E46 M3 - jerky/hesitation when accelerating

[Sankekur]

Just spoke to the dealer, says they have found the problem. They reckon the alternator was not giving the battery sufficient juice to charge the battery. This lack of electricity causes jerky drive and produces loads of fault codes.

Does this sound right?

Getting her back tomorrow do will report back then....

Hmmm, that doesn't sound right.

 

[The K-Man]

I'd like to get the final on this thread too. My sentiment is that the AFM will give a more constant problem when it starts going.

 

[M3west]

Hi,

Got the car back this morning. Audio issue was sorted, replaced head.

But......the car still feels jerky. I have never driven anther M3 so maybe it is normal. It pulls but kind of feels jerky, pulls like a train but when pushing from 2000 up she feels like the throttle is not linear. Not sure how best to describe it......just would have thought the acceleration should be vast....but smooth.

Other M3 guys.....do you have the same issues and is this maybe normal?

Just spoke to the dealer, says they have found the problem. They reckon the alternator was not giving the battery sufficient juice to charge the battery. This lack of electricity causes jerky drive and produces loads of fault codes.

Does this sound right?

Getting her back tomorrow do will report back then....

Hmmm, that doesn't sound right.

 

[calypso]

Really sounds like throttle position sensor.

 

[akash]

Maybe a faulty spark plug or coil pack.

Just my guess.

I say leave the car at the dealers until they sort it put

 

[Sankekur]

Really sounds like throttle position sensor.

From my experience that usually throws a error light on the dash (the EML one or the engine one, can't remember which) and the car goes into a sort of limp mode.

 

[Gizmo]

IT IS THE THROTTLE ACTUATOR!!!!:nonono:

 

[M3west]

Morning,

So I went back to the dealer this week as the problem was worse than ever. The workshop manager has now agreed the problem is the MAF so she goes in on Monday to have it swapped out.

Expensive part me thinks

 

[calypso]

Que Gizmo

What codes is it throwing?

 

[Clownshoe]

Mine did this for a while and progressively got worse. It starred of as a slight hesitation and ended up with a very jerky drive to the dealer. Faulty coils...

 

[M3west]

Que Gizmo

What codes is it throwing?

No codes as of yet. Last time it was in the codes pointed to low voltage. They swapped out the alternator, I noticed zero difference. Now a month or so on she is very jerky and feels kak to drive. Let's hope it's the maf. Next will be coils and throttle position sensor.

Let them replace as much as they want

 

[M3west]

Hi Guys,

So an update guys.

The car went back and BM replaced the alternator again!!!!! they reckon the low voltage codes had thrown things out causing the entire systems to be out of sorts. So a new alternator and battery no change. Driving even worse than ever. So on Friday it was driving so badly that I pulled in and got a mechanic to drive with me...for once it was doing it with someone from BMW in the car. Again they suggest the MAF, back to workshop...quick diagnostic and it's the MAF. One on order so hope to get it installed this week.

I'm super excited as mine is the only M3 I have ever driven and i'm positive it's never been right since I bought it.....so should be a huge difference !

Will keep you guys updated as the saga of the bouncy M3 continues

 

[calypso]

I thought they did the maf already? Im gonna need a new one, or mines gonna need a clean. Codes say my car is running abit rich.

 

[M3west]

I thought they did the maf already? Im gonna need a new one, or mines gonna need a clean. Codes say my car is running abit rich.

No, they said after the first alternator it might be the MAF. Went back in and they found the first alternator to be faulty....swapped that....not the problem. So now MAF is back on the radar

:thumbs:

I imagine they are expensive????

 

[kabal]

have you tried driving with the maf unplugged?

 

[M3west]

have you tried driving with the maf unplugged?

No, I have not. Is it easy to unplug to test?

Will it have any negatives by doing this for a short test?

 

[kabal]

yah, just open the bonnet and unplug.

car might run a bit rich and consumption will go up, but it should let you know with pretty much certainty if it is your maf or not

 

[M3west]

Update:

Got her back today, MAF changed and throttle position sensor changed. All settings cleared so will need to drive a bit tomorrow and see if the problem has entirely gone.

Brief drive home in the rain it felt MUCH better. I noticed that the jerking at low speeds has gone but also gear shifts are MUCH smoother (even on gear change speed 4)

Will report when it stops pissing down in Cape Town !!!:nonono:

Must just add....my dealer is doing a great job putting up with me...props to them !

 

[M3west]

OK, update time.

So the really bad hopping around town is gone. But sadly I was cruising at 110-120 today and I felt the hesitation again. I can only describe the feeling as the entire drive train jerks backwards and forwards. I think it is not as bad as before but I felt it several times over the drive to town.

I also still think the acceleration from 2/3k RPM is not nearly as linear as it should be. It just feels delayed and jerky.

PLEASE some one help me before I go mad....she goes out of motor plan next month. I know it's pre existing but would like to get to the bottom before it expires.

So alternator replaced twice, MAF replaced and throttle position sensor replaced.

What's next?

 

[calypso]

gizmo brought up the throttle actuator a few times.