Judder

[Suffolk944]

Last couple of Sundays when I have gone for a spin to blow the cobwebs out of both car and driver I have noticed that under strong acceleration there is a what I can only describe as a brief judder or stutter from the engine which then clears.

This only seems to happen until a few miles have been driven and things are warming up. As the weather has been so soggy of late and my garage is far from perfectly leak proof am wondering if this phenomena is caused by damp affecting something - She is only getting the occasional weekend use at present.

If it is damp what is the likley area - plugs ? distributor cap ? What should I do to rectify this ?(other than hope for dryer weather !)

Or might it be the portent of some other fault that may prove *gulp* more expensive ?

As ever any advice most welcome. []

 

[Suffolk944]

/bump

Just in case anyone has any ideas []

 

[Diver944]

Sorry Jonathon, no ideas from me [&:]

All I can do is be really condescending and say that I would not advise using strong acceleration until your car is fully warmed up anyway. Mine seems to take at least 5 minutes or 5 miles to get fully warm and I'd never use boost until after that point.

 

[Suffolk944]

Yes just to clarify this isnt booting it straight out of the garage but after a few miles and a good number of minutes, even then not giving it the full beans by any means - It is a new phenomena hasn't happened until last few weeks in the 3 and a half years I have owned her.

It certainly clears after few more miles which makes me think its dampness somehow though suppose it could well be some other gremlin lurking.

Will just have to keep an eye on the situation I guess [&:]

 

[sawood12]

Sounds like it's temperature related if it happens when the car is cold then reduces/dissapears when the car warms up - as if something is coming upto temperaure, expanding and taking up any slack or play. Just to clarify - does the judder come through the steering wheel? A classic is the steering U/J shaft wearing. When cold the worn U/J's have play in them therefore you get a judder through the steering wheel - just like out of balance wheels, then as the shaft warms up, as it runs paralell to the exhaust manifold, it expands, lengthens and takes up the play in the U/J's and the judder subsides. Replacement of the steering U/J shaft will cure the issue.

 

[Fen]

ORIGINAL: Diver944
Mine seems to take at least 5 minutes or 5 miles to get fully warm and I'd never use boost until after that point.

Much longer. If you had an oil temp gauge you'd be amazed how long an engine takes to get warm. Coolant temp is almost meaningless. I'd say at least 15 miles of dual carriageway driving with revs up to 3,000 or so to be safe, less distance but longer time in town where you're moving slowly.

 

[Suffolk944]

Am trying to think of a better word than judder - its a drop off in power or hesitation/miss-fire from the engine when on boost which lasts a second or two then its gone and full power returns. After few miles its gone - electrical or plugs ?

More I think of it the more am wondering if its turbo related ? Cars done 120,000 miles so might turbo wear be a possible culprit ? Fraid I dont have a huge amount of mechanical knowledge to fall back on.

 

[sawood12]

The turbo should easily be good for 120k miles unless it's ingested some foreign object that has caused damage.

 

[Guest]

ORIGINAL: Fen

ORIGINAL: Diver944
Mine seems to take at least 5 minutes or 5 miles to get fully warm and I'd never use boost until after that point.

Much longer. If you had an oil temp gauge you'd be amazed how long an engine takes to get warm. Coolant temp is almost meaningless. I'd say at least 15 miles of dual carriageway driving with revs up to 3,000 or so to be safe, less distance but longer time in town where you're moving slowly.

I found watching my oil temp gauge that it took about twice as long to reach operating temp as the coolant did.

 

[eastendr]

You should get the oil up to above 80 deg C before the engine's ready for serious stress.

 

[zcacogp]

Back to the original question ... I'd suspect something electrical. When were the plugs last changed? When was it last given a full service?

New plugs, check the inside of the dizzy cap and rotor arm. If the plugs cure it, good. If the cap is manky, clean and/or (better) replace. And the rotor arm as well. If this doesn't cure it, try borrowing some new HT leads to see whether this makes a difference.

I'd have thought that by the time you get to putting new leads in, you will have cured it.


Oli.

 

[Suffolk944]

She had a full service about 8 months ago - Was thinking about the dizzy cap etc as have no idea when they were changed - will take a look at the weekend.

 

[rob.kellock]

when I had a similar problem, advice from this forum was to change the fuel filter; worked for me[]

 

[Jonny B]

Yeah ive had simerler symptoms and i put that down to fuel, poor.
Anyone had problems with shell 98 octane? it randomly makes my top end tappety so had to stop using it

 

[Fen]

I can't think why 98RON would affect the top end noise, probably coincidental and caused by something else I'd have thought.

I had a crimped fuel line once after a filter change, but that caused poor running after a while, not right away.

 

[944Turbo]

Where is your air filter?
Mine is a cone type behind the headlight and if the car has been standing in the rain, first few times I really get into the boost I have a hesitation - pretty sure water is dripping off the bonnet into the airfilter which then takes a little while to clear through.
Tony

 

[Suffolk944]

Mines a cone filter in same place - while she is garaged its not the most water tight of garages so maybe this is another possible cause. That said its been the same for much of teh last three years and its only just started being a problem.

 

[Diver944]

I have to admit that I'm a bit concerned about having an open cone filter there when my Vitesse Racing Maf arrives as my Turbo lives outside too and the slope of the bonnet and panel gap means that rain water could roll straight in there [] I think some sort of lid will be in order. I have the Lindsey Maf Trap to fit around and block engine heat so I'm sure some sort of lid will be in order.

 

[944Turbo]

To be honest now I know what causes it it doesnt really bother me, however I have been planning a very small duct that would cover the area and bring in nice cold air. I think some ali sheet attached to leading edge of the bonnet (the slopey undeneath edge) and extending over the gap will stop rain and duct in air without creating too much drag or lift on the bonnet and be fairly discreet.
Tony

 

[Hilux]

I'm a bit concerned about having an open cone filter there when my Vitesse Racing Maf arrives as my Turbo lives outside too and the slope of the bonnet and panel gap means that rain water could roll straight in there

Wrap it in cling film? [8|][8|][8|][8|][8|][8|]






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