Solution: K9 GSXR Loosing power, then kicking back in.

[Paraletic]

Ok firstly, I am not asking how to fix my bike, i've already done that. I just want to put this up here as a reference for others with the same problem. Happy to provide more information if you need.

Bike: 2009 GSXR 600, Yoshi R-55 slipon.

Problem: Bike suddenly losing power momentarily, then power returning suddenly as throttle is turned on.

When: When cruising at less than 8000 rpm, in any gear, at no specific speed.

Cause: faulty Oxygen sensor.

Description of problem:

The bike appeared fine while the computer was in open loop mode. However once a ‘cruise’ mode was established, the only time the ecu will go to closed loop (using feedback from the O2 sensor to reduce fuel consumption). Cruise mode is established by certain parameters, engine speed (in this case 8000 rpm) and engine load (usually about 20 – 10 “Hg).

So once this was established, the faulty sensor would indicate over fuelling thus cutting/reducing fuel injector duration. As power dropped, load increased to above 10 ”Hg, sending the computer to open loop, and the bike would run nicely again on the load matrix. This resulted in a large kick making riding in the lower gears difficult and unnerving.

And yes Suzuki knows about the problem and the fix, however they won’t tell you this. All the dealers have a memo about it.

The fix: Replace O2 sensor with a New/updated one, or like I have done use an O2 Eliminator.

This information is also the concensus of what has happened on the gixxer.com and other forums, just wanted to save you reading 15+pages of nothing to find the answer, as it seems a common ploblem from K7 to K9.

[benlikesbikes]

I don't have a GSXR but good work on sharing the info!

[Para045]

just wanted to save you reading 15+pages of nothing to find the answer,

So it's a lot like PSB then

[g0zer]

what is the O2 eliminator? is it just a resistor to trick the ECU into thinking it has a sensor? I am wondering how the O2 eliminator manages the closed loop ECU feature?

[Stoneville]

mmmm thanks, sounds like the same issue I have with my 07 750 and 08 1000, I find I have to knock them back a gear when trying to maintain a set speed, worse when going down hill, might look into it and see if it sorts the problem

[Paraletic]

what is the O2 eliminator? is it just a resistor to trick the ECU into thinking it has a sensor? I am wondering how the O2 eliminator manages the closed loop ECU feature?

i believe so. i do not know what it is sending to the ecm, i only like it as it stops the FI light from flashing.

mmmm thanks, sounds like the same issue I have with my 07 750 and 08 1000, I find I have to knock them back a gear when trying to maintain a set speed, worse when going down hill, might look into it and see if it sorts the problem

easy way to find if it is the same thing, find out how many revs the limit for closed loop (considering my 600 is below 8000 rpm making it half of full rpm of 16000) try riding above and below the mid piont of your rev range and see how she goes.
or disconnect your lambada sensor and see if it goes away.

[Max Power]

Did your bike throw up any warning lights?? or just act homo? Ive got what i think is the same issue.. suzuki mechanic reckons it could be something else...

[Sookie]

Any idea of this would affect a k9 750?

[thro]

One would query why the dealer doesn't plug into the ECU (or do whatever magic sequence to get the diagnostics out of engine/FI light flashes) and download the fault codes which would have reported this....

[Max Power]

Mmm hope so. i couldnt leave the bike with them, but they picked up an issue, and will call suzuki to hear what they have to say. If not i will have to leave the bike with them to run diagnostics while running the bike on the dyno, and see whatelse is going on

[Commander Keen]

One would query why the dealer doesn't plug into the ECU (or do whatever magic sequence to get the diagnostics out of engine/FI light flashes) and download the fault codes which would have reported this....

It doesn't sound like it would throw up a fault code, more like bad programming to put the bike in 'cruise' mode in the first place

[thro]

If the sensor is faulty (which was the diagnosis, and a replacement sensor fixes it), it should throw a code - or at the very least show the ECU running in closed-loop when it shouldn't under diagnostics.

If the programming was faulty, it wouldn't be fixed by a replacement of the sensor or fooling the ecu to stay open.



edit:
OP - any idea of the faulty part number? I would wager it would have been used in all GSX-Rs (and possibly other suzukis or even other bikes) between year X and year Y. O2 sensors are a generic part likely supplied by DENSO or one of the other jap sensor / efi component suppliers.

[henrys]

The O2 eliminator is a resistor and a capacitor, still pretty simple.
For those interested in more see $4.50 DIY O2 Sensor MIL Eliminators but note these folk are using the device to trick an ECU monitoring catalytic converters. For those who are happy to eliminate their closed-loop O2 sensor rather than replace it, hence losing the "cruise mode" and economy, the same eliminator should satisfy the ECU.

Me? I don't have to worry about all this stuff as my newest vehicle is a 1984

[Max Power]

Ah the part number is floating around somewhere. But yeah the same sensor fits most of the + 07 GSXRs from what i recall.

Suzuki just called and confirmed it was the O2 sensor being homo. And will replace under warranty (even tho its an 09. Still got a couple months warranty remaining )

They've ordered one it should be here by the end of the week!

Simple

[TheBrad]

You would hope they reengineered it, see it all the time in cars, the part is a common fault, it dies so you replace it with the exact same item, fail. Keep it in mind though.