Yamaha 2002 TXRA150 HPDI/ TWO DEAD CYLINDERS

[casacabo]

I have two of these engines. One runs perfectly. The other has this problem:
there is no spark in two cylinders. All spark plugs are new. Just changed a coil and still doesn't have a spark. Any suggestions? Hope someone can help. Both engines have 250 hrs.
Thanks.

[rodbolt17]

which two cylinders.
in N it does not fire cylinders 2 and 3, a failed shift position switch can cause this as well.

[casacabo]

YYamaha 2002 TXRA150 HPDI still having problems

Update : as part of rule out of potential problem, mechanic switched over , from good motor to bad motor, the ECU and injector module control. This made no difference on the bad motor. Next the mechanic disconnected the neutral switch ( we can't find a part number for this) . Our understanding is that when this switch is working, it will "activate" the other two cylinders when you put the engine in gear. The thinking was that if the switch was disconnected, then the engine would run on 6 cylinders. Is this correct reasoning? Well... this did not happen... the two cylinders never fired. Any other ideas? We are now going to put the good motor parts back onto the good motor. Any more ideas for the bad motor?
We believe that there is something wrong with the switch so should we start with the purchase of that?
Please advise and thanks again. We are in Mexico, as is the boat, so I'm sure you understand our frustration when it comes to getting parts.
Hope to hear from you.

[rodbolt17]

cause you and the tech are, wait, cant say it.

its a stupid simple system.
I told you how it works.
you failed to say waht you did to dispute what I said.
yes I spend several weeks a year playing at exi importa marine in rio chico venezueala.
I understand.
why not simply test the switch?
its ON or OFF.
closed or open.
not rocket science.
however, if its open,ecu sees its in gear at start up, the ecu will lock that for the entire key on cycle.

its a dirt simple system, if you keep swapping parts your going to end up with two motors down and tech induced faults.

I do have a pass port and may travel

have your tech PM me, my wife is venezuelan and will translate from spanish.

[casacabo]

Yamaha 2002 LZ150 TXRA not working

When power is applied to the neutral switch it opens and closes. Our next idea is to find a guy with an engine diagnostic analyzer. Any other ideas?

[rodbolt17]

its NOT a neutral switch.
get that out of your head.
there is a shift POSITION switch, when its open it allows 6 cylinder operation, when closed, its 4 cylinder operation below about 1400 RPM and 2 cylinder operation above about 1400 RPM.
if the switch is shorted or stuck closed you will always heve 4 or 2 cylinders operating.
if open and it gets a crank signal it locks max engine speed to about 1500 RPM.
if the ECU sees a crank signal AND an ingear,shift position open, signal it defaults and limits engine speed for the duration of that key on cycle.
no codes though.
the neutral switch is located in the control box and simply allows the engine to crank over or not.
has NOTHING to do with engine operation.
every sensor and switch on that engine can be tested with a digital multimeter.
you can also use the diagnostic test lamp or the laptop.

[200090tlry]

Just send ol rod a plane ticket and car waiting and some iced up servasa

Little marlin fishing good break. Hey rod do you like skiing? I see a vacation comming to Utah. If the techs touch the motor maybe a simple ground wire for coils? I would look around under hood

[rodbolt17]

dont ski, dont fish much anymore.
hate cold.
the HPDI ign is a TCI.
Transistor Controled Ignition.
means we hit the coil primary with 12V and the ground path is transitor switched on and off in the ECU.
think of the 6 switching transistors as points and the six pulser coils as the cam lobes operating the points.
we still dont know which two cylinders are not fireing nor how it was determined.
we do know that this engine is in a third world area.
while having never worked in mexico I have worked with a tech in Venezuela.
trust me, training is spotty.
you think its bad in the US, try another country south of here.