Excessive fuel consumption, recently fitted AF-XiED

[Marke123]

Hi Guys,
I would like to see if there any suggestions to try and resolve an issue with really poor fuel economy that has suddenly occurred.
I'm getting 140- 150 km before the green lights comes on compared to about 200 km normally.
The best would be 220 km for gentle touring and maybe 180 km for commuting.

History:
Balanced 1200 injectors at 23,488 kms.
AF-XiED fitted at 24,000 kms. I couldn't get the plug in R1100S with connectors as it's not longer supplied.
Instead it's the Universal unit where you cut into the wiring loom.
I initially I set the AF-XiED to position 7 (recommended).
I had some issues with the bike not free returning to idle at about 2K and posted a thread at he time.
At this stage no issue with consumption, just the hesitation returning to idle.
All was good.
A Staintune exhaust was fitted at 26,320 kms
I'm on 29,000 km now.

3 tanks ago I changed the setting to position 5 as I was getting poor economy (150 km until green light comes on).

This should make the bike leaner. The lights flash 5 times on start sequence to show setting.

I'm not saying the AF-XiED is the issue.

Things I need to check:
- valve clearance (was done 17,560)
-TB balance (was done 23,400)
-check all plugs are firing (iridium plugs fitted 13,777).

I will get to this soon but the bikes starts and runs well. Doesn't have extra vibes.

I wonder if I haven't install the AF-XiED correctly or can the O2 sensor fail or maybe the connection from the mototronic to the AF-XiED has broken?
It's seemed to have worked for 3,000km.
The unit gives all the correct lights for starting up and acknowledging the setting.
If I blip the accelerator an orange light comes on and off so it seems to respond to different O2 levels.
It appears I have cut into the power correctly (unit powers up) and cut into the O2 sensor as the lights change when revved.
As mentioned, it has been good for a while.
But I wonder if the sensor is good or if there's air leaks in the exhaust from the Staintune?
No leaks where the headers join the Staintune with gaskets.
There is some leakage at the pipes go vertical but it's after the sensor.
Where do I start?
It appears to have occurred 3,000 since fitting exhaust and AF-XiED so probably not related.
How can you tell if the O2 sensor fails?
I don't believe there's an engine warning (FI) light on these bikes so how do you know if there's an issue?
How can you test a O2 sensor?

Any thoughts?


Regards Mark.

[wswartzwel]

Have you tried disconnecting the AF-Xied and seeing how far it goes on a tank? That would tell you if it is the issue.

The purpose of those add ons is to add more fuel, so you can expect less mileage when installing one.

[boxerebel]

Make sure the unit is located away from the alternator. When I installed mine I parked it between the ECU and the alternator and the bike ran funky. I now have it located at the rear of the tank under the seat , probably where you have yours, but you never know.
Some kind of shielding might be good as it didn't seem to like electrical interference.

[BigDav]

Like you, when I installed the AF-XiED, the fuel economy went into the ****ter. Back to stock it went.

[boxerebel]

I have the setting on 7 and get 230km+- on the highway before the warning light.

Initially the mileage was crappy , but over time it recovered. Maybe Motronics needs awhile to learn the program.

If there is no signal from the O2 sensor then the system would be in open loop, and in an enriched state.

Someone more versed in this might explain, open/closed loop, narrow/wide band sensors etc. There is scads of info on the BMWOA site regarding this topic.

Beemerboneyard (supplier) says unit needs strong signal from O2 sensor to perform.
Euro MotoElectrics sells one $59.

Check out BMWOA org. thread on the unit. All positive reviews. roger 04 rt on the forum developed this thing. Maybe you're wiring isn't correct, If you contact him maybe he can advise.

Afx- id and lennies sprockets are the best engine mods I've done to this bike. Better mileage, throttle response , and low rpm manners.

[Roger 04 RT]

I’ll try to get back to you tomorrow.

[Marke123]

Hi Roger,

Good to hear from you.

So far I have tested the bike to see if the spark plugs and ignition coils, leads etc are working.

The test was to remove the stick coils on the primary and insert old plugs. They were earthed to the bike.
I started the bike and it ran without issue on secondary plugs alone. There was good blue sparks on the primary spark plugs.
I then reconnected the primary stick coils to the plugs and disconnected the secondary plugs, connected the leads to the old spark plugs and started the bike.

Again the bike ran well.
Revved freely to 5k or so.

Therefore I conclude the coils, leads, plugs, hall sensor are all good.

Still need to check:
-TB balance (but the bike feel fine)
-The wiring is correct from the AF-XiED to computer.

Happy to carry out any checks etc.

How do I check the O2 sensor?

Could be any thing else as well.

As suggested by wswartzwel, I can disconnect AF-XiED and test in standard format.

It seems others have also experienced increased fuel usage.

Regards Mark.

[Marke123]

Here's the update.
I've pulled off the tupperware off, removed the tank and examined the splice where the AF-XiED is connected to the O2 sensor.
Looks like I've spliced into the earth and not the signal from from O2 sensor!!!
Just trying to purchase some POSI LOCK connectors to correct my error. You can't solder these wires.
I'll leave the battery disconnected to reset the computer so it can re- learn a map when I start the bike again.
I'll also report back of the outcome.
It's nice to find an issue at least.
Have to sack the guy who installed it!
Regards Mark.

[Roger 04 RT]

Mark,
You should have a wiring diagram with the AF-XIED kit. Also, you should be spicing into the O2 sensor cable, not the bikes harness.

Here are the steps:

Connect the red AF-XIED wire to the white o2 wire going to pin 1

Cut the Black O2 3” from the connector. Connect the white/blue AF-XIED wire to the cut black wire going to the p2 sensor. Connect he blue AF-XIED wire to the black wire going to the o2 connector.

Cut the Gray O2 wire. Connect the white/yellow AF-XIED wire to the cut gray wire going to the O2 sensor.

Which step did you get wrong?

[Marke123]

Hi Roger,
I don't recall any instructions with the kit. But I will re read the paperwork.
The is a wiring color description, but not instructions on how the wire the universal kit.
I did wire into the O2 sensor.
I spliced into the grey (earth) and not black.
I looked at the wiring diagram for the bike and tried from there.
Hopefully I'll see an improvement now!
I had another thread where the throttle was hesitating at about 2k when I rolled off the throttle.
I'm sure that will rectify itself power now.
I'll let you know if a few tanks for fuel's time.
Regards Mark.

[Roger 04 RT]

Hi Mark,

Using the gray instead of black will cause problems.

Gray, though, is not earth, it’s the O2- lead and is biased to +140mV. That’s why it needs to be cut, and you must connect the white/yellow wire to the O2 sensor side of the cut. The connector side of that cut must be insulated and left unconnected.

Did your instructions and harness come with a white/yellow wire in it? If not you have to add a wire. I can explain that, let me know. THE AF-XIED WORKS MUCH MUCH BETTER WITH THE GRAY WIRE CONNECTED CORRECTLY.

Also read here: https://advrider.com/f/threads/2004-r1150rt-wideband-o2-sensor-project-and-af-xied-for-bmw.749080/page-110#post-38438354

[Marke123]

Thanks Roger,
I definitely did not get these instructions with kit, nor did did I get any instructions like what you posted 10/11
It would be much better to get the 'plug and play' version.
I can see both grey and black need to be cut from the drawing from you link.
I've only just put the bike back together, grrr.
I'll wait until some new POSI LOCKs arrive and have another go.
Just checking those instruction are for 1150. Please confirm they are for R1100S also.
Maybe the heading should be changed to include R1100S (if this is true)?
Thanks for your assistance.
I'll report back soon.
Regards Mark.

[boxerebel]

Maybe you're wiring is incorrect! Seriously, with no instructions, what did you think the chances were this would work out!

[Roger 04 RT]

Originally Posted by Marke123

Thanks Roger,
I definitely did not get these instructions with kit, nor did did I get any instructions like what you posted 10/11
It would be much better to get the 'plug and play' version.
I can see both grey and black need to be cut from the drawing from you link.
I've only just put the bike back together, grrr.
I'll wait until some new POSI LOCKs arrive and have another go.
Just checking those instruction are for 1150. Please confirm they are for R1100S also.
Maybe the heading should be changed to include R1100S (if this is true)?
Thanks for your assistance.
I'll report back soon.
Regards Mark.

Because I came up with this idea, I try to help where I can. Yes, the 1100s and 1150 use the Motronic MA 1.4 so the instructions are the same. Who did you buy your kit from? Beemerboneyard is currently the only sales outlet and they include the instructions. Contact Mike if you didn’t get them.

I agree about plug n play. Pass the feedback to mike at BB and Steve at Nightrider. Apparently they’ve gotten hard to come by.

[Alfa145V6]

The plug and play is so easy to do. I think I read that the actual plugs are now a crazy price, hence the unit isn’t supplied with them.
The unit made a nice improvement to my bike. The engine seemed ‘creamier’ and pleasanter to use. Probably not the best description but there you go!

[Marke123]

I'm really pleased to report the bike runs much stronger.
If you blip the throttle there's a sharp response.
Starts a little better, idles a little better.
The exhaust has a bark to it now.
I've been commuting so I won't get the best economy.
I've only done 150kms on this tank but the light isn't on, so looking promising.
I still need to ground the O2 sensor as outlined by Roger.
That should occur this weekend and I can report back on that. I expect a few tanks of fuel will need to go through the bike for the maps to settle down.
Thanks for all the assistance and regards Mark.

[Marke123]

Hi Guys,

Glad to report next tank got 205 km's before the light came on on a long easy tour. On the same trip I had previously achieve 220 km's until the light came on.
So it's moving in the right direction. I haven't started to adjust the pot on the controller yet.

Roger 04 RT,

I will ground the O2 sensor as requested when I next have the fairing off the bike.
I'm not sure of the intricacies of the controller but was wondering when the O2 sensor is grounded (not 140mV), is that the same effect of (as an example) selecting 7 instead of 8 on the controller?
I had seen same graphs showing how the narrow band sensor had 0.5 V at the correct AF mix and assume this controller just offsets the voltage by an amount.

Regards Mark.

[Roger 04 RT]

Originally Posted by Marke123

Hi Guys,

Glad to report next tank got 205 km's before the light came on on a long easy tour. On the same trip I had previously achieve 220 km's until the light came on.
So it's moving in the right direction. I haven't started to adjust the pot on the controller yet.

Roger 04 RT,

I will ground the O2 sensor as requested when I next have the fairing off the bike.
I'm not sure of the intricacies of the controller but was wondering when the O2 sensor is grounded (not 140mV), is that the same effect of (as an example) selecting 7 instead of 8 on the controller?
I had seen same graphs showing how the narrow band sensor had 0.5 V at the correct AF mix and assume this controller just offsets the voltage by an amount.

Regards Mark.

Hi Mark,
That’s an astute question. First, the AF-XIED has do to more than a simple offset so it has has a microcontroller and does some processing. However, your question is a good one.

Because of the shape of a narrowband O2 sensor’s oxygen/voltage transfer curve, with the AF-XIED grounded and the O2 sensor “grounded” to 140 mV, setting 7 becomes about setting 3-4. That actually results in a fueling improvement, just not as much as you were expecting.

Again because of the transfer curve, you can go to the max setting (11 IIRC) until you add the ground wire and that will get you to about 5-6. If it was me, I’d go to max now and dial back to 6-7 when you add the ground.

Remember though that you need to cut the gray wire and then ground the O2 side of the cut, and leave the ECU side of the cut floating.

[Marke123]

Thanks Roger,
Understand to cut grey wire etc.
I will report back when I have further news.
Regards Mark.

[Alfa145V6]

Oh my word, this seems super technical. I’m so thankful mine came with the plugs.
I enjoy my simple life 8-)