Lumpy idle and EMC light

[petrolhead88]

I had an issue with my car this morning, I've made a video below. Pressing the throttle doesn't do anything either:

https://youtu.be/SEX60k6YE1I

Has anyone ever experienced anything similar?

 

[TomK]

Quite likely one of your tps (throttle position sensors) has gone.
There are 2 in the engine bay and one under the pedal.
Get the fault codes read and go from there.

 

[Scooba_Steve]

Could be many things, you need to read the codes, either yourself (buy a cable), at a garage (costs more than the cable), or via breakdown service (often free).

Without the codes any suggestions are pure guesswork (though may be correct) and can lead to expensive guesswork.

 

[Chris_D]

This looks EXACTLY like what i experienced recently- idle oscillation and no throttle response.
Machine Monkey here said he'd had this too and advised to replace the throttle body so i did and the idle problem was solved. However, it may have spawned a few more problems as i'm now dealing with a leaky camcover gasket and a failed ccv system.
I bought a cheap 2nd hand tb from ebay to test MM's theory but i might just invest in a brand new one once everything else is sorted.
It COULD be your tb but as others have suggested get the obd scanned.
I invested in the carly system after getting hold of the wireless obd dongle from a forum member- works great for diagnostics as well as recoding.
Thread for tb issue:
http://www.z4-forum.com/forum/viewtopic.php?f=3&t=90194

Good luck!

 

[TomK]

Chris, it is unlikely to be your issue with the TB since the S54 in the M doesn't use one like this it has 6 individual tb's.
I had an almost identical issue to the op and it proved to be the tps at the front of the engine, however as said get the fault codes read before doing anything.

 

[Chris_D]

Chris, it is unlikely to be your issue with the TB since the S54 in the M doesn't use one like this it has 6 individual tb's.
I had an almost identical issue to the op and it proved to be the tps at the front of the engine, however as said get the fault codes read before doing anything.

6 tb's?? Crikey
How much do they cost?
For me thats just like increasing ur potential chances of a tb failure 6-fold!

 

[TomK]

No idea, never heard of an itb failing on an S54, they are purely mechanical.
The actuator that controls all of them can fail though and that is quite expensive.
New TPS is around £100 iirc op.

 

[Chris_D]

Agree its more likely to be tps as its prob the inbuilt component of my tb that failed.
However, all mechanical systems can fail and usually have a prediction-modelled MTTF. It's an integral part of product lifecycle design philosophy.
I.e nothing lasts forever.
Except maybe perhaps the fekin blob of chewing gum some derty bastid spat out in front of my front door last week! Tried everything but an angle grinder. It wont shift.

 

[petrolhead88]

I'm trying to get the codes read without being fleeced £60 to 'plug the computer in'. I'll report back once I know, thanks for the responses so far

 

[TomK]

A friendly indy should do it for a LOT less, only takes 2 minutes really.

You could just buy yourself one of these http://www.ebay.co.uk/itm/Mini-OBD2-ELM327-V2-1-Bluetooth-Car-Scanner-Android-Torque-Auto-Scan-Tool-OBD-II-/231635380002?hash=item35ee8b6722:g:d44AAOSw3ydVtzCS
and download the Torque app for a couple of quid. This will enable you to read and clear codes amongst a bunch of other stuff. Very simple.
Alternatively, buy an OBD to usb cable and the BMW software (usually about £25), you'll ideally want to run it on an old XP laptop.
Much more complicated but a lot more useful for other things.

ETA: where are you located? Perhaps a local member could help you out...

 

[petrolhead88]

I called the RAC out to have it recovered to an Indy.
However, the car started up fine with a normal idle, although the engine light was still on. So the RAC man reset the faults and the light hasn't come back so far (done 100 miles since) so I assume it is now ok. I will keep an eye on it in case it comes back.

The fault logged was Throttle position adaption error and Throttle Unit, Internal fault.

 

[Chris_D]

Good to hear!
Although i'd be booking it into an indy in any case as it sounds like tps or associated is on the way out.

 

[goon]

get this on mine regularly, real pain.

 

[TomK]

I'd put good money on it being one of the TPS'. Since there are 3 and they are all the same it would make sense to carry one as a spare in your shoes (or any of us for that matter) I reckon. It could also be a problem with the throttle actuator though (which one of the TPS' hangs off) accessible underneath the airbox.
Glad to hear your moving in any case