Engine cuts-out on idle throttle

[eric_cranston]

Hi all,

This is my 1st post on here, and I have a problem. :-( I wonder if one of you guys would point me in the right direction?

I have a 2008 GS, done about 38000 miles from new. The engine just won't start on an idle throttle. I can get the engine to start and run if I keep the throttle open. As soon as I let go of the throttle grip the engine cuts out. I have changed the notoriously unreliable fuel pump controller to no avail. When I turn the key I hear the fuel pump being 'primed'. (I think that's the correct term.)

Apart from a leaky rear suspension, which I replaced, have had no other problems.

Any pointers would be great.

Thanks.

 

[Deleted account 190920001]

Can you hold a normal idle speed with the throttle? If you can then first place I would be looking are the idle syncro's on each throttle body. Not sure if one being stuck would kill the engine mind you so it could be a bigger problem. A GS911 or dealer would be able to diagnose these very quickly.
If you cant hold a normal idle on the throttle then it could be a number of things but if it runs ok other than the low end then maybe look for air leaks between the throttle bodies and engine and the caps on the take-offs for vacuum gauges.
The throttle position sensor would be worth looking at as well although I would expect there to be issues elsewhere in the rev range as well.
Does it run fine other than at idle?

 

[ThorH]

Not sure if this is just BS or not, but I have seen this somewhere:

-Turn ignition to On position.

-Slowly turn throttle from stop to full open and then back to stop. Do this 2 times. This sets the TPS (Throttle Position Sensor).

Does anyone know if there is a hint of thruth in this? At least it doesn´t cost or hurt...

 

[Beemerman59]

Not sure if this is just BS or not, but I have seen this somewhere:

-Turn ignition to On position.

-Slowly turn throttle from stop to full open and then back to stop. Do this 2 times. This sets the TPS (Throttle Position Sensor).

Does anyone know if there is a hint of thruth in this? At least it doesn´t cost or hurt...

Yes, but you do it 3 times then turn the ignition off. Then its good to go.

 

[Mav]

Can you hold a normal idle speed with the throttle? If you can then first place I would be looking are the idle syncro's on each throttle body. Not sure if one being stuck would kill the engine mind you so it could be a bigger problem. A GS911 or dealer would be able to diagnose these very quickly.
If you cant hold a normal idle on the throttle then it could be a number of things but if it runs ok other than the low end then maybe look for air leaks between the throttle bodies and engine and the caps on the take-offs for vacuum gauges.
The throttle position sensor would be worth looking at as well although I would expect there to be issues elsewhere in the rev range as well.
Does it run fine other than at idle?

It could also be the Lambda sensors... When mine went, it would seem pretty much fine on the power just struggle on the tickover. One of the telling signs was running rich.

HTH

 

[philhunt88]

just got my gsa back form bmw today i mentioned that i had this problem a couple of times and it was a lamba sensor, fixed under warranty

 

[eric_cranston]

Can you hold a normal idle speed with the throttle? If you can then first place I would be looking are the idle syncro's on each throttle body. Not sure if one being stuck would kill the engine mind you so it could be a bigger problem. A GS911 or dealer would be able to diagnose these very quickly.
If you cant hold a normal idle on the throttle then it could be a number of things but if it runs ok other than the low end then maybe look for air leaks between the throttle bodies and engine and the caps on the take-offs for vacuum gauges.
The throttle position sensor would be worth looking at as well although I would expect there to be issues elsewhere in the rev range as well.
Does it run fine other than at idle?

Thanks for the advice guys. Much appreciated. Will try everything here and report back.



Mark

 

[eric_cranston]

Thanks for this. I have tried the TPS reset procedure to no avail. Looks like I will have to invest in a GS911 or be held by the nads by a BMW dealer Will report any result here.

 

[eric_cranston]

Can you hold a normal idle speed with the throttle? If you can then first place I would be looking are the idle syncro's on each throttle body. Not sure if one being stuck would kill the engine mind you so it could be a bigger problem. A GS911 or dealer would be able to diagnose these very quickly.
If you cant hold a normal idle on the throttle then it could be a number of things but if it runs ok other than the low end then maybe look for air leaks between the throttle bodies and engine and the caps on the take-offs for vacuum gauges.
The throttle position sensor would be worth looking at as well although I would expect there to be issues elsewhere in the rev range as well.
Does it run fine other than at idle?

No I cannot seem to hold idle speed. The exhaust gases seem to smell of petrol a bit so I'm thinking the engine is running rich so it could be the lambda sensor(s) as someone suggested in this thread. I'm going to get a GS9111 to diagnose.

Thanks

 

[fizzer]

if it is a lamba sensor i got one spare in the shed if you want it ,i had one go faulty and i changed the pair ,knackerd one in the bin .
£30 posted if you want it.

 

[Roymondo]

Does your bike have the onboard computer with oil level function? Does said oil level function work reliably? If not, I'd put money on the throttle position sensor being the culprit.

 

[Deleted account 190920001]

Does your bike have the onboard computer with oil level function? Does said oil level function work reliably? If not, I'd put money on the throttle position sensor being the culprit.

Can you expand on what the oil level function has in connection with the TPS?

 

[hatzyian]

Check out this post, slightly different, but problem was one Lamda sensor. Take them out and see if one is black. That side is the problem.

http://www.ukgser.com/forums/showthread.php?t=302638