Need experts opinion - euro WRX, AIS, O2 and FA mixture

Hi everyone!
I need to solve last one question prior to making final desition about AIS removal.
Look, in euro models (black frame) we have O2 sensor near EXUP and fresh air from AIS before it. That means, ECU "knows" about extra O2 in exhaust system and makes FA mixture regarding this "extra".
If I will just remove AIS, thus this "extra" O2 ECU will prepare mixture to fit factory mapping by adding less fuel to engine, and run lean that is very bad.

So basicly in this situation I should consider buying a some PowerCommander, right?

It seems that this didn't apply to Americas model whitch not have O2 sesor by default and can remove AIS with no impact to ECU and FA mixture...
Please correct me if I am wrong.

Thanx!

I think you're right, but only based on logic. I don't really know. AIS systems on autos vary by engine temp, ie; more air on cold start to burn rich start mix. It would be real interesting to know the exact programming differences between the sensor and non-sensor equipped bikes. It may be that the CO settings available through the instrument diagnostics and adjustment mode were built into the bike just for this purpose. If so, you could simply adjust settings there.

But... I'm guessing others will suggest an aftermarket FI controller to best tweek the fueling for the lean spots programmed in to pass emissions test parameters.

Just Bob wrote:

AIS systems on autos vary by engine temp, ie; more air on cold start to burn rich start mix.

In general its not so simple. I will googleit how O2 sensor work to understand this internals.

I just took away my O2 sensor when I installed the new exhaust together with the FMF programmer.
Have done some adjustments to the CO settings in the dash and together with some adjustments in the FMF box my bike works just fine.
Checked the sparkplug and it has a nice light brownish colour.
No dips in powerband and no exhaust bangs when i let off throttle....

What i heard the 02 sensor and AIS together with the cat is some enviro thing for pollution when idling??

If my bike brakes down I have only myselve to blame but my sence and feeling is that the bike is running just fine wihtout all those parts.......

mr-cave wrote:

What i heard the 02 sensor and AIS together with the cat is some enviro thing for pollution when idling??

You're absolutely right, AIS+O2 sensor = good FA mixture for Catalytic converter, not for perfect engine work. From info I found goes that all this components works together only for one purpose - make 14.7 Air-Fuel mixture in all range of engine for CAT, not only idle IMHO. The last hope is that response from O2 sensor don't used in ECU or have not much impact to it and USA models almost proves this assumption.

May be AIS works with O2 sensor totally separated from engine...

To prove my theory I just need to put some external lambda, disconnect AIS and measure AF number (should be between 12.5 to 13.3)...

Good article with pictures:
http://www.12v.org/engine/index.php?section=hw&sm=2nd

Today I got some info from Service manual:

Quote :

FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator is installed in
the fuel rail, and maintains the fuel pressure that is applied to the fuel injector at 245–255 kPa
(34.8–36.3 psi) (2.45–2.55 kg/cm2). The fuel injector is operated due to signals from the ECU, and in-
jects fuel into the intake manifold. Since fuel is supplied only for the duration of injection, good fuel
economy is obtained. The injection duration and the injection timing are controlled by the ECU. Signals
that are input from the throttle position sensor, crankshaft position sensor, intake air pressure sensor,
intake temperature sensor and coolant temperature sensor enable the ECU to determine the injection
duration. The injection timing is determined through the signals from the crankshaft position sensor. As
a result, the volume of fuel that is required by the engine can be supplied at all times in accordance with
the driving conditions.

0 words about lambda, O2 or Oxygen sensor. Even in whole manual.

Skrew - Try posting up on this board;

http://ecuhacking.activeboard.com/

Just Bob wrote:

Skrew - Try posting up on this board;

http://ecuhacking.activeboard.com/

Thanx! I will.
But I found more and more proof of theory that O2 sensor used just for proper CAT working, nothing more. Mainly because Yamaha have GYRT parts for WR250R/X and none of it related to save O2 sensor during full exhaust swap, etc.

skrew wrote:

Just Bob wrote:

Skrew - Try posting up on this board;

http://ecuhacking.activeboard.com/

Thanx! I will.
But I found more and more proof of theory that O2 sensor used just for proper CAT working, nothing more. Mainly because Yamaha have GYRT parts for WR250R/X and none of it related to save O2 sensor during full exhaust swap, etc.

I think you're right. Otherwise the swap to the GYTR pipe would include some reprogramming or an add on EFI module.

Found this at Wikipedia:

Quote :

Air injection

When catalytic converters were first introduced, most vehicles used carburetors that provided a relatively rich air-fuel ratio. Oxygen (O2) levels in the exhaust stream were generally insufficient for the catalytic reaction to occur efficiently, so most installations included secondary air injection which injected air into the exhaust stream to increase the available oxygen and allow the catalyst to function. Some three-way catalytic converter systems have air injection systems with the air injected between the first (NOx reduction) and second (HC and CO oxidation) stages of the converter. As in the two-way converters, this injected air provides oxygen for the oxidation reactions. An upstream air injection point, ahead of the catalytic converter, is also sometimes present to provide oxygen during engine warmup, which causes unburned fuel to ignite in the exhaust tract before reaching the catalytic converter. This reduces the engine runtime needed for the catalytic converter to reach its "light-off" or operating temperature.

Many modern vehicles do not have air injection systems. Instead, they provide a constantly varying air-fuel mixture that quickly and continually cycles between lean and rich exhaust. Oxygen sensors are used to monitor the exhaust oxygen content before and after the catalytic converter and this information is used by the Electronic control unit to adjust the fuel injection so as to prevent the first (NOx reduction) catalyst from becoming oxygen-loaded while ensuring the second (HC and CO oxidization) catalyst is sufficiently oxygen-saturated.

And this is a tricky part: seems that WR250R/X equipped exact for such behavior. Having O2 sensor as part of CLOSED CIRCLE would nullifies AIS at all because ECU was responsible for creating Air/Fuel mixture that suits CAT.

Taken from Wikipedia too:

Quote :

Aspirated air injection

Air injection can also be achieved by taking advantage of the negative pressure pulses in the exhaust system at engine idle. A sensitive reed valve assembly called the aspirator valve is placed in the air injection plumbing, which draws its air directly from the clean side of the air filter. During engine idle, brief but periodic negative pressure pulses in the exhaust system draw air through the aspirator valve and into the exhaust stream at the catalytic converter. This system, marketed as Pulse Air, was used by American Motors, Chrysler, and other manufacturers beginning in the 1970s. The aspirator provided advantages in cost, weight, packaging, and simplicity compared to the pump, but the aspirator functions only at idle and so admits significantly less air within a significantly narrower range of engine speeds compared to a pump. This system is still used on modern motorcycle engines, e.g. the Yamaha AIS (Air Injection System).

Considering quoted above, that CO mode adjustments in DIAG mode we seen at Youtube is demonstration of duplicated functionality built into our WRs for all regions. O2 sensors can be found only in EU models where Yammi need to be 100% sure bike will pass smog tests in all conditions... USA and JP models built w/o O2 sensor as they can be configured from DIAG at regional dealer..

the real question is the bike going to be running to lean with an after market exhaust using the O2 but no AIS ..........like mine is

Seems like it is.
Buy a some Power Programmer and/or visit Lambda-equipped service...

Hi,

my friend & I run an X and a R.
Both with Leo Vince exaust, both with O2 sensors, the X whitout AIS & an "open" Airbox, my R all stock.
No programmers on both bikes.
The only difference is that my R has a little "backfire" explosions & the X whithout AIS is quiet when we close the throttle.
Same performance/topspeed. No problems
The X with 20.000 Km + & the R with 45.000 Km on the clock.

Winter/Snow sucks

Greetz from Germany
Bubbler

Dread Bubbler wrote:

Hi,

my friend & I run an X and a R.
Both with Leo Vince exaust, both with O2 sensors, the X whitout AIS & an "open" Airbox, my R all stock.
No programmers on both bikes.
The only difference is that my R has a little "backfire" explosions & the X whithout AIS is quiet when we close the throttle.
Same performance/topspeed. No problems
The X with 20.000 Km + & the R with 45.000 Km on the clock.

Winter/Snow sucks

Greetz from Germany
Bubbler

thanks

I was starting to think i was the only on out there without a Programmer on a modified bike

Dread Bubbler wrote:

Hi,

Both with Leo Vince exaust, both with O2 sensors, the X whitout AIS & an "open" Airbox, my R all stock.
No programmers on both bikes.
Same performance/topspeed. No problems

Thanx to detonation sensor and good fuel quality both of you still can ride your bikes. In the worst case your engines would be dead.
O2 sensor used only then bike is at idle, and I am pretty sure you balancing between relatively "poor" performance and engine failure. Let one of you try some Wiseco or FMF programmer and then compare performance.

skrew wrote:

Thanx to detonation sensor and good fuel quality both of you still can ride your bikes. In the worst case your engines would be dead.
O2 sensor used only then bike is at idle, and I am pretty sure you balancing between relatively "poor" performance and engine failure. Let one of you try some Wiseco or FMF programmer and then compare performance.

In the german WR/R forum there are basically two groups. One is the "all stock" group, the 2nd did modify a little.
Most of the modified bikes have the Leo X3 mounted because of wheigt reduction & optics.
The Leo is "semi legal" in Germany. FMF & others are not allowed.
I did not like the idea of having a Cat because of overheating on low speeds.

In 5 Years & about 100+ bikes in the forum there is no report of a broken engine.
OK, a price of 1,60 €/liter gas should guaratee good fuel quality.

Performance is just great. We love to chase BMW R1200GS on our small backroads

I will go for a programmer if i have to change to 290ccm because the motor dies... one day in the far future.
I never would install a programmer whitout checking it on a dyno.

Greetz Bubbler

Dread Bubbler have you seen anyone use a staintune exhaust over there

theMISSIONARY wrote:

Dread Bubbler have you seen anyone use a staintune exhaust over there

Nice exahust. Too sad it too expensive.

theMISSIONARY wrote:

Dread Bubbler have you seen anyone use a staintune exhaust over there

Hi theMISSIONARY,

no, never heard about it.
The Leo X3 is the only aftermarket exaust with an E number -> u need that number over here to be legal.
But its still a lot louder than the original exaust. In case of police control with a dB-meter we migth have problems.

The most sexy sounding exaust i ever heard on a 250 was a Doma. Not too loud & super deep sound. But only availabel for the WR/F

Greetz
Bubbler