erratic idle and lambda sensors

[SpanishJohn]

Hi all,

Ok, so last night after a 20 mile run I'm waiting at the lights and the engine idle was not normal, 1K rpm at best. Still ran ok but every time I stopped...

This morning, out of curiosity I started the bike - all fine (idle back to normal) and then I disconnected the lambda sensors one by one to try and emulate the poor idle of the previous night. Here's the strange bit - it made no difference at all to the (now) smooth tickover??

The bike is a 2005 GS with new coils and well balanced TB's. It did previously have a PCIII connected but I removed that as I was considering a re-map instead.

SJ

 

[Our Gee]

Hello John, for four years of 1200RT ownership I have been plagued with intermittent very rough tickover. Bike has been worked on by two main dealers. Just about everything has been changed under warranty and I changed the Lambada Sensors at my own expense. In the end I have just learned to live with it. Worst idle of any bike I have owned.

 

[Rusty Bolts]

I had similar rough running and changed the throttle position switch thingy, that solved it.

 

[oddshapedballs]

Hi all,

Ok, so last night after a 20 mile run I'm waiting at the lights and the engine idle was not normal, 1K rpm at best. Still ran ok but every time I stopped...

This morning, out of curiosity I started the bike - all fine (idle back to normal) and then I disconnected the lambda sensors one by one to try and emulate the poor idle of the previous night. Here's the strange bit - it made no difference at all to the (now) smooth tickover??

The bike is a 2005 GS with new coils and well balanced TB's. It did previously have a PCIII connected but I removed that as I was considering a re-map instead.

SJ

Put the PCIII back on, remove the lambda sensors and install blanking plugs.

 

[Magwych]

A Lambda giving a "bad" reading will have a far more detrimental impact than no Lambda at all. The ZFE will now that there is no O2 sensor so will just use its "base" mapping. If the O2 sensor gives a false reading, the ZFE will take that reading, then adjust the the steppers and may be other parameters to bring the AFR back into its desire range.

If your bike is idling fine at the time, then disconnecting them is unlikely to have any impact, so no surprises in what you observed.

Is the idle always OK when he engine is cold? The O2 sensors take a while to get up to temperature and are ignored until they do.

If you do remove/replace them, do not touch any part of the sensor that is below the thread, the oils on your skin can have a permanent impact on their efficiency, they are quite delicate considering where they go.

 

[Bendy toy]

Long story but the symptoms sound like faulty coil(s).

Mine with similar problems has just cost me a small fortune.

The idle speed wasnt too bad but could be lumpy at tickover. Stalling was rare enough to believe it was just a "feature".

Recently the fuel consumption increased but its overdue for a proper service. Then fuel consumption went as low as 30mpg and RHS was all sooted up. With coils swapped over left to right the RHS remained sooty. I wasnt able get to BMW so bought a generic lambda - they control the mixture. All seemed ok but then consumption went down again.

This time there was a proper missfire and one coil smelled of burnt insulation (the original RHS coil). This helped but consumption still poor. Swapped lambda sensors left-right (which I should have done sooner). The generic was dirty and rattling so probably always faulty. Running with it disconnected put consumption to low 40mpg. Below normal but not critical.

I ordered a new BMW lambda. Going to collect the weather was warn=m and I had to filter through traffic the engine was stalling at low speed. It normally dips just above tickover then catches back to the correct tickeover speed. It was just dying every time.

I fitted the new Lambda >£150 FFS (the gereric was £50). The bike was still stalling though less badly. Ther service guy did say that when one coil fails the other is often close to follow. I went back and pulled the other coil - sure enough smelly insulation.

So I spent £160 to replace 2 coils (bad enough) plus another £200+ for the lambdas that I probably did not need. In mitigation I have never before had any engine run rich because a coil is failing. That said this is the first twin plug for me.

The problem was most likely the coils all of the time, They seem ok when cold but insulation breaks down when hot. The situation is muddled by the lambda not switching in until engine is hot.

 

[Pukmeister]

Lambada are made by NTK (part of the NGK spark plug group that make automotive sensor components), and can be bought for £70 each. Or you can buy the same part in a BMW carton for twice that price. Those BMW cardboard boxes are expensive!

 

[Bendy toy]

I wish I'd had chance to google that :-(

 

[B4ndit]

A GS 911 would be your friend.

 

[Bendy toy]

A GS 911 would be your friend.

Oh yes!

I've moaned about the cost of the GS-911 but just spent about the same on two O2 sensors; at least one of which I probably did not need.

The OP's original symptoms are like mine (except I also had one cylinder sooted up). I had one coil failing. The other went down soon after. It seems that when one primary coil fails, the other will be along (in my case - very) soon after.

 

[notadrop]

Lambada are made by NTK (part of the NGK spark plug group that make automotive sensor components), and can be bought for £70 each. Or you can buy the same part in a BMW carton for twice that price. Those BMW cardboard boxes are expensive!

Found the details if you want them here:-
http://www.ngk.de/nc/en/product-fin...MW/R%201200%20GS%20ADVENTURE/OZA630-BM1/8882/

and on ebay:-
http://www.ebay.co.uk/itm/LAMBDA-SENSOR-NGK-OZA630-BM1-BMW-MOTORBIKE-/370570070441#ht_1027wt_907

 

[B4ndit]

I believe he has sorted it.

 

[notadrop]

Does any one know what the problem was?
I would be interested as I've been having similar problems (not all the time and not predictable eg sometimes after town traffic, sometimes after motorway use).

 

[B4ndit]

I will text him to come back on line for you.

 

[notadrop]

Thanks B4ndit, appreciated

 

[B4ndit]

Text sent.

 

[SpanishJohn]

Hi all,

Sorry for late response . Yes I resolved it but probably not in a way that will be of any use to most of you who responded to this thread . I put the PCIII back on (loaded with the 'default' map). This in turn allowed me to ditch the lambda sensors. I have the biked booked in for a custom map next monday, but the idle problem has gone and my bike idles smoothly. I suspect, but cannot prove, that one or both of my L sensors was faulty, but after shelling out £170 for new primary coils there is no way I'm paying for new L sensors also.

Thanks for all the responses and good luck

SJ