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MY01 - Over revving while driving

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Old 04 February 2002, 11:11 AM
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MATTeL
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Well a stuffed gear box is even worse thought! Although that certainly would be a warrenty job.

Thinking about (hence the edit) it isn't jumping out of gear as the car jumps about a 1,000 to 1,500 revs, then the revs settle down and the car carries on normally. It really is like dipping the clutch while driving.



[Edited by MATTeL - 4/2/2002 11:13:11 AM]
Old 04 February 2002, 11:23 AM
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ozzy
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Ok, someone with a bit more sense than me may correct me, but..

My understanding of a clutch is that it's not engaging until you put pressure on the clutch pedal. This forces the clutch plates together allowing you to change gear (without loosing several or all of the gear teeth).

So, if the clutch isn't engaged does that mean that a slipping clutch (i.e. the material on the plate(s) has worn away) wouldn't cause this problem?

Does it happen in any other gear? If it's just 4th, does this suggest that gear is stuffed?

Stefan

[Edited by ozzy - 4/2/2002 11:24:27 AM]
Old 02 April 2002, 09:38 AM
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MATTeL
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Question

While accelerating (hard) from 50mph in fourth the rev counter jumps rapidly, there is a corresponding increase in the engine sound and a surge from the car. The revs then return to normal.

It feels like I pressed the clutch pedal down while driving (I didn't). I am assuming this is a slipping clutch.

Could anyone confirm this for me and am I correct in assuming it is covered under the warrenty?

Cheers,
Mark
Old 02 April 2002, 10:07 AM
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ozzy
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Hmm, I always thought a slipping clutch would only show itself during gear changes when you're actually engaging the clutch plate and not during normal drive.

Could it be jumping into Neutral or some other gearing/drivetrain problem?

Stefan


Old 02 April 2002, 10:31 AM
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Dr Lurve
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Mark, you need to drive up a hill, if the clutch is slipping you will soon tell. Jen.
Old 02 April 2002, 11:04 AM
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UkLegacyT
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mattel,
exactly what mine did when it got chipped, clutch slip

fitted an AP one, and its fine now

ian
Old 02 April 2002, 11:21 AM
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elgordano
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Try pulling away in 2nd gear....you should be able.
You may get a better idea if it's clutch slip from this.
G.
Old 02 April 2002, 12:34 PM
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MATTeL
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Mine is PPP and has been fine since for the six months it has been fitted. The other mods; HKS Hiper and HKS SQV, have had no detremental effect on the other MY01's that have had them fitted.

I will try the uphill and second gear tests later, the only thing is I don't want to risk more potential damage as the dealer and I can only get together in a two weeks.
Old 02 April 2002, 01:30 PM
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Bitten Hero
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Arrow

The clutch operation is the exact opposite in fact!

By default, there's a very strong spring which holds the plates together. Pressing the clutch pedal pushes the plates apart, against the action of the spring.

When a clutch wears out, it means the friction plates have worn smooth (or are starting to do so) and so on high boost (i.e. midrange in 4th/5th) it may start to slip - i.e. engine speed is greater than the gearbox input shaft speed - which is exactly what you're seeing.

Definitely not a gearbox failure as once it had jumped out, it wouldn't jump back in again.

Clutch I'm afraid

Richard
Old 02 April 2002, 01:37 PM
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EvoRSX
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Definitely a slippy clutch.
It'll do it more if you're on the motorway in 4th and 5th and then give it a bootful of throttle. You will hear the engine noise and revs rise but you won't be going any faster.

Take care from now on until you get it sorted out as you may overheat the flywheel and warp it and need that replacing too

Andy
Old 02 April 2002, 02:55 PM
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MATTeL
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So at least this can't be blamed on mods and strengthen the case for the warrenty claim.

As you say it is only noticable in 4th and 5th when I apply heavy acceleration. Guess I won't being doing that for a while.

Thanks for the help.

Mark
Old 02 April 2002, 03:39 PM
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ozzy
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Cheers Richard for explaining it to a lay-person like me
Old 02 April 2002, 04:17 PM
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David Lock
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Sounds very much like clutch slip which will show up more in higher gears. Usual way to check/confirm is to start engine, engage handbrake hard, put in 3rd or 4th and gently lift clutch pedal. If engine revs and car stays motionless then clutch is slipping. Otherwise if clutch working properly you would probably stall her. DL
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