2005 Yamaha 200hp HPDI

[YamahaHPDI]

Good afternoon,


I am having an issue with my HPDI motor (LZ200XTR)
When attempting to get the motor on plane, I am only able to get to a maximum of 2800 RPM's. It is also idling rough at 500 rpm. (After replacing spark plugs, it idles at good at 800. After parking and then restarting , it idles rough at 500rpm)

So far, we have replaced:
all new fuel lines
New pump bulb
Every filter including the mystery filters
Swapped VST from a known working parts motor
Sent the injectors off for servicing/ cleaning
New neutral position sensor
New throttle cables
Old fuel was removed and replaced with new non ethanol fuel with added ring free
New plugs
Swapped ECU from parts motor
Replaced low pressure fuel pumps

This motor was purchased from a person who had the same problem and finally just got sick of working on it.
If anyone has any more suggestions for us, it would be greatly appreciated.

P.S I am sure there are more parts that were replaced/ swapped that I am forgetting.

 

[boscoe99]

What is the high pressure fuel pump reading?

 

[YamahaHPDI]

What is the high pressure fuel pump reading?

Between 690 and 710 psi while at WOT running at 2800 rpm

 

[YamahaHPDI]

Any other suggestions? I'm kind of at a loss on whats next to check

 

[99yam40]

are all cylinders getting spark and fuel when problem shows up?
not all cylinders fire is the motor thinks it is in neutral.

find the YDS and hook the motor up to a lap top

 

[YamahaHPDI]

are all cylinders getting spark and fuel when problem shows up?
not all cylinders fire is the motor thinks it is in neutral.

find the YDS and hook the motor up to a lap top

While in neutral, it is running on 4 cylinders as it should.
When in forward gear, it is running on all 6 cylinders, at least that is what the YDS is showing.
I did notice on the YDS while on the muffs, the TPS is showing a little high. Would that have any effect on it ?

I have triple checked the neutral position switch after replacing it. It is signalling correctly on the YDS.

 

[99yam40]

just because yds says it wants all cylinders to fire does not mean they are.
you need to see if all are getting spark and fuel some how.
spark should be easy, with a timing light or spark tester
not sure how to ckeck fuel
maybe monitor the injector pulsing

 

[YamahaHPDI]

just because yds says it wants all cylinders to fire does not mean they are.
you need to see if all are getting spark and fuel some how

Any suggestions how I would do that?