150hpdi question for ken

[slim]

hey ken. friend of mine has a 150hpdi that has a rpm fluctuation of about 3-4 hundred around 5000rpm. could the o2 sensor have anything to do with it?

[Ken]

Michael,
Sure could - take a look at this procedure on cleaning the O2 sensor:

http://www.boatsetup.com/O2sensor.pdf

Also, low pressure mechanical fuel pumps could be suspect, as well as the filter in the vapor separator tank.
Good luck [img]smile.gif[/img] ,
Ken K

[jb123]

slim,im curious, as a yamaha technician for 13 yrs, why are you asking questions here ?

[Ken]

Hey jb - if he is as old as I am, maybe he has forgotten most of what he has learned [img]smile.gif[/img] [img]smile.gif[/img] .
Ken K

[slim]

hi all. no actually i was just wondering how good you all are. actually the o2 sensor has nothing to do with any problem over 1500rpm on an hpdi. all the signals are mapped into the cdi as constant values. after 1500rpms it refers back to the mapping built in the cdi and the signal from the o2 sensor is not used. just some info for yall. quite a few times i even showed the yamaha service rep up. but im not trying to brag. any serious problems you have, just ask. ill be more then happy to help.

[Ken]

Hey slim,
Let me see if I have this correct - you post a "trick" question on this forum to see "how good we are" ?
Are you planning on buying out boats.net, or maybe start paying "good" forum members for their service?
I don't know about anyone else on this forum (besides the boats.net guy), but I don't get payed a dime for the time I spend trying to help others. I don't pretend to be an "expert" on Yamaha outboards, and I have stated that many times. I'm just another Yamaha owner who tries to help others. All that I have learned is from working on my own outboard and from posts from other forum members on this and other forums.
When a question is asked that I am not very familiar with, I wait for other more qualified members, like jb, Hamfisted and the boats.net guy, who by the way is the only "certified mechanic" on this fourm, to answer. If no answer if forth coming, I try to help the member and give an opinion as best I can.
If you take the time to read back over my posts, you will find I have helped a lot of Yamaha owners fix their problems. And, yes, a lot of it has been by the "seat-of-my-pants" advice. But at least I was trying to help.
I, for one, welcome you to the forum as I do anyone who wants to contribute in a "productive and courteous" manner. But keep the "trick" questions for someone else, and another forum.
Ken K

[Hamfisted]

This has to be a *****.

I would believe "Slim" is a 13 year old, but not a 13 year Yamaha tech. I think some kid got ahold of his dad's computer...

The O2 sensor is used on the EFI and small-block HPDI throughout the rpm range as one of many inputs to the ECU to let it know how close to the perfect air/fuel ratio it is running. The "MAP" is simply the ECU's target "perfect" A/F ratio for a given load and rpm. Absent the O2 sensor input the ECU will revert to default settings, generally richer than optimal targets, with increased emissions and reduce efficiency.
On the big block HPDI's they did away with the O2 sensor and just depend on the other sensors and a more powerful ECU to keep the A/F near perfect.


-Mike

[slim]

hello. do you think a 13 year old would know what a o2 sensor even is or how it works? if you ask you service rep if the o2 sensor signal is used after 1500 rpms on a hpdi, he would say no. if he says yes, you need to go tell him to go back and talk to mr shoemake. he teaches the yamaha service school in kennasaw geeogia cause they are wrong. i challange anyone to any problem on any yamaha. ask any yamaha rta and they will tell you if it hasnt happened on the mississippi or louisiana coast, it hasnt happened at all. as for the o2 sensor on the big block(3.3l) just like the 2.6, it is mapped into the cdi and is not needed. do you really think they would take it off if it wasnt needed when they had a patent on it in the boating industry? i just wish some of you really knew what you were talking about cause just like some dealers, the customer usually has no idea what the problem is and he believes in what he was told at the dealership and has no idea what the real problem is. he owns the boat and he should know the truth. if you dont know the truth then tell him you dont know but you will do your best to find out what the problem is. dont try this and try that and tell him i think its fixed but go try it and let us know. fix it the first time and make him happy. this is one thing my last employer didnt do and that is not the way a good and respectable business is run. if i was a 13 year old, would i know that a hpdi's ignition system is a tci and not a cdi ignitin system and would i know that that stands for transistor con*****ed ignition and that it requires battery voltage to operate opposed to a cdi ignition system that does not? what else should a 13 year old know?