150 HPDI loss of cylinder #3

[Holy Smoke]

Help

I have a pair of 150 hpdi's with 610 hours and until last week would turn 5700rpms wot

Now the Starboard motor only turns 5000 and the port 5500

The motors run great up to wot and I am missing the 700 rpms on the starbord motor and 200 rpms off port. I assume the 200rpm missing on the port motor is becasue the starboard motor is not putting out full power. I have no bucking, surging shaking or anything else funny going on

All fuel filters changed 6 months ago including the hight pressure pump filters.

Since it was time to change the plugs I replaced all the plugs in both motors (no change in max rpm)

11 out of 12 looked perfect the odd plug was number 3 on the Starboard motor. That plug had perfect burn on 1/2 of the insulator and the other half looked bright white and wet like it had been fuel washed. I am thinking bad coil,plug cap so:

I tested the coil and cap on the #3 cylinder and both are in spec, YDS shows no codes and everything is in spec.


I tested the spark via YDS and it looked the same as the cylinder next to it. I did not use a spark tester I just did a visual look


I swapped the coil and cap from cylinder 1 to 3 and no change cylinder 3 still does not produce power.

I pulled the plug wire from cylinder 3 and the boat ran the same meaning cylinder 3 is my issue.

I tested the injector via YDS and it fired fine.

I pulled the injector on number 3 and had it tested and it was perfect.

Here is the plug from number 3

The other side of the same plug


The other 11 plugs looked like this:



YDS numbers at idle

Monitor Item Result Unit
Engine speed 775 r/min
Fuel pressure (5.0±0.8) 4.99 MPa
Fuel pressure (725±116) 723.82 psi
Atmospheric pressure 997 HPa
Atmospheric pressure 29.5 inHg
Ignition timing BTDC 1 deg
Battery voltage (12-16) 13.99 V
Oxygen sensor voltage (0-1.0) 0.87 V
TPS voltage (0.5-4.5) 0.58 V
Throttle valve opening (0-90) 1.7 deg
Fuel injection duration 1.08 ms

At WOT

Monitor Item (DATA)ResultUnit
Engine speed 4950r/min
Fuel pressure (5.0±0.8 ) 5.26MPa
Fuel pressure (725±116) 768.23psi
Atmospheric pressure 1011.8HPa
Atmospheric pressure 30inHg
Ignition timingBTDC 16deg
Battery voltage (12-16) 13.84V
Oxygen sensor voltage (0-1.0) 0.9
VTPS voltage (0.5-4.5) 4.17V
Throttle valve opening (0-90) 77.1deg
Fuel injection duration 1.48ms

VST fuel pressure at WOT 49 psi steady.

I did notice the port motor idles about 100 rpm less then this motor which seems to show something amiss


ECU maybe? I am at the end of my ability at this point.

[Holy Smoke]

Anyone have any ideas.

Going to put the motor back together and double check all electrical contacts, if that does not work then its off to a Master Tech

[99yam40]

Rodbolt17 might have some info for you if he sees this thread,
But I have no clue

[Sequoiha]

I would say check your shift cut out switch, on an hpdi it cuts 2 and 3 in neutral, maybe it is vibrating at high rpm and causing the miss fire..

[rodbolt17]

shift switch can be monitored via YDS while running.
it will also toss a code .
notice the O2 sensor readings?
I would look at the lift pumps,injectors and injector driver.
the injector test function does not use the same circuits as when running.

[Holy Smoke]

shift switch can be monitored via YDS while running.
it will also toss a code .
notice the O2 sensor readings?
I would look at the lift pumps,injectors and injector driver.
the injector test function does not use the same circuits as when running.

Rodbolt

Did you you get my private message?

[rodbolt17]

nope
I don't do much with PM,s and NO technical discussions via PM.

[Holy Smoke]

nope
I don't do much with PM,s and NO technical discussions via PM.

I was just asking who you work for so I could
Bring my boat to your shop

[99yam40]

This is what he has posted before
http://www.yamahaoutboardparts.com/86457-post10.html

[rodbolt17]

I work at Joe's marine in Wanchese NC.

to get there you drive until you hit the end of the earth and take a right.

my GPS wont even take me to the shop.

you can also use the dealer locator function on the Yamaha web site. look for master techs in the 27981 zip code.

[Holy Smoke]

I should be dropping it off in a couple of weeks

[Holy Smoke]

I am going to swap injector drivers and if the problem moves good for me and if it stays ....Mr Rodbolt gets my boat in a few weeks.

[rodbolt17]

if it moves, bad for you.
that injector driver isn't cheap.

[Holy Smoke]

shift switch can be monitored via YDS while running.
it will also toss a code .
notice the O2 sensor readings?
I would look at the lift pumps,injectors and injector driver.
the injector test function does not use the same circuits as when running.

I have been trying to reasearch the o2 sensor readings comment and I cannot
find any reference, can you tell me what your thinking is on that? I am
curiuos to know and try to understand my motors better.

[99yam40]

I believe it is reading too high at idle and should be moving (not a steady reading) indicating rich fuel maybe.
Should not affect HPDI motor above 1500 RPM from what I have read.
Have you check on the lift pumps ?

But I do not know what they should be reading
See if you can do a search on HPDI O2 reading to see if brings up anything