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Discussion Starter #1 (Edited)
Hello all,

The neverending work with my M5 Touring faces a new challenge after EDC-replacement, wheel refinish, audio installation, Inspektion II etc.

The car shakes violently while accelerating. First I thought I had the clutch warped, ordered a new clutch and tried to drive carefully until replacement. Now I noticed that this feeling of power being cut off and on occurs only when there is lateral acceleration to right side, meaning the car turning left (or with 1st gear also going straight).

This led me into conclusion that the clutch is not to blame for this. Or for that matter any other mechanical part in the drive train. I can still do doughnuts turning right, but there also the power comes on stronger when there is most acceleration to left side.

My guess is that the problem is somewhere in the ignition or fuel supply system. Has anybody here any ideas? Can some g-sensor cut power? Do I have some cable loose?

Rgds, Jussi
 

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Re: Stange drive problem

Just a thought?

Could be a probem the differential/half shafts, I know of Porsche 928s to sheer the bolts between the two. Only needs one of the bolts to have a bit of 'play' and with 340bhp hitting them they snap. This also leads me to think that the diff is OK as it is transferring power to one side as you pull a doughnut.

Don't think the sensors would show this fault. They would only default the EDC to the middle or soft setting plus giving you a (possibly) fault on your check control.




jussi_r said:
Hello all,

The neverending work with my M5 Touring faces a new challenge after EDC-replacement, wheel refinish, audio installation, Inspektion II etc.

The car shakes violently while accelerating. First I thought I had the clutch warped, ordered a new clutch and tried to drive carefully until replacement. Now I noticed that this feeling of power being cut off and on occurs only when there is lateral acceleration to right side, meaning the car turning left (or with 1st gear also going straight).

This led me into conclusion that the clutch is not to blame for this. Or for that matter any other mechanical part in the drive train. I can still do doughnuts turning right, but there also the power comes on stronger when there is most acceleration to left side.

My guess is that the problem is somewhere in the ignition or fuel supply system. Has anybody here any ideas? Can some g-sensor cut power? Do I have some cable loose?

Rgds, Jussi
 

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Discussion Starter #4
Cyrus said:
Prop dougnut?
I guess you mean that am I able to do a doughnut that looks like a propeller, or an 8. Have not tried yet.

Yewcorner, do you mean that by some bolt being loose, the car would behave as though it was cutting ignition? I was under the car today, and visibly checked the drive shafts. One of these days I will have to lift the car up and properly inspect the diff. Any pointers?

Jussi

P.S. Tomorrow to Germany for a couple of days and 1500km at nights.:noSMG:
(Un)fortunately with a rental E60 525i. Wonder will it do doughnuts?:hihi:
 

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I was looking more to the mechanical side as opposed to the electrical?

It's difficult to diagnose this fault but here is a few ideas:

Dirty/failed crankshaft sensor
Air leak on the intake side from the multitude of hose, valves, pumps etc, etc.
Faulty coil pack.
Faulty ignition lead/harness
Water in the spark plug recesses (Have you jet washed the engine?)
Throttle bodies need balancing
O2/Lambda probe failure
Engine bay earth strap loose/broken

I think you are going to have to go to your local BMW dealer and see if they can detect an electrical fault?

Let us know how you get on





jussi_r said:
I guess you mean that am I able to do a doughnut that looks like a propeller, or an 8. Have not tried yet.

Yewcorner, do you mean that by some bolt being loose, the car would behave as though it was cutting ignition? I was under the car today, and visibly checked the drive shafts. One of these days I will have to lift the car up and properly inspect the diff. Any pointers?

Jussi

P.S. Tomorrow to Germany for a couple of days and 1500km at nights.:noSMG:
(Un)fortunately with a rental E60 525i. Wonder will it do doughnuts?:hihi:
 

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Discussion Starter #6
yewcorner said:
I was looking more to the mechanical side as opposed to the electrical?

Let us know how you get on
Yes, I understood what you said. It was just my feeling, that the problem might not be in the mechanical parts, and turned out my feeling was to the right direction.

The problem was that when I had the Inspection II done, the guys in the workshop forgot to tighten the connection between airflow meter and the rubber boot going to intake manifold after changing the filter. When the car turned left heavily, banked the engine to right just enough to open a gap and mess up the airflow measurements accuracy.

By tightening this connection, I am now able to spin doughnuts both ways, and also use the car normally in other driving conditions.:M5thumbs:

Thanks for all good guesses!

Jussi
 

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Thank the Lord that was all it was; I should have mentioned the MAF to Plenum rubber bellow, these sometimes split, sorry.

Glad your up and running again though




jussi_r said:
Yes, I understood what you said. It was just my feeling, that the problem might not be in the mechanical parts, and turned out my feeling was to the right direction.

The problem was that when I had the Inspection II done, the guys in the workshop forgot to tighten the connection between airflow meter and the rubber boot going to intake manifold after changing the filter. When the car turned left heavily, banked the engine to right just enough to open a gap and mess up the airflow measurements accuracy.

By tightening this connection, I am now able to spin doughnuts both ways, and also use the car normally in other driving conditions.:M5thumbs:

Thanks for all good guesses!

Jussi
 
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