Throttle body and ICV question

[Chris_D]

I'll be taking the throttle body and ICV off my M54 engine today in order to inspect and clean as I had a problem a couple of days ago where on starting the car the engine 'pulsed'. Had to call recovery guy who reset the fault and managed to get home.

Have another thread going in relation to this http://www.z4-forum.com/forum/viewtopic.php?f=3&t=90194 but thought I'd make this thread in the event someone does a specific search on this 'throttle body' topic and not my own tale of woe! Got some useful advice already in that thread. Will update that thread with info from here if conclusive. Apologies in advance if duplicated info is frowned upon here..

OK, my question is why shouldn't I move the butterfly or flap of the throttle body once it's off the engine as a couple of people have suggested? Is it linked to a sensor that will throw out a calibration or reference setting from the fly-by-wire system? That would make sense if so, but what if I accidentally rotated it a little during the cleaning process?
Bit worried I'll cock it up and cause a bigger problem. I'm not a mechanic, but am keen to get my hands dirty and save a few quid doing my own maintenance.

Intake hoses removed and I'm down to the throttle body. Just waiting for a lower intake boot to arrive and will then take off the throttle body and ICV.
I can use brake cleaner to clear out the ICV right? Or should I just use the carb cleaner as with the throttle body?

 

[Machine monkey]

I am not going to stand up and say that moving the flap wont damage anything. But i cant see how it is going to do any damage.

I have had multiple replacements getting to the bottom of my problem. I have checked the operation on every one before fitting. On my damaged body's it was very obvious that something was wrong as the flap felt like it was not engaging the little gears inside the sealed unit that drive it. Where as on the new one you could feel resistance from the motor. You could also hear little plastic gears rattling around inside. If you have that the body is done for. If not it may be fine.

In all cases after checking the flap movement the new body has gone on and worked fine no resetting or codding needed just a straight swap.

 

[Chris_D]

Ok good to hear MM, thanks for sharing ur experience.
Both ICV and throttle body are out and as expected, pretty filthy!
There's more sooty crud in that ICV than me nana's open fire chimney and there's more varnish on the inside of that throttle body flap than my good ladyfriend Laura lashes on her fingernails! :lol:
Carb cleaner and brake cleaner comin tomorrow for a good cleanup.

I think all the scaremongering about not moving the flap of the TB prob relates to potential damage you could do from effecting a force on it from a non-design source and having 20 years of design-engineering under my belt I can understand that completely. If the resultant motion of the flap snakes back to gears, actuators etc then its a good idea to not flap about with the flap!

Rotating the ICV along its longest axis reveals that the element inside is a bit 'sticky' so maybe this is where i was getting the 'pulsing at startup' issue.

Any thoughts on the condition of that TB anyone? Just needs a good clean out with carb cleaner?

 

[G-A-R-Y]

You will need to replace the orange throttle body gasket, available from main agents. It's a use once only to negate air leaks.

 

[Chris_D]

You will need to replace the orange throttle body gasket, available from main agents. It's a use once only to negate air leaks.

Thx gary. Got one on order but i dont think its as absolutely necessary as is made out tbh. The design suggests that if its in good condition there is between 1-1.5mm 'play' on tightening. More than sufficient to provide leak-tightness.

I've dealt with gaskets for alpha and gamma glass windows in the nuclear industry where leak-tightness reigns supreme ofc and i feel confident that the throttle body gasket would be capable of multiple use if in good condition.

Btw, is that u in ur avatar? What kind of bike u roll with?
Keen cyclist myself and managed to break the zeds cherry carrying my own bike to Valkenberg recently...

 

[G-A-R-Y]

You will need to replace the orange throttle body gasket, available from main agents. It's a use once only to negate air leaks.

Btw, is that u in ur avatar? What kind of bike u roll with?
Keen cyclist myself and managed to break the zeds cherry carrying my own bike to Valkenberg recently...Photo 26-08-2016 14 23 22.jpg

A carbon Giant from my TT days, just a roadie now.

BTW, new joint is surprisingly thicker and is directional.

 

[Scooba_Steve]

While I agree it's probably not absolutely necessary to replace the gasket every time, for the money involved, and the potential age of originals I did so anyway.