Help me with my oil tanks auto transfer issues...

[carboncow]

1991 225TXRP with a new digital tach. I have the placard that explains the lights.

The boat tank will not move oil to the engine tank on it's own when the engine tank is low and the boat tank is full.
Manual transfer does work
Oil sensor on boat tank has been tested and works
Oil sensor on engine tank has been tested and works (low buzzer & limp mode work)
Oil pump can be heard "spool up" when the ignition is first turned on.
As mentioned we can manually transfer oil with the switch

Tach shows boat tank is low regardless of actual level. Tach will show both tanks low.

Even knowing the switch tested as working we still tried a new sender (found one for $20 on ebay as new old stock.

Continuity has been checked on the wires from the sensor connection to the connector on the starboard side of the engine. From there...who knows as it seems to go into the CDI box.

What are we missing or what else can be tested to get the boat tank to move oil on it's own to the engine tank?

[rodbolt17]

what your missing is about 20ft of wirieng and a few splices on a stupidly old motor that one has failed.
an open circuit in a harness splice will LOOK exactly like an OPEN SWITCH to the ECU.
the 1990 -95 2.6L motors MUST have the correct input to the ECU on the TRIM sensor to operate normally.

dude you would be money in the bank to find a real tech, pay him/her and go play.
BEFORE you destroy your motor with your buddies help.

[carboncow]

We'll review the trim sensor again as it has some issues...but we thought we accounted for that today.

Any resource of what pins/colors are going into the ECU from the remote oil sensor?

We actually don't see any splices it what appears to be the factory loom (considered this today) and since the continuity is fine to the connector the issue of a bad wire seems to be in the last 12" to the ECU.

and yes...I can see this being the one issue that we wind up taking it to a tech over. Seems he would do better at wire tracing and/or understanding any failures/concerns in the black box.

[boscoe99]

You are not going to fail the motor if you don't let the main oil tank run dry. The alarm and RPM reduction mode should help prevent this from happening.

And you don't need a Yamaha mechanic to troubleshoot for you, if you are willing to learn. All Yamaha and other mechanics were ignorant of the system at one time and had to learn. But even with knowledge it will take some time and effort to find and fix the problem. And maybe some money.

More to follow. I am in Costa Rica and can't provide advice as easily as I normally can.

[carboncow]

Boscoe,

Thanks for the response and I look forward to any suggestions you have had. We have exhausted any solution we see for troubleshooting this tracing good wiring from the boat tank back to the connector on the loom...so a bit unsure what other solutions there are since we see no disturbed splices in the loom.

We are looking at a two good sensors, working pump and working warning buzzer/limp mode and about 6ft of good wire to the engine. What else?

[rodbolt17]

about 20 freaking feet of wire.
you do understand what T F a switch is??????
a broken wire will look JUST like an open switch to the ECU.
lose a ground,black wire, between the oil tank in the hull and the block.
guess freaking what.
the ECU sees it as SWB open and PROHIBITS automatic transfer.
the blk/red wire,almost the same thing however in the loom its spliced.
one side of the splice ccontinures to the ECU the other changes to green or green/white and heads to the tach.
lose any and the tach displays a yellow or center bar.
see how stupidly simple this system is.
its done 90% of the trouble shooting for you.
you have lost SWB's ground path or feed back path.

[carboncow]

I understand the Seloc manual leaves a bit to be desired but it does have a troubleshooting diagram and I get as far as the part where it tells you to jumper the brown to black wire at the PBS control unit...which I assume on mine it means to the black box. If states if this does not work to replace the control unit...yikes! (jumping it doesn't turn on the pump).

I obviously missed one set of wires going green/green-white going to the tach as everything appears (to me) to be to be going back to the ECU. We have not be able to trace the brown wire as it gets lost in the loom...appears to run over the power at the port side relays but continuity test says "no".

So based on your comment about green/green-white I'm obviously missing something here and this brown wire may be the concern.

We'll go back tot he drawing board tomorrow and reevaluate where it could be open as I would doubt the failure is in the black box...would you not agree?

Thanks for your time.

[boscoe99]

If you can wait until I get home next Tuesday I will provide you with the wire colours. In the meantime please send me a PM with your address. Got some information for you.

[rodbolt17]

you can jump that brown wire till the cows come home and milk all the bulls.

IF the ECU "sees" SWB open OR the trim signal is out of range it will NEVER turn on the transfer pump.

I have beat precision blend to death.

test continuity between a good engine ground and the remote tank connector black wire.

test continuity between the ECU and the remote tank black/red wire.
remember sometimes that wire color changes.
the splice in the harness sometimes changes from black red to green/black.

with the center bar lit on the tach it means a ground path has been lost.
is it between the splice and the tach?\
is it between the tank and the ECU?
if its between the remote tank and the ECU it will NEVER transfer automatically or by jumping the engine tank switch.

[carboncow]

Very good info. We are test running engine tonight and I will test remote tank per your process this weekend.


Questions:
I'm not sure what the SWB acronym is for, can you elaborate?
Should I unwrap the tape from the ECU bundle to confirm the color changes from the tank wire to the ECU connection to test? Not sure I can really see the inner wires on that big ECU connector anyways!

Trim Switch:
1. Trim switch (when moved over range) shows up and down properly on LCD
2. When in full up position the manual pump switch still works...is that correct?
3. Should it be tested in another way to confirm it's happy?

So from what you are stating the tach MUST Be hooked up for the system to auto pump oil from remote to engine? I understood the system to be independent of what the tach tells us...it's just the messenger. It actually requires to have a closed circuit for the pump to auto run!?!

Note that we have recently installed a new digital tach for this old engine. We have new wiring harnesses from the tach to the back as well as other connectors to tank and trim. These were selected by Andy at SIM parts and he called Yamaha to confirm hooking the dinosaur to the new digital. The engine tank does register on the tach (as well as warning buzzer on ignition) but I will confirm wiring continuity on the new dongle too to exclude any open wires.

PS. We know the over temp buzzer works but it doesn't register on the digital tach...so maybe there is a ground issue at work...or the wrong dongle.

[boscoe99]

SWB is the term for the switch in the remote oil tank. It provides a ground reference to the CDI/ECU which says there is sufficient oil in the remote tank for automatic oil transfer to occur. It also provides a ground reference to a Yamaha tachometer in which case a green light will illuminate or the right hand lcd bar will illuminate. Depends on the tachometer vintage. Early ones used lights, later ones use lcd's.

In a number of Yams the ground reference wire from the remote tank switch will be black with a red tracer. This wire runs primarily to the CDI/ECU but is tapped with another wire that runs to the tachometer.

Yam is all over the place with wire colours so a Yam service manual should be consulted. Even then, the data can be wrong. Yam apparently got tired when a motor model was completed and appears to have given up on data accuracy and completeness.

[boscoe99]

I see that your right hand lcd bar is missing. If the motor CDI is getting the same message it thinks the remote tank is low on oil. In which case the auto transfer function will be inhibited.

[carboncow]

Fixed. The black ground wire from the remote tank to the connection was in fact bad and we missed it the first time. All is well.

[rodbolt17]

see how simple this is???
the tach pretty much told me what was wrong.

[boscoe99]

Rodbolt comes through again.

Glad you found the problem.