Juddering in first gear + engine light on

[Z4Tuga]

Hi all,

I seem to be faced with the first problem on my Z4 (less than a week of ownership ). It's a 2007 2.0 roadster.
I have some juddering when taking off in first gear. I've noticed this at the dealership when I did the test drive, and then leaving the dealership after purchase, but coming from a diesel car I always tought it was me not used to the clutch pedal or something. Plus, on the both occasions when the dealership owner was taking it out of the showroom he seemed to manage this fine, no juddering at all, so again just reinforced the idea that this could be me being a big newb!
However, it's the fifth time I've driven the car and the problem seems to persist (I like to thing that I would have tamed the beast by now). I have to rev it properly so I dont get this. All other gears however are perfectly fine.

In the meantime, driving to work this morning, the engine light came on. No noticeable loss of power or something, but I was in a town road so couldnt really push it to test it. Just before that it did 10 miles on the motorway and it was fine.

I know that regarding the engine light only a proper code reading will inform what it might be and I will try to do it this evening, but any thoughts on if the two problems might be related??

 

[Sidewaze Samm]

My advice - give it to the dealer to fix. We had a 2006 2.0 with 65k miles. EML came on after 100 miles and was intermittent after that. Also had that moving off issue you describe. After two months and several attempts by the dealer to fix it, the car went back to the dealer for a refund. Now happily driving a 2.5

Should have given the car back sooner - didn't as it was a 'nice' one - because the dealer is allowed to make a deduction for mileage driven. But there is no official guidance on rates for this, so the perfect scene for a ding-dong with the dealer!

2.0 engines are prone to issues, so get codes read (but not cleared) by an indy or forum member then give the dealer the chance to fix it, no more than twice.

Get it fixed quick or get rid.
Good luck

 

[mmm-five]

Juddering could simply be due to the clutch delay valve (CDV). Which slows the clutch action down...but also means you have to play with the bite point more carefully.

Seems to also happen more when it’s cold...probably due to the fluid being colder & hence thicker.

Other than that, the only thing I can think of is a dodgy DMF/clutch itself.

Take it back to the dealer and let him drive it with you as a passenger, and see if he does anything special/slower to move it off.

 

[ph001]

It will be the usual 2.0l emissions related issues that seem hard to resolve. Unfortunately the manifolds also have a habit of cracking which can lead to similar symptoms. But at least you have the dealer there to sort it out for you...if they can. Don't let them fob you off.

Out of interest, did you just fill it up with a different brand / grade of fuel by any chance?

 

[Z4Tuga]

Thanks for your feedback.
I'm going to have it serviced at some point this week by an independent specialist and I'm using your feedback to compose a list for him to get through, so any other suggestions are welcome!
Regarding the juddering, I get the impression that this morning was the worst I've had, so it being cold might be playing a part as suggested.
As for the petrol I've used, not sure what was there before purchase, but upon leaving the dealership I put £10 of 95 and just yesterday a full tank of 98.
Please keep any ideas/suggestions coming!

Obviously, following the service, any problems diagnosed/confirmed I will be taking it with the dealership as suggested.

 

[philbo909]

I would get the company you bought it off to sort out the eml before you pay to have it serviced

 

[Sidewaze Samm]

I would get the company you bought it off to sort out the eml before you pay to have it serviced

+1
Don't spend money on it til the issue is resolved

 

[Mike6]

And if you have it serviced before returning to dealer they will only claim someone else has fiddled with the car and they are not liable. Take it back, best advice anyone can give you.

 

[Z4Tuga]

Ok, quick update.
Obviously you were right and it didn't make any sense to service it first just to be accused of messing some sensor.
Took it to the dealership, described problem with the juddering (which in the afternoon seem to have improved) and explained on which circumstances the light came on. Mechanic at dealership reset the light and then had the car running for a good 20 minutes, revving it hard every few minutes. Light didn`t come back during this time. I was told that the error coming through on the reader was to do with catalytic converter. He asked me how much I had filed the tank and I explained that I did it until the pump gave me the sign that it was full. Also asked me what petrol did I use. I told him I used Costco Premium Unleaded, which apparently is 99 RON, the equivalent to Tesco Momentum and that before that had done £10 of normal unleaded at an Esso pump.
He then went on to tell me that nothing unusual was coming up on the readings after he had reset the lights. The only other thing he did was to change a parameter that according to him was set on 0, and it is supposed to be between 0 and 3. This was to do with the VVT and he set it a little higher. Because I mentioned that the juddering seemed worst in the morning he decided to keep the car overnight and will test drive in the morning to see what he gets.
What do you guys make of it? Should I be insisting on something in particular? I've read posts mentioning air in the deposit and how it could trigger these lights, and I'm assuming that`s why he's asking me how much petrol I had put in. Also, is 99 RON overkill and could it be causing the problem, given that it still had some 95 RON left in the tank?
Any thoughts welcome!

 

[Sidewaze Samm]

I can't answer your technical points. But I will say don't assume it's sorted until the car has been running right for a good length of time. There is no time limit to the dealer's liability. Keep detailed record of faults and all contact with dealer, until the issue is resolved one way or the other.
Good luck

As a point of interest, our 2.0 kept throwing codes for VVT and for throttle valve potentiometer (even though the dealer had fitted a new genuine throttle body)

 

[Z4Tuga]

I can't answer your technical points. But I will say don't assume it's sorted until the car has been running right for a good length of time. There is no time limit to the dealer's liability. Keep detailed record of faults and all contact with dealer, until the issue is resolved one way or the other.
Good luck

As a point of interest, our 2.0 kept throwing codes for VVT and for throttle valve potentiometer (even though the dealer had fitted a new genuine throttle body)

Thanks for your advice. I'm doing exactly that, logging all contacts and work done.
As for the dealer's liability like you mentioned, the car came whit a 3 months warranty, but what are exactly my rights during and potentially after the warranty finishes?

 

[Sidewaze Samm]

As for the dealer's liability like you mentioned, the car came whit a 3 months warranty, but what are exactly my rights during and potentially after the warranty finishes?

That's exactly what I asked Trading Standards. I suggest you have a chat with them. The warranty won't be worth the paper it's written on - unless there's some kind of seismic failure, and then don't count on it. We had the AA one, who wouldn't cover the work my indy (DLV) wanted to do. It's basically a sales aid for dealers.
I was told by TS that, theoretically, there is no time limit to a dealer's liability for faults to your car - within reason. It seems your dealer, like mine, was probably aware of a fault at point of sale. He gets two chances to fix it, then reject it. How did you pay - finance or credit card? Remember they are equally liable. We paid cash
Talk to Trading Standards, though calls are now fielded by CAB call centre, as they're very informative and supportive.

 

[kowsmou]

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[Sidewaze Samm]

On a positive not, it's never caused me a problem as such. More of an annoyance but hopefully it's finally going to be solved.

So long as the EML doesn't come on during the MOT...

 

[Z4Tuga]

Hi, I may be able to help here - also have a 2007 2.0 with the same issues, I'm a year down the line from you

First thing, the 'juddering'. Mine does the same thing so I just give it a bit more throttle the first couple of times I pull away from a junction. I've never bothered investigating it, it pulls away fine once the clutch / fluid has warmed up a little.

With regard to the engine light, this also came on shortly after I bought mine. The code you have is probably P0420 'catalytic efficiency bank 1'. I've been troubleshooting this for a while, the dealer I bought it from pretty much did the same thing as yours, plugged it in, reset the light and told me it was the fuel I was using (tesco). It went to a BMW specialist a couple of months later who put a new O2 sensor in it, didn't make a difference. Changing oil, filters & plugs made no difference either. To replace the cat on these cars you're looking at £1200 because they are integrated into the manifold and you can't buy after-market ones.

I made a breakthrough a couple of weeks ago and found a local indy that is somewhat of an expert on these engines, he's spent years taking them to bit and building them. Nothing obvious was showing when he plugged it in and he said the issue with these engines is that they are prone to pushing unburnt fuel through to the exhaust system which throws up the engine lights. You'll notice if you drive the car harder or on motorway journeys the light will stay off, this is because the cat cleans itself in the higher rev ranges and as it heats up. He said he's had plenty of customers who have had this same issue and replacing the cat only resolves it until it temporarily. He said a simple and cheap solution is to use something called 'engine restore' which prevents unburnt fuel from pushing through to the exhaust system. The cat cleans itself and stays that way - no more lights. I'm not a mechanic and I can't relay the technicalities to you but he said it works.

I was also worried my manifold was cracked but he said you would be able to hear it chuffing from the front and he was confident it wasn't that.

Lastly in terms of your rights. If you have a problem with a car you bought from a dealer within the first 6 months then the dealer must repair it. If the dealer is unable to repair it or it fails again then you are entitled to a full refund. It's that simple. There are further consumer rights which you can find online.

From personal experience, you're going to have to make a decision. The dealer is unlikely to be able to fit the engine light issue so if you want to keep the car you're going to have to own the problem. i would reccomend buy a basic OBD reader online (£5) so you can read & reset them yourself.

On a positive not, it's never caused me a problem as such. More of an annoyance but hopefully it's finally going to be solved.

Have you got any oil leaks ?

Thanks for taking the time to share your experience. It was definitely enlightening. I called the dealership today and they asked to keep the car one more day to test it again tomorrow morning. Like you said, sounds like a decision I will have to make. I will see how the car comes back from the dealership and how it behaves in the next few weeks/months and then make a more informed decision in case more faults appear. As you said, it doesn't impact on the car's performance, is just the annoyane of having the light there and have to keep resetting it. Just out of curiosity, what Petrol are you using now, and have you changed following the first time the light came on without results? Also, the potential solution you mentioned (engine restore) what is it exactly? Some kind of additive?
As far as I can tell, I have no oil leaks, but I haven't had the opportunity to have the car checked by my local independent yet, so can't say for sure!

As for the dealer's liability like you mentioned, the car came whit a 3 months warranty, but what are exactly my rights during and potentially after the warranty finishes?

That's exactly what I asked Trading Standards. I suggest you have a chat with them. The warranty won't be worth the paper it's written on - unless there's some kind of seismic failure, and then don't count on it. We had the AA one, who wouldn't cover the work my indy (DLV) wanted to do. It's basically a sales aid for dealers.
I was told by TS that, theoretically, there is no time limit to a dealer's liability for faults to your car - within reason. It seems your dealer, like mine, was probably aware of a fault at point of sale. He gets two chances to fix it, then reject it. How did you pay - finance or credit card? Remember they are equally liable. We paid cash
Talk to Trading Standards, though calls are now fielded by CAB call centre, as they're very informative and supportive.

Thanks for you guidance on this. It's something I might have to consider. Unfortunately I paid cash as well!

 

[Mike6]

There have been a number of posts on here about petrol quality issues. A general view seems to be that you shouldnt use supermarket petrol but a quality product from suppliers such as Shell or Esso who spend a fortune on fine tuning their products with cleaning additives etc. Some have reported running problems with supermarket fuel that disappears when you fill up with better fuel.
It probably wouldnt harm to add some redex next time.

 

[kowsmou]

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[cookie_190]

Hi Tuga and Kousmou,

I have just bought an 2007 Z4 2.0L and am having the exact same problem. 1st it was the emissions light, private dealer sent me to his indy who said the code was for the cat converter. So they replaced that. But light back on again within a few days. Code is again pointing to the exhaust system but the stats are all bang on where they should be.

Its also juddering in 1st when the engine is cold. I've written to the dealer to reject the car (waiting for response) but i'd prefer to have this problem go away if possible.

Think I'll give the engine restore thing a go, the juddering in 1st is really quite annoying, any more suggestions? Tuga did you get yours sorted?

 

[Z4Tuga]

I tried some more 'premium' petrols for a few fills but it didn't make a difference. Fuel isn't the cause of the problem I'm certain of that.

These cars are also prone to oil leaking from valve cover gasket and vacuum pump seals. You will notice oil on the left hand side of the engine in the little silver tray and on the bottom back of the engine block, respectively. Neither are expensive to fix really. The vacuum pump will also drip oil onto the exhaust and you'll smell it so that's also a sign it needs doing.

I don't know much about this 'engine restore' stuff. He said it's american and cuts emmisions significantly, amongst other things. I looked it up online earlier and it's £29 from eBay. I'll keep you posted as haven't actually tried it yet but he swears by it.

I'm starting to suspect that you are one of the previous owners of my car!
I've had the car inspected by an independent specialist today and I have the exact same oil leaks you described. I've read in the forum that they are quite common but it was still interesting as the mechanic was showing them to me, what you wrote kept coming back to my mind.
I'm now in the process of having these repairs agreed with the dealership.
The mechanic also noticed the juddering in 1st gear, so that`s definitely not me being newb with the clutch. He will investigate this further and I will report here any findings.
In the meantime the light has not come back, but I have done less than 100 miles since it was reset, so can't really tell. I will update the post if it does.

 

[cookie_190]

Good luck with it, yes please let me know the outcome of your juddering in 1st problem!

Cheers