Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet with the UCE engine => Topic started by: chinoy on January 29, 2010, 06:39:30 am

Title: re-visting the missing O2 sensor.
Post by: chinoy on January 29, 2010, 06:39:30 am
Ok so thanks to Singh Ji and all the helpfull souls here. This is what we have figured out so far.

There are two pins on the ECU that talk to the O2 sensor
Pin 7 marked HEGO
Pin 17 marked HEGOHT

They dont tell us what HEGO is or what HEGOHT is by common sence would tell us that pin 7 is your 0-1 Volt O2 reading and Pin 17 is your heater power.

If somebody could confirm this with a simple multimeter.
You put one probe on the frame and the other into pin 17 with the bike runing you should see 12-13 volts d/c
If you where to do the same check on Pin 7 you should see 0-1 Volt.

On our bikes Pins 7 and 17 are blank.
First test I did was check for voltage on both pin 7 and 17 I got none..
Which tells me that even if I where to hook up a 4 wire heated NB sensor it would not work.
The next step would be to introduce a 0-1 volt signal on pin 7 and see if the AFR changes. But seeing as there is no +12 volts on the heater circuit it is safe to assume they have  not loaded the same firmware as you guys get.
So even adding an O2 sensor will not serve any purpose.

If AFRs start to change with the 0-1 volt inputs then we could just add a single wire O2 and feed the single wire to Pin 7.

You guys are lucky your engines auto tune to elevation and changes in the ex.
Hope somebody is able to check these pins with a multi meter.
Title: Re: re-visting the missing O2 sensor.
Post by: ScooterBob on January 29, 2010, 03:38:36 pm
Chinoy - You are right here - Just out of curiosity - what part number do you have on your processor? Also - there should be a coloured dot on the label .... what colour is it?I suspect that the base wiring for the O2 sensor may be in your harness, so all you'd have to do is add the right ECU and an O2 sensor - but I'm not sure. I have an inquiry or two out to the Factory about this sort of thing - but as you may imagine - it isn't a huge priority, my curiosity. You may have a better go of finding out the vital info directly from an Indian dealer who asks of the Factory ..... BTW - The O2 sensor generates "about" 400mv on average (higher or lower for the mixture ....) on average - and I think that's the default in the processor if it gets no input from the O2 ..... 
Title: Re: re-visting the missing O2 sensor.
Post by: chinoy on January 30, 2010, 10:04:45 pm
Im in direct contact with a prety senior RE guy.
Every question I ask is answered by a I dont know.

When I ask ok who will know. Im told only the R&D boys will know.

We have a diffirent wiring harness here.

You are right in most ECUs .4 volts is what you expect to see. If for any reason the ECU detects a problem with the O2 sensor. or the IAT sensor. It subs in a default value.
And to be on the safe side this default value is normally on the richer side.

Its an old trick to cut the O2 sensor to your ECU in the formula races which use the swift engine.

But in our case I dont think the firmware loaded even activates that pin.
Knowing if you get 12 Volts on Pin 17 when your power on the Bike would be a big help.

Im working on figuring out a way to just richen up my mixture a wee bit.
To take care of the new up-swept exhaust. And improved air flow thru the engine.
With the performance Fileter and new ex.

Im confident I can pull it off.
Lifting the rev limiter is proving a harder task though.