Lumpy Running

[Anonymous]

Hi…..

I’m new to the forum and wanted to run an issue past you that I’m having with my (2006) Z4 2.5si – E85.

The problem has been on going now for eight months and I am now approaching the end of my warranty with no fix in sight. The car will run perfectly in-between the engine management light coming on and the car running lumpy but each of the below fixes only last 6-8 weeks of use (car is only used at weekend due to work). Petrol wise I only use 98+ RON with the odd occasion using 95.

The issue usually starts upon stat-up although has occurred while driving, when the engine is started up it will fire but the engine will struggle for any power and performance, with the revs at idle ranging from 500-1200 before cutting out. While driving the revs will naturally drop when slowing down and then engine will cut out altogether. On occasion I have been able to correct the issue by re-starting the car a few times and it will fire up correctly.

So far the issues have been so far:

Engine management light came on after lumpy running and eventually cutting out – Garages answer, re-set the fault light
Engine management light came on after lumpy running and eventually cutting out - Garages answer, build up in the throttle body
Engine management light came on after lumpy running and eventually cutting out - Garages answer, replace the ignition coil on the fourth cylinder
Engine management light came on after lumpy running and eventually cutting out - Garages answer, timing issue currently being investigated

Has anyone has a similar problem?

 

[mac27040]

garage should be able to tell you what fault code it throws up, poor running can be many things a fault air flow meter would give similar symptoms.

 

[mr wilks]

could be all manner of things . coils,plugs,leads,MAF, battery power etc etc . the fault code is only a guide & not necessarily gives you the solution .
a change of garage would be my next move .
you don,t say where you are but maybe a decent indy could be recommended ?
welcome aboard BTW & in 8 months you should have a good few pics for us to peruse :roll:

 

[Anonymous]

Thanks for the advice.....the garage should get back to me in the next day or so, I'll keep you posted.

It's currently at its second garage, the first one (BMW Kings Lynn) was the one that just suggested re-setting the code.

 

[Hepperz]

Hi

I'm having exactly the same issue by the sounds of it.

We've had the AA out several times, and each time I think they've cleared out the throttle body saying that was causing the problem - along with it having been used for short journeys.

Since then, we've only used it for longer trips so that it gets properly warm - but we've had the issue re-occur again.

Did you get any answers from the other garage?

Thanks

 

[bcworkz]

Hi Hepperz, welcome to the forum.

Do you also have the valvetronic type engine (N52) introduced on Zeds in 2006? If so, the throttle body is just a backup device and unlikely to cause rough running. The valvetronic mechanism throttles the engine by varying the valve lift in the head. The part most susceptible to build up is the MAF sensor.

If you have the earlier M54 engine, the idle control valve is also susceptible to build up issues, it runs parallel to the throttle body. This engine will also have MAF issues.

Problems with coil packs are also common with both engines. Good luck with getting your car running well.

 

[th30d0r3]

Sounds like Vanos Sensors are clogged up; I was having similar issues until I took them out and cleaned them now the problem has completely gone.
Once cleaned you can either let the car sort itself out after a few days of driving or force it by resetting it using software which makes it "re-learn" itself.
I opted for the former since the latter would entail me walking back into the house to get the laptop.

 

[MrPT]

Experienced something similar as well.

http://www.z4-forum.com/forum/viewtopic.php?t=45778

Also suspected Vanos but it's fine at the moment.

~ Now Tapatalking in HD ~

 

[andysat]

Hi and welcome!

 

[Anonymous]

Hi,

Here's an update from my post a few months ago, it’s been a while but I’ve spent more time in the garage than on my laptop....

Main dealer has investigated the lumpy running on three separate occasions and has put it down to the timing each time, as a result the vanos unit, timing chain tensioner have been replaced and the ECU has received an update.

All was going well until last week when the ECU light came on for no obvious reason, as the car was running fine. So I took it back to the main dealer where they advised it was timing related but couldn't understand what was the cause of it. So BMW technical were called in and their diagnosis was that swarf is causing the issue.

Down side to all this is that the main dealer wants to take apart the block to find the cause of this issue at a cost of £3,000 and that’s just to investigate.

So this is fast becoming a nightmare, I don’t know if regular oil changes will keep the car going in the short term.