Bosch 02 sensor for Power Commander

[duke]

I need some giudance here from those in the know:

I bought a PCIII from eBay.
It was listed w/o O2 sensor, and I did not pay enough attention when I bid for the unit.
It is still a bargain though.

Only reason to buy it - to get better throttle response/smoother power curve and avoid lean running.
Not to increase power or similar bulldust.
OK - I admit it - I feel guilty that I left my bike to rot for a while and want to lavish it with some goodies.

Now I have to buy the sensor ... which one though?

If somebody from our spanner gurus MikeCam, CycleRob and the resident sage of UK knowledge Riceburner (to name a few)(anyone not mentioned please do not get offended - PM me for a free hug and inclusion in the list of spanner gurus) can provide helpful insight:

Is this http://cgi.ebay.co.uk/AEM-REPLACEMENT-U ... 3efa597935
the part I need to buy?

I already had a look on the Dynojet website ... and they look more or less the same.
But I would prefer not to assume.

Cheers

Duke

[boxermania]

Based on your post ,I assume you bought a PC for use in applicatons that don't require a O2 sensor. Likewise, I gather that you live in the UK.

That being said:

Does your bike have an O2 sensor? It can be found on the front of the Cat converter. If so, you can still use the PC you bought as long as you understand the following.

The PC and all fuel nanny's, basically take the trigger signal from the ECU and re-process it to add or substract a minute amount of time to the original signal, this in turn will allow the injector to remain open a bit longer in one case or shut off earlier on the other. The result being a richer or leaner mixture in each case.

The O2 sensor in our bikes is the narrow band type (common and less sophisticated than the WD, wide band) and only comes to play when the engine is running steady state, like cruising on the highway at a preset speed.

Once the load of the engine changes, via additional opening of the throttle, the O2 sensor is out of the picture and a preset A/F map comes to play. (there are several maps stored in the ECU and the selection depends on the country the bike is beng sold)

So in closing, the PC you have will give you what you are looking for, the only difference will ctake place when you are running steady state and this is what will happen:

Since the PC will be trying to enrich the mixture slightly, making it richer, the O2 sensor will in turn signal the ECU to cut back on the time pulse to the injector, in essence, not affecting the steady state operation of the O2 sensor. (Read, increased economy)

The PC you have should have a power lead, a ground lead and two plugs to connect to the injector plug comming from the ECU and the other to connect to the injector. You already own it, no harm in trying it.

Good luck and keep us posted.

[duke]

First of all - thanks for taking the time to reply.

The assumption that I live in the UK is correct - the bike has to be Euro-specification Rockster.
I honestly do not know if the bike has O2 sensor and I have not been to the garage since (work is taking over my life).

Generally speaking I knew roughly what the PC does to the signal coming from the ECU, but did not know the old sensor is narrowband (trigger-switch type operation, as opposed to scaling).
Makes quite a lot of sense in regards to the feedback from the O2 sensor back to the ECU asking to lower fuel squirt amount in response to the PC adding more.

Speaking of leads ... it has the following: 2 x 2 injector couplers, 2 x TPS couplers, O2 sensor coupler (square), ground lead, some round (single wire) connector looking similar to the plug from the old O2 sensor and a 4-pin white plug (just read it is for optional gauge).
So my assumption is that it takes power from the old round O2 sensor coupler?
Or am I way off the mark?

A few questions:

Is it possible to fail MOT (annual test to prove vehicle suitable for public roads) as the PC will add more fuel ... and if there is no O2 sensor to counter it? I think they measure exhaust output under different throttle levels.
Is it not beneficial to add the O2 sensor (as opposed to harmful by not adding it)? Is it it beneficial to the tune of spending $90 to obtain it? (I paid circa $120 for the PC)
General point while buying the PC (apart from stated before) was also the option of adding aftermarket can (I have already have K&N filter) w/o messing-up the A/F ratio and running too lean/rich.

Thanks

Kind regards

Duke (awaiting Saturday to get the bike MOT-ed and road legal again)

P.S. The hug is in the post

[duke]

Quick update - the bike has O2 sensor, and will be a massive pain to get to it.
In very un-German fashion the bike designers have lobbed it just between the engine block on the front top of the Cat.

Bugger

[boxermania]

Sorry for my late reply as I have been on vacation since Dec 9th.

The bike should not fail the MOT after proper installation of the PC. Generally speaking the maps available for the PC are tailored around the known shortcomings, such as surging at light load operation and roll on acceleration.

The addition of a can will certainly improve the power, slightly and the acceleration. Check the PC site for the different maps available for download, you can also, with a laptop make chnages n the A/F map, however that is better left for those in the know and with the availability of a wideband O2 sensor to monitor the A/F ratios.

[DrAlf]

Unscrewing the OEM sensor and installing the aftermarket sensor is no big deal. However in order to get the most from your PCIII you’ll want to get it setup properly. I’m in Banbury, UK and my local engine tuner will install and setup the power commander very cheaply. He’ll also be able to source the right O2 sensor if required. Let me know if you’re interested and I’ll put you in touch. The PCIII certainly improves throttle response – it’s like a different bike:)