Juddering when accelerating?

[metropolis986]

My 986 S has developed a juddering feel when accelerating, more noticeable on lower gears (and lower speeds).

I suspect that at ~89K it is the clutch as it has been quite heavy for a long time now.

Also, at a recent track day it developed, when driven hard that day, a very distinctive smell so it must be on its way out.

Am I correct to assume all this or is it something else? How much will it cost to fix independently (I already have an OPC quote of £1100 and am hoping to better that)?

 

[Motorhead]

It could be that the dual mass flywheel is also on its way out if you're getting a lot of vibration.

Get some advice and a quote for a clutch/DMF from a local Indy. It should be much cheaper than the PC.

Jeff

 

[Clewsey]

It could also be your Coil packs starting to fail if you are getting a juddering sensation at lowish speeds perhaps? Does it feel very sensitive on throttle on-off inputs at low speed. Does the car feel like it's kangarooing ? Three of mine started to fail recently and felt the same at low speeds.

Simon

 

[Clewsey]

BTW - a clutch replacement with a specialist should beat the quoted OPC price by quite a bit. I've had a rough cost from a specialist near to me who looks after my Boxster and it's more like £600 taking parts and labour into account.

Simon

 

[Glyn]

MAF symptoms

 

[spyderman]

89k on its first clutch? Time for a new clutch - and as mentioned, make certain the DMF is also checked.

 

[metropolis986]

Not sure if it is the first clutch or not (although I do suspect so), I've had the car for almost 3 years now.

I'll have the flywheel and coils looked at. The coils in particular I also think may need replacing anyway (they came up in a recent service but I have not had them done).

MAF; should this not come up as a warning light? I've had the air oil separator fixed very recently (two-three months ago).

 

[Giff]

Very easy to change the clutch, I had quite a bit of judder, DMF tested fine with box off and now smooth as silk with new Sachs kit installed.

 

[metropolis986]

Hi Giff, what did it cost you for the parts (for the clutch)?

 

[Giff]

Mine is a five speed 987 so the Sachs three piece kit was £237 delivered. I also bought the centring tool from VW for, I think, £15.

DMFs are a bit of a pain in the arse and you can only really test it with the box off. PelicanParts say they usually need changing every second clutch change.

I don't know what the score is with the 986 but the 987 has a system that makes you slip the clutch and as such the clutch can need changing from as little as 25k although more often closer to the 50k when I did mine.

If the 986 doesn't have this system then you may well still be on the original clutch.

 

[Glyn]

To test the MAF simply unplug it (the electrical connection) - then go for a drive, If it was the MAF creating the issue then the car will now run fine.

The car defaults to its limited operation strategy when the MAF is disconnected so it approximates the fuel/air mixture - which in terms of how a driver will feel it the fault will be rectified - the approximation is quite accurate - not accurate enough to pass an MOT but close enough to give what appears to be normal running. - If the fault remains at least you have excluded the MAF.

I don't know where the theory of the clutch is coming from - unless you mean juddering when engaging the clutch when pulling away but your description was whilst accelerating so I assume your foot is off the clutch completely - hard acceleration will produce clutch slip and the revs will rise whilst the speed doesn't - but it couldn't judder unless the clutch grips then slips - and if it did this then the clutch would be well and truly shot and you would have massive and constant clutch slip in all gears and all revs.

 

[metropolis986]

Yes, I really don't know what this is. When the engine is cold it is more noticeable I've realised; once it warms up it's much better. Maybe I am just getting used to the clutch/car behaving like this?

I am starting to suspect something else is wrong; the engine light has now come on out of the blue whilst the car was running. Nothing seemingly wrong and could be unrelated of course...

 

[Clewsey]

To me it still sounds like some of your coil packs are failing.... Is your car really jerky when cold coming off a very light throttle? I'd advise getting them looked at.

Simon

 

[Clewsey]

And forgot to say the Engine light will come on if they fail. It didn't for me but then the coil packs hadn't failed completely.

Forgot to ask - does the car feel like it's under-performing more than usual? Mine felt more sluggish, running more rich etc. Much better once the 3 c/packs were replaced and the jerkiness dissapeared altogether.

Simon

 

[Motorhead]

You really need to ascertain whether the problem is mechanically or electrically-induced.

Just to reiterate the points which have been made: if you're getting juddering on take-off, it's likely that the problem is clutch and/or DMF-induced but if the problem is more apparent when you're under way and is more a case of a rough-running engine due to faulty fuelling or ignition, then it's more likely to be an electronic issue. The fact that now you're getting a CEL tends to indicate the latter and many of the engine-related problems posted here are due to faulty coil-packs and MAF sensors.

If you don't want to get into swapping components, the best thing is to get along to a local Porsche Indy for a diagnostic check which should isolate any electronically-related issue(s).

Good luck and keep us posted.

Jeff

 

[metropolis986]

I have a feeling it's a combination; the coils were inspected by the OPC and they've already told me they're cracked.

Btw what is the cost of replacing those?

 

[Clewsey]

I got 3 Porsche OE coilpacks for about £105 inc. VAT, didn't need to replace all 6.

If they are cracked that will be the issue and you'll soon see the improvement with them replaced!

Simon