Judder on acceleration

SS-89

SS-89

SS-89

Soldato
Joined
13 May 2007
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London
Just noticed an issue today when accelerating whereby the car judders (not violently but noticeably). It felt like the turbos were struggling to spool but the effect is more pronounced in the higher gears (4th - 6th) which I'm inclined to believe is a sign of excessive clutch wear.

Any ideas before I send it to the garage? Also would the clutch be covered under my comprehensive bmw warranty? Car has 70k on the clock so I'm guessing not, I fear an expensive bill if it turns out to be the clutch.
 
What do you mean by judder? Does it feel like a transmission issue or engine? Turbo engines commonly develop boost problems which give inconsistent power. Can be things like a dirty maf, vacuum and boost leaks, problems with boost solenoids etc.
 
I had this exact symptom on my car a few months ago.

New coil packs (all 12 of them @ ~£50 each :eek:) solved it - it happens when the engine is at heavy torque loads, which is commonly low revs, high gear acceleration - in my car, above 2500 rpm it was fine. Felt like a new car when I got it back!

Just a recommendation, either don't drive the car or stay in lower gears to prevent this juddering from occurring, it is the engine misfiring which dumps unburnt fuel into the exhaust - this makes it's way into the catalytic converter and can ruin it.
 
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megakid said:
I had this exact symptom on my car a few months ago.

New coil packs (all 12 of them @ ~£50 each :eek:) solved it - it happens when the engine is at heavy torque loads, which is commonly low revs, high gear acceleration - in my car, above 2500 rpm it was fine. Felt like a new car when I got it back!

Just a recommendation, either don't drive the car or stay in lower gears to prevent this juddering from occurring, it is the engine misfiring which dumps unburnt fuel into the exhaust - this makes it's way into the catalytic converter and can ruin it.
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Do you also have a 335i? I think coil packs would be covered under warranty so that's reassuring and even if not a £600 bill is much easier to swallow than a potential clutch bill.
 
SS-89 said:
Do you also have a 335i? I think coil packs would be covered under warranty so that's reassuring and even if not a £600 bill is much easier to swallow than a potential clutch bill.
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Apologies, I should have mentioned that I don't have a 335i so the cost might be wildly different - I expect the bill for a 335i will be significantly lower to replace coil packs (only 6 coil packs required for a start).

The 335i almost certainly will record misfires (which cylinder etc) in it's ECU logs so a good specialist or a main dealer will be able to diagnose it pretty quickly I'd imagine.
 
SS-89 said:
http://www.bmwland.co.uk/forums/viewtopic.php?t=142796&p=1178141

This is pretty much exactly what I have (i.e more pronounced on heavy acceleration in higher gears) so it sounds like it could be the coil packs?
In all honesty it feels more like an engine issue but the only reason I thought it may be the clutch is due to the fact it was more pronounced in higher gears.
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The engine tends to be loaded more heavily in higher gears (lower RPM, higher throttle opening), which requires a higher voltage at the spark plug to create a spark, so these are the conditions under which marginal ignition systems break down.
 
megakid said:
Apologies, I should have mentioned that I don't have a 335i so the cost might be wildly different - I expect the bill for a 335i will be significantly lower to replace coil packs (only 6 coil packs required for a start).

The 335i almost certainly will record misfires (which cylinder etc) in it's ECU logs so a good specialist or a main dealer will be able to diagnose it pretty quickly I'd imagine.
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No problem, It's booked in to the main dealer near me on Thursday, I'm hoping for a quick diagnosis and repair as I need the car this weekend.

pepsilol said:
Checked the judder in the following scenarios ?

DSC Off

If auto:
Sport Mode
Manual Mode

Maf Unplugged
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Tries DSC off and no difference, I don't think it's a traction issue. Not sure about the maf, how would I do that?

Dogbreath said:
The engine tends to be loaded more heavily in higher gears (lower RPM, higher throttle opening), which requires a higher voltage at the spark plug to create a spark, so these are the conditions under which marginal ignition systems break down.
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Hmmm good to know, all signs are pointing towards coil packs so hopefully it's a relatively simple fix!
 
Why would it judder if the clutch is knackered?

I thought it was the other way round in that it would slip if the clutch was going.
 
SS-89 said:
No problem, It's booked in to the main dealer near me on Thursday, I'm hoping for a quick diagnosis and repair as I need the car this weekend.



Tries DSC off and no difference, I don't think it's a traction issue. Not sure about the maf, how would I do that?



Hmmm good to know, all signs are pointing towards coil packs so hopefully it's a relatively simple fix!
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Have you read the codes?

Unplug the MAF and go for a drive. Under bonnet, google it for a picture of its location. Usually next to the air filter.
 
pepsilol said:
Have you read the codes?

Unplug the MAF and go for a drive. Under bonnet, google it for a picture of its location. Usually next to the air filter.
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I don't have the necessary equipment (cables etc) to read the codes. Apparently the 335i has a map sensor and not a maf, I'm assuming it would still be located in a similar place? Will take a look when I get back from work.
 
SS-89 said:
Do you also have a 335i? I think coil packs would be covered under warranty so that's reassuring and even if not a £600 bill is much easier to swallow than a potential clutch bill.
Click to expand...


why a clutch and new DMF or solid flywheel would be less....


oh hang on its BMW it may not be ...lol
 
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