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Discussion Starter #1
I'll start at the beginning...

2016 Icon with Termi race slip-on with Up Map key installed, no baffles.. engine light had never been on in 1500 miles.

I didn't like the surging at low rpm/speed so I installed a pair of o2 sensor eliminators (eBay ones from Greece), physically removed the o2 sensors and used plugs to cap the holes in the exhaust pipes.
Took it for a ride, surging had gone BUT when accelerating hard ie. throttle opened up lots, if I then fully closed the throttle for 2 or 3 seconds, the engine management light would come on.
It would stay on for around 2 seconds.
I presumed that even though the o2 sensor eliminators gave a constant voltage value for the ecu, the ecu wasn't entirely happy and so produced the engine management light. At this point I must point out I still had the oem air filter in.

I felt that I wanted the fuelling to be spot on so I had my ecu flashed by Rexxer.
I told them I had the Termi race slip-on, up map key installed, no baffles, o2 sensors disconnected and physically removed and that I wanted the o2 sensors switched off in the ecu. I also installed an pipercross air filter.

Put the newly flashed ecu back into the bike, started it up, let it idle for 5 min (didn't touch the throttle) and then rode it gently for 10 miles after which I rode it harder for another 10 miles.
When giving lots of throttle and then closing the throttle fully shut (same way as before), yet again the engine management light comes on in the exact same way as before!

I know I need to get it on a diagnostic machine to see what is going on and for it to hopefully tell me an error code.
It's been suggested that a sensor is playing up and originally with the o2 sensors connected and in use, it was masking the fault.

Has anyone experienced anything similar or have any ideas?

Many thanks.
 

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I'll start at the beginning...

2016 Icon with Termi race slip-on with Up Map key installed, no baffles.. engine light had never been on in 1500 miles.

I didn't like the surging at low rpm/speed so I installed a pair of o2 sensor eliminators (eBay ones from Greece), physically removed the o2 sensors and used plugs to cap the holes in the exhaust pipes.
Took it for a ride, surging had gone BUT when accelerating hard ie. throttle opened up lots, if I then fully closed the throttle for 2 or 3 seconds, the engine management light would come on.
It would stay on for around 2 seconds.
I presumed that even though the o2 sensor eliminators gave a constant voltage value for the ecu, the ecu wasn't entirely happy and so produced the engine management light. At this point I must point out I still had the oem air filter in.

I felt that I wanted the fuelling to be spot on so I had my ecu flashed by Rexxer.
I told them I had the Termi race slip-on, up map key installed, no baffles, o2 sensors disconnected and physically removed and that I wanted the o2 sensors switched off in the ecu. I also installed an pipercross air filter.

Put the newly flashed ecu back into the bike, started it up, let it idle for 5 min (didn't touch the throttle) and then rode it gently for 10 miles after which I rode it harder for another 10 miles.
When giving lots of throttle and then closing the throttle fully shut (same way as before), yet again the engine management light comes on in the exact same way as before!

I know I need to get it on a diagnostic machine to see what is going on and for it to hopefully tell me an error code.
It's been suggested that a sensor is playing up and originally with the o2 sensors connected and in use, it was masking the fault.

Has anyone experienced anything similar or have any ideas?

Many thanks.
I'll say you're on the correct track thinking it's a Lambda sensor problem.
I've seen exactly the same thing with the bypass diodes. I did a diagnostic test and it came up with 02 sensor open circuit.
As you say, it's only on the over-run from higher up the rev range and the lamp comes on at 2k revs.
To be honest I've not spent much time trying to check it out but would like a fix if possible.
 

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Discussion Starter #3
I'll say you're on the correct track thinking it's a Lambda sensor problem.
I've seen exactly the same thing with the bypass diodes. I did a diagnostic test and it came up with 02 sensor open circuit.
As you say, it's only on the over-run from higher up the rev range and the lamp comes on at 2k revs.
To be honest I've not spent much time trying to check it out but would like a fix if possible.

Thing is, I've now a rexxer flashed ecu with o2 sensors turned off in the ecu. I've also taken out the resistors and keep the o2 sensors off the bike as in theory the ecu doesn't look for or try to use them anymore.

Maybe for reason the o2 sensors haven't been disabled correctly by rexxer though I can't see that being the case.

Thanks
 

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Thing is, I've now a rexxer flashed ecu with o2 sensors turned off in the ecu. I've also taken out the resistors and keep the o2 sensors off the bike as in theory the ecu doesn't look for or try to use them anymore.

Maybe for reason the o2 sensors haven't been disabled correctly by rexxer though I can't see that being the case.

Thanks
My theory there would be if you have no lambda sensors and no bypass resistors plus Rexxer didn't delete the 02 sensors properly then the lamp would light up right away
 

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Discussion Starter #5
My theory there would be if you have no lambda sensors and no bypass resistors plus Rexxer didn't delete the 02 sensors properly then the lamp would light up right away

I have been thinking... rexxer create the fuelling map from 0% throttle to 100% throttle so let's say the o2 sensors hadn't been disabled, how would that work?
 

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I have been thinking... rexxer create the fuelling map from 0% throttle to 100% throttle so let's say the o2 sensors hadn't been disabled, how would that work?
If the 02 sensors and the bypass diodes have been removed as you say, then the warning lamp would be lit all the time not just on the over-run due to open circuit if Rexxer had not disabled them.
If they are disabled and you are still showing faulty sensors then there must be another sensor linked in that requires a signal from the 02 circuit.
 

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Discussion Starter #7
Many other people on here have had a rexxer ecu remap with o2 sensors disabled at the ecu and also physically removed without any engine lights.

I have a feeling another sensor isn't working correctly.
 

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Many other people on here have had a rexxer ecu remap with o2 sensors disabled at the ecu and also physically removed without any engine lights.

I have a feeling another sensor isn't working correctly.
The bike I have here doesn't have a Rexxer fitted so that ruled out your suggestion that they didn't delete the 02 sensors properly, for me anyway. Plus your lamp isn't lit all the time.
I was thinking the bypass diodes were incorrect or faulty (I've tried two sets) but you've kind of proved it's not that as you don't have them fitted now, which also proves your Rexxer's good.
My diagnostic test showed an open circuit, this seems spurious too as even with the Lambdas plugged back in the fault was still there.
 

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Discussion Starter #9
I decided to install the o2 sensors back onto my bike and connect them back up.
Took it for a test ride and the engine light stayed OFF!

I pulled over, quickly disconnected the o2 sensors and did the same route, the engine light came ON.

What I can't work out is why the o2 sensors are affecting the fuelling of the bike if they are turned off?

So here are my theories are:

1) RexXer haven't properly turned the o2 sensors off in the ecu.

2) RexXer have disabled the o2 sensor in the ecu but for some reason the ecu is still receiving a signal from the o2 sensors.

Anyone got any ideas??
Thanks
 

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The Rexxer may disregard the output from the Lambda sensors but the ECU still expects to see them, that is the case with Termi up-map. Strange though that the engine light should only come on with a closed throttle.
 
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Discussion Starter #11
The Rexxer may disregard the output from the Lambda sensors but the ECU still expects to see them, that is the case with Termi up-map. Strange though that the engine light should only come on with a closed throttle.

Hi Derek,

I thought the RexXer flash had the ability to turn off the o2 sensors completely but this is not the case.
The RexXer flashed ecu keeps the o2 sensors active but doesn't use the data as there is now a fuel map in those sections of fuelling that the o2 sensors would previously be used for. So it's more of a case of ignoring rather than a disabling.

I had the bike on a diagnostic machine this evening...

The picture is the error codes when it was first checked... not sure what the first code Is?

The faults were cleared, I rode it round the block and error codes were looked at again.

This time just two error codes for the o2 sensors.... 0133 and 0153.

There were no other fault codes. I'm only guessing but it seems that at closed throttle the ecu is using the data/signal from the o2 sensors even though it's not meant to be obviously.
 

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Discussion Starter #13
Have a read above Hui... the RexXer turns off the warning light for the o2 sensors but keeps them active still ( I thought the RexXer flash actually turned them off).. the flashed ecu uses 100% fuel map so has no use for the o2 sensor data/signals.
 

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Have a read above Hui... the RexXer turns off the warning light for the o2 sensors but keeps them active still ( I thought the RexXer flash actually turned them off).. the flashed ecu uses 100% fuel map so has no use for the o2 sensor data/signals.
Read what ?
You say 'many' people have the Rexxer with the lambda's removed without any problems.

"Many other people on here have had a rexxer ecu remap with o2 sensors disabled at the ecu and also physically removed without any engine lights."
 

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Discussion Starter #15
Read what ?
You say 'many' people have the Rexxer with the lambda's removed without any problems.

"Many other people on here have had a rexxer ecu remap with o2 sensors disabled at the ecu and also physically removed without any engine lights."


Sorry I obviously didn't understand what you meant by 'How's that then?'
 

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I'm not disagreeing, just wondering how it can be, or more so why I have the lamp coming on. It doesn't affect anything or cause probems but if there's a fix then I'll do it.
 

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I really don't know tbh.

If I find out a solution I will let you know.
One thing I do know is that it only happens after the engine is thoroughly heated up and below approx 2k
This makes a bit of sense as the Lambdas are not active during cold running or above 2k revs.
Maybe tricking the temp sender could be a fix, even just as a trial.
 

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Discussion Starter #19
For anyone that is interested.. the problem I had has been resolved!

I had to buy an RexXer evo user device in the end to be able to load fuel maps on myself.
Loaded a new fuel map from RexXer and the light doesn't come on now.
It turns out I had a problem with the first fuel map that RexXer flashed. They don't know as to why the map didn't work properly.
 

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Thanks for the update. I don't think I'd have been that willing to spend so much cash on it but I'm happy to hear that you've got it sorted.
 
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