2005-2006 300 HPDI help

[tallimeca]

odds of weak spark on 3 are slim.
methinks your not using an actual spark tester.

the ECU can shut off various cylinders BASED on inputs from the shift position switchs OR it can misfire for RPM reduction.

it DOES not and CANNOT monitor did the spark actually jump the gap.\

all the firing of a cyl on YDS means is the ECU will or will not allow certain cylinders to spark.

you really really need to be carful who you get HPDI information from.

I had spark testers on all 6 cylinders. I wasn't sure if the added resistance would cause any issues but all cylinders were sparking during crank, as soon as it lit off, 2 and 3 stopped, which they are supposed to. I'm thinking the main cause is that forward sensing switch. The switch itself is functioning, but the tab on the micro switch was mangled. Went to dealer, they gave me a new switch (which turned out to be the wrong switch by part number) because when they looked it up they gave me a neutral switch, not a forward switch. But even engaging them manually we were seeing the problem. I'm guessing that the issue is the forward micro switch is substantially different than the neutral as far as the tab goes and when in forward, the switch is supposed to be engaged all the time and where it would hit it and go past it, that is where the issue is..... the ecu doesn't think it's in neutral or forward.

[rodbolt17]

WHAT?????
I don't know whether to say OMG or WTF.
it MUST think it is in some position.
and it will react to it.
YDS will show it.
if the switch is closed , on, the ECU (thinks) it is in N.
if the switch open, off, it (thinks) it is in gear.
why they placed two position switchs on the 06 an up models I have no clue.
theory holds it is for RPM control in reverse but like I said I personnaly don't know.

[rodbolt17]

most, not all, of the switchs are simple on/off.
most you can fake out the ECU by simply unplugging it,hook jumper leads across the pins and start the engine then remove the jumper.
the ECU should react by adding the 2 shut off cylinders.
this can be heard and observed on the tach.

I used this method on the phone to get a broken Z200 from Elizabeth city back to wanchese, maybe 20 miles.
got a 20 dollar tip .

if the switch works correctly you can see the 100-200 RPM momentary jump on the tach and the engine smooths out a bit when shifted into gear. it will miss when shifted to N.
don't even need the laptop just eyes ears and common sense.

[pstephens46]

most, not all, of the switchs are simple on/off.
most you can fake out the ECU by simply unplugging it,hook jumper leads across the pins and start the engine then remove the jumper.
the ECU should react by adding the 2 shut off cylinders.
this can be heard and observed on the tach.

I used this method on the phone to get a broken Z200 from Elizabeth city back to wanchese, maybe 20 miles.
got a 20 dollar tip .

if the switch works correctly you can see the 100-200 RPM momentary jump on the tach and the engine smooths out a bit when shifted into gear. it will miss when shifted to N.
don't even need the laptop just eyes ears and common sense.

Only $20 tip?!!!? Seatow would have charged him $1500 to tow without membership!

[tallimeca]

Switch

What I was questioning with the stator is with a multi circuit stator, there is usually a battery charge circuit, and a sustain circuit for operating efi components as you said. If the stator was faulty and there was insufficient voltage going through the circuits, the ecu readings could be off.

Just to be clear, we tested the switches with the fluke to made sure they functioned, we jumped the engine side of the harness to ensure there was a signal to bypass the switches, and we had the switches plugged in but dismounted from the bracket and were manually pushing the buttons in and out as we shifted the engine in and out of gear eliminating that the tabs were not contacting correctly.

My question on the 3 switch bracket on the 06 was what the sequence of the switches were. What I could not get 100 percent was on the forward switch, was the switch supposed to be engaged in forward for a continuous signal to the ecu, OR.... does the shifter go by the switch....contact it and send a momentary signal to the ecu..... then when taken out of gear, contact it again sending a momentary signal back to the ecu that it was coming out of gear, before it hits the neutral switch. So the mapping would be something like....

1)Neutral switch engaged- engine runs, 2 and 3 cut out, if rpm limit exceeded, additional cylinders dropped

2)Neutral switch disengaged , no forward switch signal- means engine was shifted in reverse, no signal in neutral or forward kicks in rpm limit in reverse

3)Neutral switch disengaged, forward switch engaged (******this is where I am not clear if it is supposed to stay closed, or a momentary closure)- ecu knows it is out of neutral and into gear, allow cylinders to fire and no rpm limit.

The issue with the cylinders not coming back on was happening no mater what we did with the switch when engaging them manually, which is why I though it was ecu/ignition control related issue.

[rodbolt17]

it is on or it is off.
no momentary.
some switchs have a resistor inside them.
without having the service manual in front of me to PROPERLY test the switch I cannot give you the switch values.
I can tell you the PROPER test procedure is in the manual.

[tallimeca]

thanks for all you help

Thanks for all the help and insight. I am not a marine tech. I come 25 years out of the Outdoor Power Equipment and construction equipment industry, as well as drag racing. I did what I could and it is in the hands of the dealer. I'm sure you can understand how frustrating it is and I just wanted to get as much insight as to what is or maybe the problem.

I'm expecting to find out from the dealer that forward switch was no good, we replaced it with the wrong switch they gave me and the new switch should be what takes care of the issue.

From an engineering standpoint, they shitty micro switch they use perform some awfull important functions

[boscoe99]

If Yamaha finds a bunch of extra parts laying around they will redesign a motor to use those parts.

Yamaha's motto seems to be "If three parts minimum are required to perform a job, we need to use at least four. Five would be better still."

Cables are wire harnesses.
Switches are on or off.
Wire colours are standardized, until they are not.
Colours change across connectors. Start with a red at one end and wind up with black at the other end of a circuit.
Coils sometimes are not coils.
No two models ever share the same features.
Up can be down and down can be up.
Same wire diagrams are used for different configuration motors.
Service manuals are never updated. Correcting a mistake is airing dirty laundry. Don't do that.

Pitty the poor diy'r or the Yamaha mechanic who has no theory of operation regarding what is supposed to do what, and when.