Intermittent Stalling + Idle Hunting Problem

[snaponphil]

Hello, I have no idea how to do that, never attempted reading from power commander before.

The latest for me is that I visited Blakemore Racing in Bristol who supplied and setup the power commander. Disappointingly he tested nothing accept to rev the bike hard which caused a backfire nearly every time on deaccelerate. He said this is not normal and did not believe it was the power commanders fault. He disconnected the power commander and it was still backfiring once one deaccelerate. I rode back to Plymouth. Going up the bike cut out only once in traffic. Coming back the bike cut out once slowing down to stop at a service station.

I haven't been out since. I need to ride and get the bike to fault before I move on further. BMW chap told me to remove a cap on left and right cylinder which is held by two screws, and see if there is any carbon build up as this has been known to cause a problem before. I haven't done that yet because I want to get the bike to fault at every stage.

Upon speaking with BMW further, its my suspicion that at least one coil is failing based on my symptons, what BMW have told me are the possibilities and what has been posted on my thread. But it's only a suspicion, nothing solid yet.

Either way, I don't really want to have to strip my bike back to stock for BMW to test cause I know its not the exhaust or the air filter causing that.

Hi, which part of the uk are you close to.?
I have a gs911 code reader which would be the first step really... Although disconnected oxy sensors are not a good idea as system never gets into closed loop fuelling control which is important (more so) at lower or idle engine speeds.
May I also suggest you find a good independent (preferably BMW enthusiast) as have worked with both main dealers & Indys in the past, & found not ALL main dealers have a good diagnostic guy available.
I don't know Steptoe but his posts seem intelligent & distance may be a problem, but poss worth it as a good guy will save you ££ in diagnostic time.
& yes ignition coils won't generally show up As a logged fault on these bikes, so process of elimination as per previous posts..

Good luck.. (& a steep learning curve ahead I'm sure)

 

[SteveM]

Hi gsbiker, I don't know where you are situated in the UK, I'm in East Cornwall. If you're nearby I've got a GS911 and would gladly look for any error codes for you too.
Regards, Steve.

 

[Wreford Miles]

My HP2 did something similar, it was a lose TPS connector.

 

[gsbiker]

Hello, I'm very grateful to the kind offers of advise and help. I live in Plymouth.

 

[gsbiker]

Hi gsbiker, I don't know where you are situated in the UK, I'm in East Cornwall. If you're nearby I've got a GS911 and would gladly look for any error codes for you too.
Regards, Steve.

Hi steve, that sounds promising. However if the coils are faulty the GS911 would not pick anything up am I right?

Also, My Power commander has now been disconnected but I still have fitted my headers with no cat, ackrapovic and performance air filter? Would that no upset any codes or create new ones which mask any genuine fault? I know BMW won't look at the bike until I put the bike back to stock!

Paul

 

[Mistacat]

Sounds like lower coils at fault, see if you can find someone local with a GS1200 to swap them over and see if that sorts it.
GS911 will not show up a code for coil misfire.
The mods you have listed will not show any error codes on GS911.
You are right to run the power commander with the 02 / Lambda sensors removed. This will show 2 fault codes for each cylinder on the GS911 Heater circuit & lambda output. ( this is not a problem).
If you have a GS911 available check output of temp sensors ( if reading a long way out could put it in cold start settings)
Alternatively If you can borrow an air fuel ratio meter this would also tell you the same.
No good looking at the lambda output on the GS911 as it will be too far out for the narrow band lambda sensors to deal with.
Just my thoughts.

 

[SteveM]

Hi Paul, unfortunately I'm no expert when it comes to the GS911 and its operational capabilities, though I expect you'll find plenty of well informed people on here who are and know it well. I've owned my GS911 for years as well a couple of 1200GS's and luckily have never had bike problems that require the 911's diagnostic abilities to be used much. However, my offer still stands. If you think you would benefit from hooking into my GS911 you're more than welcome anytime, I'm about 12 miles from the Tamar bridge.
Regards, Steve.

 

[Mistacat]

I would take up SteveM`s kind offer.
GS911 / Engine / Realtime values.
Note the injector pulse width at idle when it is running ok & compare it with when it is running rough at same rpm & TP.( should give an idea if it is a fuel or ignition problem)
Check the TPS is 0 at idle, have been known to flash between 0 - 100 ( could be connector).
Use the GS911 log facility when ok and running rough and post the logs on Hexcodes forum,( some clever people on there)
Just another couple of thoughts , Good luck.

 

[Bendy toy]

North Oxford BMW service manager told me their examiner or GS-911 wont directly diagnose a faulty coil. It has to be done from the symptoms the fault generates. With good secondaries the engine should run when a primary is disconnected. if it stops firing on that side the secondary has probably failed. Secondaries are handed but can be swapped left-right for testing.

The coil resistance test figures are given somewhere in this forum. You will need long insulated probes and a (very) steady hand or a spare connector with bare wire ends to properly test the coil resistances.

NO also said that when one coil fails the other will following very soon. Both of my primaries went completely titsup within a few miles of each other.

I believe that low cost car stick coils (three pin type) could be used on the secondaries. HT leads would be needed but the coils could be placed out of the weather. The winding resistances will need to be in the same range as the BMW coils.