250 HPDI Idling rought

[Eusebiorey]

I have a pair of 2003 250 HPDI that after i replace all filters, spark plugs and switched to Penzoil blend have started to faulded plugs after some 20 hours. The run WO close to 5K RPM no power ploblems during acceleration the only thing that they started to do is when first turn on they would bug down and shut off (a few times) until engine is warm up the idle RPM neutral bounces between 500 and 600. I am running ring free (prior owner never did) i have not CK O2 Sensor and i have not CK the oil link either.
Are there any step by step on how to do the above, also any other area that I should look into or should I run them a bit longer to see if the ring free finally cleans them out?

Thanks in advance

ER

 

[99yam40]

Re: 250 HPDI Idling rought

pick up a Yamaha service manual for that motor, it will give lots of step by step procedures for everything.
Or you can do a forum search for your problems and do a lot of reading to see what you can find.

 

[rodbolt]

Re: 250 HPDI Idling rought

check compression,check spark then test both lift pumps and both fuel rail pressures.
z250 doesnt have an O2 sensor.

 

[Eusebiorey]

Re: 250 HPDI Idling rought

pick up a Yamaha service manual for that motor, it will give lots of step by step procedures for everything.
Or you can do a forum search for your problems and do a lot of reading to see what you can find.

Thanks will do

 

[Eusebiorey]

Re: 250 HPDI Idling rought

check compression,check spark then test both lift pumps and both fuel rail pressures.
z250 doesnt have an O2 sensor.

Thanks Rodbolt
Compression CK OK
Whats the easiest way to CK for spark
ER