Removing airfeed pipes to throttle bodys

Bendy toy said:
Not quite sure what you’ve tested.
Have you run it with both secondary coils unplugged got it fully hot and then done the primary tests?

However mine with secondary coils running would drop the revs slightly whichever primary was disconnected it turned out that both primary coils were failing.
What’s the chance of that? They often fail in pairs according to BMW dealer.
Mine actually smelled burnt. Not knowing how they are supposed to smell I carried on. They new ones have done 25K no funny smells.
Click to expand...

I'd disconnected the secondarys and did everything from cold

Once warm it wont idle at all it just dies if you take your hand of the throttle

Even reconnecting the secondarys at this stage it still wont idle

If i leave it for about 30 mins to cool, and restart (all connected) and unplug the primarys, you

can hear / feel a slight drop in rpm as

you make / break the primary connections side to side but nothing that jumps out on you.
 
See if you can borrow some primary coils. New ones are £90 each though I suspect you’ll need a pair.
With both secondary coils disconnected it should run on one cylinder when one primary is also disconnected. If the one remaining coil is faulty the engine will stall.
The fact it’s worse when hot suggests a coil problem.
Stalling below 1500 revs with only one side firing is quite likely as its a big lump to keep going
 
Dropped the secondary plugs today for a gander ..

They came out ok, so i suspect they they have been out at previous services, which is good ..

Dificult to say whether there ok, as the last runs i did was with them disconnected.

Bit of a mixed bag on the plug condition ,

They went from black and sooty to a normal light brown with some whitish deposits

right on the top of the centre electrode and side electrode.

I can post pics if that makes any difference...

just a thought .. would iridium plugs help the low speed rough running?

some people have said it helps??
 
If you can have a look at the crank sensor and its connections(picture). Not found it on the GS but had very similar problems on cars in the past. When engine running slow would not generate a strong enough pulse, if any, to trigger the ignition. Poor/shitty connection or wire damage would give you the intermittent problem, may be worse in the wet. Dont trust a continuity test. A single strand of wire will show ok but will not flow the current needed. If you have a multi meter can test easy enough. resistance then crank engine and should get a healthy pulse. Just a thought have you taken the multi plug from the ECU? all ok no crap on pins or sockets?
 

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Ted said:
If you can have a look at the crank sensor and its connections(picture). Not found it on the GS but had very similar problems on cars in the past. When engine running slow would not generate a strong enough pulse, if any, to trigger the ignition. Poor/shitty connection or wire damage would give you the intermittent problem, may be worse in the wet. Dont trust a continuity test. A single strand of wire will show ok but will not flow the current needed. If you have a multi meter can test easy enough. resistance then crank engine and should get a healthy pulse. Just a thought have you taken the multi plug from the ECU? all ok no crap on pins or sockets?
Click to expand...
Not looked at electrics in detail yet.

Problem seems to be either no fast idle from cold start unless a bit of throttle is given / held.

and then once warm it wont run on closed throttle, just dies. but on a restart will idle fine for a bit until i drive it for a bit then it

starts the symptom again
 
Assume you have checked for air leaks between the throttle bodies/injectors and heads. Little rubber caps over balance ports not cracked or loose. Can spray a bit of WD40 and if you get a change in engine note that need sorting.
Sounds like the stepper motors that control idle not working correctly or sticking. GS911 should be able to cycle through the steppers see if sticking. Then its a matter of working out what controls the motors, what tells them to go to idle position. Crank sensor, TPS are main ones. When you close the throttle from high engine revs the fuel is cut off, injectors remain closed till engine rev drop to a preset rev range then switches on the fuel again so engine doesn't stall. :thumb
If the TPS has a crappy contact or a dead spot as it closes will get the same symptoms. But as it seems to fix itself pointing towards a connection somewhere.
Loads of Youtube info on how to check, strip and clean the TPS. Checking the coil packs and so on. Sometimes just simply unplugging items and reconnecting them cures the problem.
Here's a link to checking the TPS ( note list of symptoms are everything you mentioned)
http://www.ukgser.com/technical/nick/Throttle-Position%20Sensor%20(All%20BMW%20models,%20'04%20on)%20V1.0.pdf
The TPS is pricey from the dealers. Nip next door the the car department. Same as on most of the cars and quarter the price;)
 
Ted said:
Assume you have checked for air leaks between the throttle bodies/injectors and heads. Little rubber caps over balance ports not cracked or loose. Can spray a bit of WD40 and if you get a change in engine note that need sorting.
Sounds like the stepper motors that control idle not working correctly or sticking. GS911 should be able to cycle through the steppers see if sticking. Then its a matter of working out what controls the motors, what tells them to go to idle position. Crank sensor, TPS are main ones. When you close the throttle from high engine revs the fuel is cut off, injectors remain closed till engine rev drop to a preset rev range then switches on the fuel again so engine doesn't stall. :thumb
If the TPS has a crappy contact or a dead spot as it closes will get the same symptoms. But as it seems to fix itself pointing towards a connection somewhere.
Loads of Youtube info on how to check, strip and clean the TPS. Checking the coil packs and so on. Sometimes just simply unplugging items and reconnecting them cures the problem.
Here's a link to checking the TPS ( note list of symptoms are everything you mentioned)
http://www.ukgser.com/technical/nick/Throttle-Position%20Sensor%20(All%20BMW%20models,%20'04%20on)%20V1.0.pdf
The TPS is pricey from the dealers. Nip next door the the car department. Same as on most of the cars and quarter the price;)
Click to expand...

Interesting article , many thanks :)

Symptoms are very similar to mine in just about all respects, apart from the hot non idle.

I have a spare TPS in front of me as as i'm typing this ;)

I'll whip mine off later and check the electrical values before i open it up
 
Mine has s reluctant/slow stepper on the righthand side. I’ll eventually get it sorted but it never causes any problems. But if both were playing up eg due to other sensor signals the bike would refuse to run below 1500 rpm. Unplug the steppers and you’ll see what I mean.
 
Well i pulled both TPS units apart -

The one i picked up on here, and the on off the bike ..

The one i picked up on here looks relativley new so to speak,

the carbon tracks look ok with no banding or worn spots.

The one taken of the bike, looks like its done a gazillion miles

lots of stop start lines and looks worn.

Funny thing neither of them show the values given in the article referred to by a

previous poster.

The one of the bike, looked like it was wet inside, but this may be dielectric grease

Too cold to go and refit it tonight ;)
 
Mac One said:
Any progress ??
Click to expand...

Not yet, cleaned both TPS units the SH one looks in better condition internally than the one of the bike lol

I will pop them back on the bike tommorow and see what happens -- assuming it will start in the artic apoclypse we seem to be

not having lol
 
Update

Right, a quick update

Refitted the new (sh) tps and did the 3x throttle open and waited 5 mins started the

bike, and the tickover is high

2K as opposed to 1.1K

Looked in GS911, but there is no BMSE function to recalibrate the TPS hmmm

turned the bike off and restartd it, and it dropped to about 1.4k and then droppe

again as the bike got warm.

Turned it off and went and got my gear on .

Hooked everthing up , started the GS logging and went to do my gear adaptions

i did a 15 mile round trip - home - work work - home.

I pulled over a few times and let the throttle shut under it's own steam, it ticked

over well at about 1.1k

Getting home i came up the road, and pulled in the clutch letting the throttle shut

off, again it ticked over normally

No misfiring or jerkiness was felt at all during the journey,

I'm going to attempt going to work on it tommorow

(Typical though, i cant find the GS log that was running when i went out for the trip )
 
Just check your TPS is giving the correct readings. With the 911 connected you can look at the realtime values. With engine not running look at the output from the TPS. Should go smoothly from zero to 100% as you twist the throttle open.
 
Kenny Rodkiss said:
Just check your TPS is giving the correct readings. With the 911 connected you can look at the realtime values. With engine not running look at the output from the TPS. Should go smoothly from zero to 100% as you twist the throttle open.
Click to expand...

But the problem wasn't accelerating... It was after running perfectly normally and then at idle dying . I've mentioned previously (and via PM a while ago :D) that TPS problems often don't show up as faults on a 911.
 
Just a thought that if his was giving the wrong readings that it would adversely affect the tickover. He said the one his bike looked wet inside! ?
 
Kenny Rodkiss said:
Just a thought that if his was giving the wrong readings that it would adversely affect the tickover. He said the one his bike looked wet inside! ?
Click to expand...

It did, but on closer examination appeared to be grease or similar -
I cleaned the plug with contact cleaner and reassembled.

Started it this morning, straight away to a steady idle

Run to work was fine this morning. A couple of times i thought it was going to die, but it just held at about 1.1k rpm.

I'll run it for the rest of the week and see what happens
 
Steptoe said:
But the problem wasn't accelerating... It was after running perfectly normally and then at idle dying . I've mentioned previously (and via PM a while ago :D) that TPS problems often don't show up as faults on a 911.
Click to expand...

Indeed, i'll go back through my saved logs, but as you say, i bet i dont see anything untoward
 
As Steptoe has already said TPS faults don't always show even on the dealer's test equipment.

Your symptoms match those I had some while back, which foxed a French BMW dealer for a day.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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