No check engine light when disconnecting O2 sensor - Bad fuel consumption

[danIstrate]

Hello everyone,

As the title says, I've been having bad fuel consumption for the past 6 months.

It all started in autumn / fall when I started seeing an increase in fuel consumption.
In the beginning, it was 1L more / 100km so it was not that bad. It peaked in December when I reached 11L/100km or 22mpg.

Until now I checked compression, valve clearances, connections, changed plugs to iridium and verified the gaps, checked coils cold and hot.

Last thing I did I measured the O2 sensor and it has showing no continuity. I changed the O2 sensor.

But there is a problem. If I disconnect the O2 sensor, no check engine light pops up.

I'm looking for an explanation. Does this mean there's something wrong with the ECU and it practically ignores / doesn't see the O2 sensor ?

Any advices on what to check related to not popping a check engine light when I disconnect the o2 sensor ?

Thank you!

 

[KillerwhaleTRX]

Could the ECU been flashed before to ignore the O2?
And now one or more injectors gone to shit and ooozing fuel into it.
Any dynos nearby?? a quick A/F measure should not cost an arm and a leg......
Have you checked the ECU on the bike, many put a sticker on em after flashed....

 

[danIstrate]

Update:

I took the connector out and did some riding, including city, highway and all out flooring it and still did not pull a code.

 

[danIstrate]

Could the ECU been flashed before to ignore the O2?
And now one or more injectors gone to shit and ooozing fuel into it.
Any dynos nearby?? a quick A/F measure should not cost an arm and a leg......
Have you checked the ECU on the bike, many put a sticker on em after flashed....

Sorry, your reply popped out after posting the comment.

This will most likely be the problem.

After it stops raining, I will pull the ECU and take it to someone to see if it's been flashed.

I am also betting on some injectors being clogged because I've been to Greece last summer and fueled in some shady gas stations, so suddenly, clogged injectors don't sound so far fetched.

I will keep you posted nonetheless.

As a last simptom that's new, yesterday it didn't start on first, second or third try.

It only started after cranking and giving it 50% throttle. So, in my opinion, it's pointing into some fueling direction.

We'll see.

 

[KillerwhaleTRX]

....also, when you get it started and rev it....
If it revs and hit the idle at a millisecond it should be on point......if it dips and then hits the idle it would be fat as fekk......other way if you rev and it hunts up there before idle it should be lean......