Sticking throttle

[john henson]

Hi all,
Just taken my Z3 2.0 out and revs are all over the place .put clutch in and revs climb .any ideas please

 

[t-tony]

Get a code reader connected and see what faults are stored. My money is on inlet camshaft position sensor, or, a very bad induction leak. Has the fuel consumption recently gone sky high?

Tony.

 

[john henson]

Thanks Tony will get those points checked.havent really noticed higher mpg.when I change gear the revs go up in-between changes as high as 5000rpm

 

[t-tony]

What year is your Z3, if it’s pre ‘99 it could have a throttle cable, but if I’m correct 2000 on we’re “fly by wire”

Tony.

 

[john henson]

It's 2001 2.0.when I had finished the run it was ticking over at 2500 rpm.switchen engine off and when I switched on again all was o.k at 700 rpm

 

[t-tony]

Definitely no throttle cable then. Air leaks most likely culprit. But do get a code reader on it. Where are you located John.
?

Tony.

 

[john henson]

Coventry.going to check with my local garage I use.i know they have a fault finder that plugs into the ecu.

 

[t-tony]

The connector under the dash only ”talks” to the engine and Auto. Gearbox so it may be all you need. Anything else and you’ll need to connect to the circular connection under the bonnet which requires an adapter cable.

Tony.

 

[john henson]

Thanks Tony .Uv been a great help.much appreciated

 

[t-tony]

Hope I have helped John, please ask if I can do any more and please keep us posted on your progress.

Tony.

 

[john henson]

Will thanks again

 

[NZ00Z3]

If you have a 2.0L Z3, then you have the M52TUB20 engine, with an accelerator cable. The throttle body is called an MDK and has both the pedal and throttle position sensors in it.

The rev's jumping/sticking at those high values tend to indicate a throttle body problem. The engine computer (DME) trouble codes will tell you if its a MDK problem.

I'm currently in the middle of writing a DIY (mini novel) on how to diagnoses and fix the MDK. Got my 2.0L Z3 back together yesterday and the MDK is good to go.

Whoever gets to do the diagnosis needs to have a good scanner with BMW software. INPA is very good. It needs to give the freeze frame data for each BMW special MDK fault code. That is where the real clues on how to fix the MDK lie.

Hope the MDK can be repaired, they are expensive to buy new.

 

[john henson]

If you have a 2.0L Z3, then you have the M52TUB20 engine, with an accelerator cable. The throttle body is called an MDK and has both the pedal and throttle position sensors in it.

The rev's jumping/sticking at those high values tend to indicate a throttle body problem. The engine computer (DME) trouble codes will tell you if its a MDK problem.

I'm currently in the middle of writing a DIY (mini novel) on how to diagnoses and fix the MDK. Got my 2.0L Z3 back together yesterday and the MDK is good to go.

Whoever gets to do the diagnosis needs to have a good scanner with BMW software. INPA is very good. It needs to give the freeze frame data for each BMW special MDK fault code. That is where the real clues on how to fix the MDK lie.

Hope the MDK can be repaired, they are expensive to buy new.

 

[john henson]

Thankyou for this.much appreciated.

 

[Mike Fishwick]

Sounds like a clutch switch problem - I had this problem with the rpm climbing during a gear change, and it was fixed by replacing the switch. Try disconnectiong the switch and see what happens.

 

[john henson]

Thanks mike.can you tell me where it's located

 

[Mike Fishwick]

at the top end of the clutch pedal.

 

[john henson]

Thanks much appreciated