Z4 Fluctuating revs, engine rattle and misfire?

Lytesben · Post by **Lytesben** » Wed Mar 15, 2017 8:38 pm

So my first week of Z4 ownership has not gone well at all. Got in the car yesterday morning and started it up fine, then realised the revs were fluctuating. It then sounded like it had a bit of a misfire and the EML came on.

I thought maybe it might be the MAF at first but unplugging that may almost no different if maybe a slight improvement. I've plugged it in and it has thrown up the following codes:

P0102 - Mass or volume air flow - circuit low input

P0113 - Intake air temperature - circuit high input.

On starting it this evening it is again fluctuating revs and there is a rattle coming from the top of the engine

[youtube]https://youtu.be/PPu2UVA17_w[/youtube]

Anyone able to help point me in the direction of what's wrong? It's a 2004 Z4 2.5. Starting to wish I never bought the car!

Smartbear · Post by **Smartbear** » Wed Mar 15, 2017 8:46 pm

If you've only had it a week the first thing I'd suggest is returning the car, did you buy from a garage?
Rob

Lytesben · Post by **Lytesben** » Wed Mar 15, 2017 8:51 pm

Unfortunately I bought it privately so don't really have much of a come back.

Ducklakeview · Post by **Ducklakeview** » Wed Mar 15, 2017 8:56 pm

From the symptoms, I'd say VANOS... Could simply be a sticky or disconnected solenoid, or could be the seals..

Mike

Lytesben · Post by **Lytesben** » Wed Mar 15, 2017 9:36 pm

Ducklakeview wrote:From the symptoms, I'd say VANOS... Could simply be a sticky or disconnected solenoid, or could be the seals..

Mike

I'm a complete newbie to BMWs, is VANOS expensive to repair? I'll probably be booking it into my local garage to have them look at it.

Smartbear · Post by **Smartbear** » Wed Mar 15, 2017 9:42 pm

Ducklakeview wrote:From the symptoms, I'd say VANOS... Could simply be a sticky or disconnected solenoid, or could be the seals..

Mike

Hmm, would that have flagged up those fault codes though?
Rob

jabber · Post by **jabber** » Wed Mar 15, 2017 10:00 pm

Check the disa valve if you unplug the cable see if the rattle stops do a search on youtube for bmw disa

Ducklakeview · Post by **Ducklakeview** » Wed Mar 15, 2017 10:33 pm

Smartbear wrote:
Ducklakeview wrote:From the symptoms, I'd say VANOS... Could simply be a sticky or disconnected solenoid, or could be the seals..

Mike
Hmm, would that have flagged up those fault codes though?
Rob

Those will be from him disconnecting the MAF? I presume the MAF also reads the inlet air temp.

Sounds like a much noisier version of the sound I heard momentarily from mine at idle last week, just as it hit 60k, after me posting abouth thinking of doing the VANOS too...

Mike

Silverzedtom · Post by **Silverzedtom** » Wed Mar 15, 2017 11:04 pm

Although a pain in the backside try not to get too down about it. When it's up and running as it should be you will fall in love with it.

whilst a slight rattle from the valve lifters is a common problem found on Zeds it shouldn't sound anything like this. If you can't diagnose it with the intention of repairing it yourself I would get it into an Indy asap.

Fyi: A slight valve lifter rattling noise is said to be "harmless" and will die Down after a few long drives. Hope it's sorted soon

Lytesben · Post by **Lytesben** » Sat Mar 18, 2017 8:54 pm

So got around to removing the disa valve this morning to have a look at the state of it. Took it out and it looked absolutely fine, put it all back together and it now seems to run perfectly again and no rattling.

So I'm guessing that something was wrong with it and taking it out and refitting has fixed it

Simon Blythe · Post by **Simon Blythe** » Sat Mar 18, 2017 9:07 pm

Did you try rotating the flap on the disa valve? If there play in it then it will "chatter" could also cause the car to bounce when you pull away at low revs.

Simon Blythe · Post by **Simon Blythe** » Sat Mar 18, 2017 9:09 pm

Lytesben wrote:So my first week of Z4 ownership has not gone well at all. Got in the car yesterday morning and started it up fine, then realised the revs were fluctuating. It then sounded like it had a bit of a misfire and the EML came on.

I thought maybe it might be the MAF at first but unplugging that may almost no different if maybe a slight improvement. I've plugged it in and it has thrown up the following codes:

P0102 - Mass or volume air flow - circuit low input

P0113 - Intake air temperature - circuit high input.

On starting it this evening it is again fluctuating revs and there is a rattle coming from the top of the engine

[youtube]https://youtu.be/PPu2UVA17_w[/youtube]

Anyone able to help point me in the direction of what's wrong? It's a 2004 Z4 2.5. Starting to wish I never bought the car!

Disa valve

Lytesben · Post by **Lytesben** » Sat Mar 18, 2017 9:13 pm

Simon Blythe wrote:Did you try rotating the flap on the disa valve? If there play in it then it will "chatter" could also cause the car to bounce when you pull away at low revs.

I did indeed, it springs back correctly and no play in it. That's why I put it all back together thinking it wasn't that. Now seems to be running absolutely fine.

One of the air pipes may have been loose as it came off way to easy when I was trying to get at the torx screw so put that back together properly and tight so guess it might have had a slight air leak as well?

Simon Blythe · Post by **Simon Blythe** » Sat Mar 18, 2017 9:19 pm

Z4-forum.com

Z4-forum.com