Uh oh. Bennys' first tantrum! WAYHAAAY We're back in business! :) EDIT: 2000 mile update.

[Machine monkey]

The throttle body and DISA valve are completly different parts. The DISA Valve is in you intake plenum and opens and closes to give maximum Torqe. The throttle body is what controls air in to the engine.

 

[Chris_D]

The throttle body and DISA valve are completly different parts. The DISA Valve is in you intake plenum and opens and closes to give maximum Torqe. The throttle body is what controls air in to the engine.

Thx MM, yes I just did a bit of further digging and realised they are totally different parts.
Will be checking that and other the things over the coming days. If I can't crack it will just get the local indie to take care of it.
Thx for sharing your experience - it does sound like it could actually be the same prob as you had if not exactly the same!

Will keep this thread updated re progress if it helps others....

 

[Chris_D]

O dear its never nice when our cars go wrong.
The p1633 code and the hunting for revs sounds like what i have had issues with previously. Also the fact that the car was re set and then once switched off did the same thing. Now i am not saying its the same thing but is 100% worth looking at. If its the same as mine its an easy fix but not cheap. Basically you will need to buy a new throttle body (i have had pattern and BMW ones and there is no difference)

I have had to put 3 of them on my car and the reason they all died (i think i am at the bottom of the problem) Was a dodgy earth. the throttle body is just a flap that opens and closes relative to pedal position. Its controlled by a voltage. lets say 1 volt fully open 0 volts fully closed. If there is fluctuating volts the flap could be fully closed or open. And then it may try opening of closing further. This then causes the little plastic gear that drives it to strip its teeth. When this happens the flap then cant fully close like needed on start up and the car dose not know its position and then runs rough.

If you have the time. Try taking the inlet pipe off manually close the throttle flap with a long screwdriver. Replace the pipe work and reset the codes. If it starts up and runs and drives. But then when switched off runs rough. I would 99% say swap the throttle body problem fixed.

This what i used last time.
http://www.eurocarparts.com/ecp/c/BMW_Z4+Roadster_3.0_2003/p/car-parts/fuel-and-engine-management/engine-parts/throttle-body-service-kit/?422110021&1&5e84c67d26b5099c7719be528fd31a6305ab5065&000329

Just spoke to my local indie MM, he thinks this is a good idea to just give ur suggestion a try out. Will let u know how it goes.
Sun's crackin the flags over here in holland today and i dont have a nice col shady garage. Gonna get sweaty!

 

[Chris_D]

Might have found the culprit. The holiest of all holy lower intake boots!
It's in a frankly unbelievable state and would explain the chirruping noises I've been hearing.
Obviously the loss or insufficient vacuum has given rise to other problems.
Biking down to stealer for replacement once I find the part number. I've seen a fair few Z4's parked up in their service area so banking on them having this part.
Will give the DISA a clean as it's covered in dust. It's in really good nick - plenty of suspension in the valve actuator when I place my finger over the air inlet hole, no play in flap and seal seems ok albeit a bit flat obviously. Might order a new seal in any case and fit later...

Anyone know the part number for the lower intake boot section as I can't seem to find it on realOEM?

 

[Machine monkey]

If after that has been replaced you still have the problem.
In the last picture you should be able to gain accesses to the throttle body flap through the big hole. Then re set and try starting if it runs fine but then not i would be thinking you still have a throttle body problem.

 

[ben g]

I had some rough running issues. It was almost as of someone had stuck a potato up the exhaust. Massive vibrations through the car on idle, it felt like I had a 7.0 v8 under the hood.

Replaced that lower intake hose, replaced the disa and then finally I removed and cleaned my ICV. This completely stopped the rough running. My ICV was so caked up in soot and grease that it was stuck in position and the valve was unable to move. I cleaned it with brake cleaner and it has been fine for almost a year now.

 

[Chris_D]

If after that has been replaced you still have the problem.
In the last picture you should be able to gain accesses to the throttle body flap through the big hole. Then re set and try starting if it runs fine but then not i would be thinking you still have a throttle body problem.

I tried to move it with my finger MM bit it wouldnt budge. Didnt want to force it in case i broke or offcentred it.
Should it move freely about its centre axis? Or does it need a bit of a shove?
Is there a particular reset procedure that i should follow?

 

[Grumpyowl]

Might have found the culprit. The holiest of all holy lower intake boots!
It's in a frankly unbelievable state and would explain the chirruping noises I've been hearing.
Obviously the loss or insufficient vacuum has given rise to other problems.
Biking down to stealer for replacement once I find the part number. I've seen a fair few Z4's parked up in their service area so banking on them having this part.
Will give the DISA a clean as it's covered in dust. It's in really good nick - plenty of suspension in the valve actuator when I place my finger over the air inlet hole, no play in flap and seal seems ok albeit a bit flat obviously. Might order a new seal in any case and fit later...

Anyone know the part number for the lower intake boot section as I can't seem to find it on realOEM?

Photo 30-08-2016 14 49 31.jpg


I have recently just done (as a precaution) the Disa valve upgrade.
my boot looked just like yours, had to wait 24 hrs for delivery from dealer. While it was just as bad as yours the car through upno fault codes,
if yors is the same as mine this may not solve yor problems.

 

[Chris_D]

I'm hoping to get lucky with this one Grumpy.
I managed to drive all the way home 30m without issue once the recovery guy reset the fault. So hoping this relateonly to the leaky boot and lack of vacuum.
Part comes Thursday but in the meantime i'll have a crack at cleaning throttle valve and icv...

 

[Mike6]

Hope all is well but going back to that 'battery could be on way out' suggestion I do understand that car can throw all sort of error codes if battery is of incorrect spec. If all is not fixed with new intake hoses I would therefore check that honda battery against the BMW spec.

 

[Chris_D]

I had some rough running issues. It was almost as of someone had stuck a potato up the exhaust. Massive vibrations through the car on idle, it felt like I had a 7.0 v8 under the hood.

Replaced that lower intake hose, replaced the disa and then finally I removed and cleaned my ICV. This completely stopped the rough running. My ICV was so caked up in soot and grease that it was stuck in position and the valve was unable to move. I cleaned it with brake cleaner and it has been fine for almost a year now.

Will try to removand clean icv. Easy job? Any guide threads here u can point me in direction to? Had a quick look on uface but no removal guides, only cleaning...

 

[Chris_D]

Hope all is well but going back to that 'battery could be on way out' suggestion I do understand that car can throw all sort of error codes if battery is of incorrect spec. If all is not fixed with new intake hoses I would therefore check that honda battery against the BMW spec.

Thx mike, forgot to check battery in haste to get lower boot ordered. Fekin Ekris BMW in Utrecht made me bike down there just to order and pay for the part. Whatever happened to trust? Pff. Mustve thought: dodgy english guy wants part but might forget about it.

In any case, i have one of those cool little suaoki battery starter things. If that's on 100% ready and i hook it up to terminals as well as existing battery it should replicate a new condition battery shouldnt it?

 

[Chris_D]

I should add that you need to check you earth readings. There is one in the engine bay on the passengers side. And then one by the batter in the boot. My boot one had funny readings and just needed cleaning. I took me at least 3 body's and 2 years to figure that out

How did u check that MM? With a multimeter?

 

[Machine monkey]

I should add that you need to check you earth readings. There is one in the engine bay on the passengers side. And then one by the batter in the boot. My boot one had funny readings and just needed cleaning. I took me at least 3 body's and 2 years to figure that out

How did u check that MM? With a multimeter?

Yes check from the battery terminal and the ground point under carpet at the right of the boot. It should read less than 0.5 ohms.

 

[Chris_D]

If after that has been replaced you still have the problem.
In the last picture you should be able to gain accesses to the throttle body flap through the big hole. Then re set and try starting if it runs fine but then not i would be thinking you still have a throttle body problem.

Was about to start cleaning process for throttle body and ICV when I noticed a very feint rattle inside the TB housing - like a very small piece of plastic has come loose. Ooer.
What would you do? The TB is a sealed unit isn't it, with no way to take apart and inspect?
Is there any way to test for operability while it's off the car? suspect not.
I think hardest way to test is to clean both TB, ICV replace everything including new lower boot and crank up. Suck it and see. A bit of a PITA as I'm not a mechanic and it took about 2 hours for me to strip down intake system but I presume you've been through all this mate?

Also, the plenum in the TB isn't perpendicular to the body - see pic. Is that normal? Like it doesn't close completely. Was in that position when on the car before removal.

 

[Machine monkey]

I think mate you have had the same problem as me. That rattling is the broken plastic gear. If its not closing fully then it wont run right. By all means put it all back with the other bits. But i think you will be needing new one. How did checking the earths go?

This really dose sound exactly the same as what i had. You can take it apart. You just cant get it back together well i couldn't.

 

[Chris_D]

I think mate you have had the same problem as me. That rattling is the broken plastic gear. If its not closing fully then it wont run right. By all means put it all back with the other bits. But i think you will be needing new one. How did checking the earths go?

This really dose sound exactly the same as what i had. You can take it apart. You just cant get it back together well i couldn't.

dammit- u reckon its a goner then? it should be fully closed/sealed 90degrees against the body when off the motor?
I just finished cleanin it. lol
what would you do? baz in a new one?

there's LOTS of resistance when u push the plenum and springs back to what feels like a datum location. surely a throttle body would never have to be fully closed/sealed?

 

[Machine monkey]

If there are little bits of plastic rattling around inside. And you have had the same symptoms as me with the car. I would say there is a good chance mate yes. No harm in sticking it back on and trying it? I would like to be wrong for your sake

 

[Chris_D]

If there are little bits of plastic rattling around inside. And you have had the same symptoms as me with the car. I would say there is a good chance mate yes. No harm in sticking it back on and trying it? I would like to be wrong for your sake

I'll whack it back on and see what happens. It's worth the 2 hours of skinning my knuckles rather than shelling out Eur250 for something I might not need.
Good practice anyhoo. It's like lego for grownups takin ur motor to bits!
:lol:

 

[Machine monkey]

2 hours!!! you will get it done quicker this time now you have done it once.