not running right

[redcap]

Hi All
My BMW F800gs adv has started playing up . It has covered 3000 miles ,all was well until i fitted a powercomander. The pc made a huge difference as they always do. One wet evening it started to run as if it was suffering carb icing (remember that ?) i took it back to BMW Balderston was told they couldn't really do much as the pc was fitted ,however what they did check they said was fine .So most obvious thing to do was remove pc which takes app.3hrs to do .However bike ran fine for a few short trips.Problem solved until Christmas eve ,300 mile run and the bike didnt seem to have as much go as normal .I put this down to the very strong winds ,then at 5000 rpm it would not rev for a few seconds then it would clear a little bit then run again as if it had carb icing ! I am aware that it is fuel injected and doesn't have carbs .Any help or ideas would be appreciated .
Cheers

 

[chipko]

Split airbox hose or similar?

When I last had my F800R ('10, 16,000 miles) serviced the dealer asked me if I'd had any problems with rough running: I'd not noticed any. They said there was a hose out the back of the airbox where a clip had cut through and split it. Apparently it's difficult to see and hadn't showed up before. They were surprised it was running at all. Although out of warranty they replaced it free (took a couple of days for the hose to arrive). Afterwards the bike was transformed - smoother than it had ever been especially at low throttle openings in town. It could have been like that almost from new, but over the three years I had the bike, I put it down to the lightweight crankshaft flywheel (my previous Rockster 80th had one anything but that).

So: may not be the PC, may not show up on electric diagnostics, may be something like a hose, like I had? Hope it helps, and sorry I can't be more specific - the last bike I dared take to bits was my 1976 Honda CB 500/4 which I stripped to the crank after it ingested its own camchain tensioner ... and it started first time after my rebuild!

 

[JJH]

fuel starvation? JJH

 

[redcap]

Hi All
Had the bike checked over at Balderston BMW this morning . Very helpful lads too . I just turned up and they immediately whipped it in the shop to check codes etc . Turns out the lambda sensor was not connected correctly !!! Bike has returned to its lovely self again Horrah !
Cheers

 

[dibbs]

Glad you posted the fix, thanks

 

[Roger Chatterton]

Balderstons are a good bunch. Bought my ex demo F700
from them and they even found me a few "extras" from
their used-bits pile!
Pleased you got sorted- not all BMW Dealers are out to get you!

 

[Nick V]

Hi All
Had the bike checked over at Balderston BMW this morning . Very helpful lads too . I just turned up and they immediately whipped it in the shop to check codes etc . Turns out the lambda sensor was not connected correctly !!! Bike has returned to its lovely self again Horrah !
Cheers

Hi Redcap!

This is a bit of a head-scratch for me. On my '09 R1200GSA, I fitted a Power Commander 5.
Now, on these units, the standard Lambda sensor is disconnected and removed, and a blanking plug fitted to the exhaust - unless the plug-in Autotune module is fitted (in which case, the standard BMW narrow-band Lambda sensor is replaced by a wide-band unit. This sensor interfaces with the PC5 via the Autotune module).

In context of the PC5, the Lambda sensor's function is also slightly different: unlike the standard engine-management setup, it doesn't communicate with the engine ECU or PC5 in real time. Instead, it's used to help the PC5 'adapt' to the fuel map which has been defined by the user. The 'learned' fuelling curve is not accepted by the PC5 until the user gives the go-ahead using the PC5 software.

Was your dealer able to explain how they actually fixed the problem? Because if the PC5 has been fitted according to instructions, it's natural that the Lambda sensor will be giving a fault code - it will be absent from the bike!
There's a good reason for that - if the Lambda sensor remains connected to the BMS-KP ECU, the fuel-enrichment inputs from the PC5 will constantly be overridden by the input from the Lambda sensor (which will be telling the BMS-KP ECU that the outflowing exhaust is too rich).

 

[Nick V]

Redcap, thinking about the symptoms you describe, it sounds as if the bike was running too rich.
Were you using a pre-created fuelling map? If so:

• Did it come from a reputable source?
• Am I correct in thinking you run at sea level?
• What performance mods (if any) do you have on the bike?

Unless you have ready access to a dyno, setting up a PC to give optimum performance is a fairly involved and time-consuming process. You HAVE to know what goal you're aiming for, and how to achieve it.

Also, your dealer didn't have to remove the PC, and they know it. It would have been child's play to simply re-connect all sensor & actuator plugs in the original configuration, and disconnect the 12V+ input to the PC module.
IIRC, there's another way of creating a 'failsafe' that's even easier: PC5s have two terminals, to which can be connected any simple on/off switch. Once that's in place, it's a simple matter to use the PC5 software to configure one of the switch positions as the 'PC map' position, and the other as the 'failsafe' position. (Setting the switch to 'failsafe' overrides input from the PC, allowing the original engine map to be used with no additions from the PC).

If you'd like, get in touch via PM. I think I may be able to source a map you can use as a 'baseline'.

Persist! You will get there.

 

[redcap]

Hi All
I had removed the powercommander completely ! I think I must have not clipped the lambda sensor back in correctly . When I had the powercommander fitted I unplugged the lambda as per the instructions ! The fault with the running when I had the pc fitted was a faulty join on the battery lead . I may repair the lead and refit the pc because it did smooth the running of the engine out a treat ! As standard ( now) she does wheeze a bit from 6000rpm in top but by then you are getting a wriggle on anyway .sorry if I caused any confusion !
Cheers

 

[Nick V]

No worries! Glad to hear it's all coming right.

It's usually the simplest, smallest things that cause the (seemingly) biggest problems.

When you have the PC back on, here's a tip: try aiming for a normal air/fuel ratio (14.7:1) in all the relevant AFR-table cells. That will give a good baseline from which to start. If you get unusual flat spots or 'dead'-feeling areas anywhere in the rev range, increase your enrichment in that area only by 1% each time. If you find the problem getting worse, back off the enrichment.
(I must admit, it's loads easier to get feedback on what you're doing when you have the Autotune plug-in module installed. If you don't have that OR a dyno, you're flying blind.)

BMW have set all their modern bikes to run stupidly lean (anywhere between 15:1 and 16:1), which causes all sorts of flat spots, the well-documented stalling-at-idle issue, and so on.

Also:
- Make 100% sure that you're getting a smooth, progressive increase in throttle-position sensor readout when you twist the throttle from idle to full. If you haven't got the TPS-calibration procedure correct for the Power Commander, you're sunk before you start.
- If you haven't already done so, I'd recommend plumbing in the vehicle-speed and engine-temperature inputs. They're optional, but they will make tuning a lot easier. (The vehicle-speed input is also essential if you want to install the plug-in quickshifter at a later stage.)