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[ric]

I'm aware it's located between fully closed and fully open throttle positions but does anyone have a definitive answer as to where it lies in relation to throttle butterfly position or speed in top gear?

[papasmurf]

What bike and more of an explanation please, (it is a complex and very technical subject.)

[ric]

Enfield Bullet EuroIII version.
I'm thinking of trying out an electronic box of tricks which lowers the output voltage from the Lambda sensor (which is not a simple in-line restistor) so the fuel injector pulse is constantly modified by the ECU to supply an AFR of 13.4:1 but (unfortunately) it only affects closed loop fuelling. Just needed to know if it's worth the trouble. I've just replaced a 330 Ohm resistor with a working Lambda - the resistor was as a temporary fix so I now have the option to try something different.

[ric]

It's a voltage divider (apparently) which is not a fixed resistor but a device to constantly change and modify the output signal between the sensor and the ECU - thought it might be a cheaper option to improve (some of) the fuelling.

[ric]

I was a bit loath to remove the seat/rack/tank just to plug it in to see if it actually did anything without other import other than being told 'it will work' and it certainly did! Fortunately I managed to fish the connector blocks out from under the tank so simply plugged it in and went for a ride.
Sadly I didn't appreciate the extra thump through the foot rests nor the very noticeable on/off transition between idle/not idle - and it looks rubbish on the bike

[Rattlebattle]

Never come across one of those before - snake oil perhaps, like a Boosterplug? (Though the Boosterplug does work after a fashion). AFAIK open loop is idle and off-idle; it is the transition from open to closed that causes a hesitation on many EFI bikes. It's a pity one can't just remap the ECU using a laptop (or Android device) like I can with my Triumph (and have done with excellent results). I can't see how one can change the AFR using a device to interfere with the signal from the O2 sensor. That would be too easy and would cost Dynojet a lot of sales. Most aftermarket tuning devices require removal of the O2 sensor; not sure that trying to do something with the narrow band sensor fitted is likely to work, but good luck anyway.

[ric]

Definitely not snake oil - there's around £70 worth of electronics inside that box to provide a square wave pattern output signal to the ECU so the fuelling ends up being corrected in closed loop to run at 13.4:1 instead of 14.7:1


I went over to the new premises of the guy with the dyno this morning only to find he no longer has one! so I'm currently unable to show the before and after AFR ratio's with/without this device fitted.

Anyway having unplugged it and feeling slightly depreciative of the stock performance I've plugged it back in and increased the idle a little to remove some of the transition snatch between idle/off idle. Guess I'll just have to get used to the new feel of the engine along with the deeper exhaust note it now has.

[ric]

BTW I've a performance map for the mechanical speedo 2010 bonny which I cobbled together a few years back which you're welcome to try if you need something to do needs Tors, hiflo filter and no lambdas.

[Haggis]

Quote "AFAIK open loop is idle and off-idle; it is the transition from open to closed that causes a hesitation on many EFI bikes".

This is back to front, closed loop is idle and cruise or steady state running where the ECU uses the lambda signal to control the mixture to try and achieve 14.7:1. Anything else like accelerating up through the gears or when the throttle is actively moving the ECU does not use the lambda signal so reverts to ECU basemap.

[Rattlebattle]

Ric: Thanks but I have a TTP map on my Thruxton, which is one of the last air/oil cooled ones (2016) with the CANbus clocks. It has TORs, hi -flow air filter, breathe inlet to replace standard snorkel, airbox baffle removal (worth 2bhp alone apparently). O2 sensors and SAI both removed and disabled in TuneEcu. All this equates to a 16% increase in torque and a total transformation of the bike. What is this electronic kit you've fitted to your RE?

Haggis: Yep; I got it the wrong way round.