Yamaha '91 115HP 2 strk oil transfer problem.

[boscoe99]

And folks think being a mechanic is an easy job.

Why didn't the ECU/CDI just set a code that tells exactly what wire(s), and where, needed to be fixed?

[Kartoffel]

I can't believe this is kicking my a** so much. I felt I really understood it and had isolated the bad ground wire as the issue. Fixed that and it all went to hell.


So it seems I still have 2 problems

1. still showing yellow on tach (even though signals seem normal) As I originally said, I can't be certain I ever had a green light. This is a 1971 boat and the control wiring is a mess, but seems to all be connected.

2. No emergency switch operation or Oil level buzzer, this really concerns me as the oil buzzer has saved me twice before (4 years ago it was a bad pump). Is it possible I burned up the ECU testing pins?

You guys have been super helpful and obviously know your stuff, is there anything I can do to run this to ground (so to speak)? pictures?

Engine runs fine otherwise, I'm guessing as long as I have oil in the main tank I'm safe to run it, right?

[Kartoffel]

PROBLEM SOLVED: Here is the solution for posterity.

Ok after a meal, some alcohol and sleep I figured it out.

All my continuity checks were correct but I figured out after I spliced the repair cable the oil system was not tied into the signal ground any more. This connection was buried in the harness. This explains why the alarm and pump stopped. They needed that ground to work (I guess).

So I figured out the ground ref reaches the tach through the trim sender and by putting a jumper between the trim ground cable and oil ground harness at the umbilical entrance to the engine, yahtzee! everything works.

I'm guessing that this is a good permanent fix as well? I will build up a small water proof cable X-junction and plug it all in at the engine and I should be good, right?

Jeff

[rodbolt17]

that last post was so confusing that now I know who writes the instructions on Wal-Mart furniture.
folks precision blernd is so stupidly simple I don't know why it kicks techs butt.
yet it does.

4 switches (on or freaking OFF just like a light switch) a pump and wireing to it.
if rigged with the correct Yamaha gauges most the troubleshooting can be done with a simple observation.

over the years there have been a few changes,almost insignificant yet if a tech doesn't understand and pay attention they will chase farts for hours.

[boscoe99]

that last post was so confusing that now I know who writes the instructions on Wal-Mart furniture.

Yes, but they beat Yamaha instructions, which for all intents and purposes don't even exist.

Hey, I have an idea for a service manual. Let's take the parts catalog and throw some torque values in it. Maybe a confusing or incorrect specification or two. Yes, that will do it.

Let's call torque ft-lbs instead of using the correct term.

Oh, Yamaha already beat me to it.

[Kartoffel]

For the record, what wasn't obvious to me was not just to check continuity between pins in the harness and to the back of the tachometer but to check continuity on the black wire to a known good signal ground. Not obvious because that signal ground enters the back of the tachometer in a different connector from the oil light signals.

In my case the most accessible good signal ground was the connection from the trim sender.

Here's hoping it all helps someone else down the road.

[boscoe99]

If I were you I would verify that the oil system transfers oil as it is supposed to, that the oil status lights illuminate when they are supposed to, and that the thermoswitches sound the alarm as they are supposed to.

[rodbolt17]

if you want another example, look at the shift actuator voltage specs on an fv8 300/350.
sometimes the jinglish just don't work.

back to the oil issue.
the tach controls nothing.
the oil control module,in this case inside the ecu, controls most everything.
at key on the transfer pump has 12v on the brown wire.
there is a spice in the engine harness that can fail.
based on ground signals from the engine tank the ground path for the transfer pump is applied or removed.
however this entire time the control unit is looking at the REMOTE tank level.
if the remote switch is open OR a blk or blk/red wire is broken the tach loses the ground signal and the yellow lamp illuminates(center).
the blk/red is also spliced in the engine harness and that's where the green or green/white to the tach comes from.
like I said its a dirt simple system but several things are happening at once and if you miss it it can drive you nuts.

but all the tach is looking for is the low signal(ground) on the green/white wire . if its there you get a green lamp or far right bar, if its not you get a yellow or center bar.
if the ECU sees a loss of this ground it prohibits auto transfer.

[portauki]

Unrelated but it worked for me

I had the same problem on my 1994 250Vx76. Drove me nuts, spent almost $1200 on dealer repairs who told me it was the wiring harness, the float, the computer etc....I finally went to the dealer who i bought the engine from back in 94 and asked me if I had changed the filter on the remote tank. I said, "what filter?". I bought it for $12 replaced it and everything has been fine since.
I don't know if this is related, but I was in the same predicament as you.

[boscoe99]

I had the same problem on my 1994 250Vx76. Drove me nuts, spent almost $1200 on dealer repairs who told me it was the wiring harness, the float, the computer etc....I finally went to the dealer who i bought the engine from back in 94 and asked me if I had changed the filter on the remote tank. I said, "what filter?". I bought it for $12 replaced it and everything has been fine since.
I don't know if this is related, but I was in the same predicament as you.

Wouldn't it have been nice if Yamaha had published a fault tree in the service manual that suggested that this be one of the first things to check?

The manuals are so crappy that even the dealer mechanics don't know what to check for, and when. Apparently they like to throw parts at a problem since the customer is footing the bill. Thanks Mr. Customer for the blank check.

Pity the poor user has no advice whatsoever to go on. He fumbles around on his own having no idea how motor systems function. He then comes to forums such as this one and then gets three, four or more contradictory suggestions as to what to do.

[rodbolt17]

they DO publish a fault tree.
yet most techs cannot wrap their heads around several things going on at once.
its s stupidly simple system with 4 switchs.
SW1 and SW2 simply bounce on and off all day long until something happens.
then SWB or SW3 get involved.
if SWB opens the yellow lamp is illuminated to alert the operator that the remote tank is low and the oil control prohibits automatic transfer.
I mean, why bother the dang tank is empty.
however there is enough oil for about 2 manual transfers.
that's about the time SW3 gets involved.
as most operators don't pay attention .
the yellow lamp or center bar illuminates, about 15 min later the red lamp or far left bar is on and so is the alarm.
and then we toss in the most neglected feature.
that dang remote tank filter.

[boscoe99]

they DO publish a fault tree. Yes, hidden to most, buried in an MTG. And, it is a crappy document, at best.
yet most techs cannot wrap their heads around several things going on at once. Because of Yamaha's lack of adequate SM and training information.
its s stupidly simple system with 4 switchs. Stupid once the system is understood. Complex if one does not understand the system. Where is the engine specific theory of operation in the SM? One won't find any.
SW1 and SW2 simply bounce on and off all day long until something happens. Where is this explained in a SM? It isn't.
then SWB or SW3 get involved.
if SWB opens the yellow lamp (not all tachometers use a yellow lamp) is illuminated to alert the operator that the remote tank is low and the oil control prohibits automatic transfer.
I mean, why bother the dang tank is empty.
however there is enough oil for about 2 manual transfers.
that's about the time SW3 gets involved.
as most operators don't pay attention .
the yellow lamp or center bar illuminates, about 15 min later the red lamp or far left bar is on and so is the alarm.
and then we toss in the most neglected feature.
that dang remote tank filter. Where does Yamaha show this as a preventative maintenance item? No where that I can find it.

It might appear that Yamaha's data is intended for use by the Master Mechanic or two (maybe the ten of them that understand the PBS system) and then leave everyone else hanging. Guess that it is job security for the Yamaha USA folks that man the dealer support line. How would you like to be the man that gets ten calls a day from dealers asking for help trouble shooting a PBS issue? Incredibly inefficient, frustrating for the dealer man and boring for the Yamaha man (assuming the Yam man understands the system as some don't).

[boscoe99]

Here is the sum total of all information related to PBS in an HPDI model. No system description, no theory of operation, no trouble shooting guide, no mention of tachometer status lights, etc. Pretty pathetic IMO.