oxygen sensor help please?

[tgodiver]

I have a Yamaha 225 HP SWSII. I was running WOT at 5700 rpm, when all of a<br />sudden the engine lost power and die. It took like 10 mins. before it<br />restarted, but the engine never reach WOT, it ran like 3500 and lost all<br />power, and would sputter and die at idle.<br /><br />I checked the vacumn on the fuel pumps, compression checked, ignition wires were checked for sparks. All were ok.<br /><br />Could the oxygen sensor be the culprit? I took the sensor out and sprayed it with carboreutor clean. It was very black and oily. Would that work ok? Is there a way to check it?<br /><br />Could the oxysen sensor be the cause of the problem?

 

[vinney]

Re: oxygen sensor help please?

Yes there is a procedure to clean the o2 sensor. When I clean o2 sensor you need to change the cover gasket and change the spark plugs. I always check the low pressure fuel pumps for a bad diaphram. It will cause an over fueling if you have a bad diaphram. Check the cylinder heads with a heat gun to make sure its coming up to temp. If the thermostats havent been changed in two seasons change them too.

 

[DJ]

Re: oxygen sensor help please?

tgodiver,<br /><br />I'm going to make an assumption here. I assume that this engine is an EFI?<br /><br />If so, it sounds like your engine went into "limp" mode. Basically this means that the engine computer or ECM lost input from one or more sensors so it automatically substituted values to keep the engine running, albeit at a derated setting.<br /><br />I'm also going to assume that the processor now has stored codes that will take you to the offending area.

 

[Zachdog]

Re: oxygen sensor help please?

I had a similar problem with an '00 200 EFI and was told that Yamaha has acknowledged problems with the oxygen sensor. I had it replaced.

 

[seahorse5]

Re: oxygen sensor help please?

There is a reprint from a magazine about cleaning sensors at http://www.thebassguide.com/home/News/05-30-2002-01.htm

 

[highandry]

Re: oxygen sensor help please?

tgodiver... 02 sensor in no more than an 1 volt battery... cold will output no voltage from the 02 sensor... Hot will slow around 1 volt... if in questions about the 02 sensor.. just replace it.. but,if you want to play around. take the 02 out and connect and DC volt meter neg lead to the base of the sensor than connect the pos lead from the meter to the wire of the 02 sensor.. the add heat 800 to 1200 degrees.. <br /> my old grady I was running Yamaha 220 Special. a rare engine from Yamaha. very high hp output. but I could disconnect the ecm and bypass it.. this would let the engine run WOT... bypassing Coolant Sensor, very reving,Oil injection etc... <br /><br /> good luck <br /><br /> highandry