF the module NEVER gets the pump off command it NEVER turns the transfer pump off.
so if the reed switch SW1 is failing the command isnt sent,if the internal module circuitry is failing it may not react to SW1, if module operating voltage is incorrect it cant react to SW1.

[99yam40]

I did not realize it used the 5v refrence ,you stated "with the switch open the 7.6V is on the low side.", so i was thinking it used the 12

So it sounds like his module is flaking out or the voltage to module just happens to be dropping below 9v when the problem is occurring, but reads fine when he was checking it.
At least that is what I get out of this.

Bullet1750

Did you check the module input voltage while you could not stop the pump and the SW1 was made up and the reading was 0v across it?
If so the I would think module is going.

[rodbolt17]

I NEVER said it should,would nor could have 5V.
I did say yamaha never gave us a spec to look for.
I did say TYPICAL digital logic uses 5V .
so just by reading 7.5V acrossed an open switch doesnt tell me much other than there is 7.5 volts of potential difference from point a(black wire) and point B (white wire) with the switch in the open position.

with the switch closed your basically measueing the potential difference between two points in a piece of wire, should be 0V.

if the switch is closing,verified with a voltmeter, while the pump still runs AND the module input voltage is still 12V then I would suspect a faulty oil control module.
thats why I actually own about 8 different meters both analog and digital.
occasionally I have to monitor more than one simple circuit.

REMEMBER IF the module never "sees" a pump off command it NEVER will that key cycle.
IF module battery voltage is not correct it MAY stay latched in the pump on command last commanded by SW2.