Funny Revs under Acceleration

[Wizza]

Yesterday night was driving down motorway and accelerated from around 70ish up with foot flat on pedal.

I heard the car rev funnily from around 2k to 4k and then to around 5k but all of a sudden the revs dropped back to about 3k and startes climbing normally again.

What can cause this proplem or can it just be a one-off? It didn't happen again last night and the car was at optimum temperature.

Cheers for advice

 

[Greeny233]

Sounds like the clutch slipping? Did the revs go up but the car didn't accelerate?

 

[Vex182]

I think it sounds like a slipping clutch, or a bad misfire.

 

[Wizza]

Well I know its boosting correctly but yes Greeny. Revs seemed to climb but at a much faster rate than speed than it does normally.

I'm sure Clutch isn't slipping as not had any problems before now and no problems today

 

[Wizza]

I don't think it's clutch as it only happens every so often if at all. Did it again today under acceleration (4th gear).

I have a feeling it may be fueling related.

Also just to point out when turning the car over it makes quite an odd noise as it there is a 'grinding' noise. Maybe starter motor lacking power?

 

[16Klappe]

Think about it.

The clutch is what allows a connection between the engine and the gearbox. If the engines revs rise and the car doesn't accelerate it can only be wheel spin or clutch slip.

Find yourself a wide open space, handbrake on tight with the engine running. Hold the revs at 3K and let the clutch out gently as though you were pulling away; if the clutch slips it's ****ed and get a new one. If it stalls then your wheels were spinning.

 

[Prawn]

perhaps someone has installed a badass ko4 hybrid that'll happily spin the wheels at motorway speeds like this?



If not, then your clutch is slipping....

 

[aragorn]

Yep clutch.

They fail in different ways, but "full throttle in 5th gear" is one of the ways to test a worn clutch, and yours has clearly failed.

In lower gears there is less load holding the engine back, so it revs up without slipping.

You can try Jardos test and see what happens, or find a nice long uphill stretch and repeat what you did on the motorway, ie 5th gear full throttle around 3k. It might well pass, but it'll only get worse from here. When mine failed, it would sometimes pull just fine, and sometimes it would slip. It seemed to vary from day to day, but the longer the trip the worse it seemed to get.

I very much doubt it was wheelspin, as even though prawns car is a monster, i very much doubt it would spin its wheels in 5th. Not only that, but in a standard car with an open diff, if it were wheel spin it'd have been pulling all over the road. Given you didnt notice anything other than the revs acting funny, i doubt it was wheelspin.

 

[Wizza]

No definitly not wheel spin.

I hope it's not clutch it's only 30,000miles old (if that) and it's single mass flywheel if that makes any difference.

Does anyone have any clue to the last part of my previous post.