Yamaha 150 HPDI no spark on 3 cylinder 1,3,5

[cinikal1]

Hello all, A friend of mine brought me his boat to do some work on it. Someone prior to me left him High and dry with an engine partly disassembled due to having an exhaust leak on the exhaust guide. The symptoms he had at the time was misfiring. I received the motor with the electronics removed and several bolts broken in the exhaust guide. And he abandoned the project half way thru.

I got it all put back together with a new exhaust guide.I changed all the filters in the fuel system (VST, Mystery, all), i have checked the fuel pressures, Brand new plugs and I fired it up. I am misfiring #'s 1,3, and 5 cylinders no spark at all, even in gear. I measured the ohms of each coil and they read fine. Owner says that that was how it was running before they started taking it apart. The exhaust guide definitely needed to be replaced as it had a big hole that was leaking back into the cowling leading them to believe it was causing the misfire, But it is still doing the same exact thing according to the owner. I can pull those wires off the plugs and there is no spark coming from them.

Any advice on what to check next? Thank you
Chuck

[99yam40]

another thread without model # for motor

I was thinking those HPDI motors idled without 2 cylinders and if throttle was increased while in neutral is dropped more cylinders
1,3, &5 are all on one bank, I did not think they would drop cylinders on just one side

[boscoe99]

another thread without model # for motor

I was thinking those HPDI motors idled without 2 cylinders and if throttle was increased while in neutral is dropped more cylinders
1,3, &5 are all on one bank, I did not think they would drop cylinders on just one side

Par for the course. Must be top secret information.

[99yam40]

Par for the course. Must be top secret information.

Boscoe what are your thoughts on killing spark one bank and maybe in injectors on one bank.
what could do that?

[boscoe99]

Check the ground from the cylinder head to the block. Check to ensure that battery power is on all of the injectors.
zinj.png

[boscoe99]

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[cinikal1]

I am so sorry! I was confused and it is Cylinders 2 - 3 - 6! I am sorry for the misinformation. But at Idle and in Gear I have no 2-3-6 spark. Just to be clear in case I am making another error. It is looking at the engine on the left it is the top and bottom cylinders and on the right it is the center cylinder. It is an LZ150TXRB

[99yam40]

I am so sorry! I was confused and it is Cylinders 2 - 3 - 6! I am sorry for the misinformation. But at Idle and in Gear I have no 2-3-6 spark. Just to be clear in case I am making another error. It is looking at the engine on the left it is the top and bottom cylinders and on the right it is the center cylinder. It is an LZ150TXRB

which left is that?
the one facing the motor from behind or the one facing it from inside the boat

[TownsendsFJR1300]

which left is that?
the one facing the motor from behind or the one facing it from inside the boat

Port or star board and from top to bottom might be easier...

.

[cinikal1]

I again am sorry! It is Port 2 and 6 and starboard 3 are not firing even if the idle switch is not engaged!

[cinikal1]

Port top and bottom, Starboard center, Have no Spark coming out of the wires. Idle or in drive. Any Idea where to start? I have Multi-meters and O-scopes if any one can tell me where to look! Thank you!

[boscoe99]

Is there battery voltage on the R/Y wires to the coils?

Is there continuity in the other wires back to the ECU? Are those wires not shorted to a ground?

Cylinder numbers are based on the motor being viewed from behind. Left is left and right is right.

2 1
4 3
6 5

[cinikal1]

Yes there is battery voltage on the red and yellow wires. The other wires(Black with ? stripe) show no signs of short to ground!

[cinikal1]

What would be the next logical step to check? As I am not fluent in these motors... should I swap the computer part from one to the other? There are 2 motors on this boat. I have an o-scope if that helps me diagnose the problem. Can I see if the computer is sending the signal to spark with a digital scope?

[99yam40]

from what I understand The Ecu should make and break the ground to create spark.
hopefully Boscoe will chime in with some help