Fault diagnosis needed please....

[Corsair7]

Got a developing issue with the motor, could do wth a diagnosis please....

Car is an Audi A4 1.9 tdi (thats not the problem!) with manual box.

If i'm in 5th gear at say 50mph, at about 2000rpm, and I accelerate, the revs will climb to say 2600 and then dump back down to 2200, before resuming the climb. Theres no difference with the acceleration, it still accelerates through 60, 70 mph. Its as if the car is an auto and its down shifting, but I'm not changing gears or even touching the clutch....

It does this at various revs in various gears, but most noticable in 5th.

I was guessing at first that the clutch was slipping, but it does this in gear, when I'm not using the clutch.

What is it that I'm going to have to find some money for....?

Cheers

[Adam_W]

Corsair7 said:

I was guessing at first that the clutch was slipping, but it does this in gear, when I'm not using the clutch.

Sounds aboout right, a clutch will slip when in gear if its shot

[mnkiboy]

Clutch. Virtually 100% it's the clutch.

Or perhaps it's icy out?

[ALawson]

I always thought a good test for a clutch was to try and pull away in 3rd, if it doesn't stall then the clutch is on the way out. Although it could be after trying this out!

[Wing Commander]

Corsair7 said:

Got a developing issue with the motor, could do wth a diagnosis please....

Car is an Audi A4 1.9 tdi (thats not the problem!) with manual box.

If i'm in 5th gear at say 50mph, at about 2000rpm, and I accelerate, the revs will climb to say 2600 and then dump back down to 2200, before resuming the climb. Theres no difference with the acceleration, it still accelerates through 60, 70 mph. Its as if the car is an auto and its down shifting, but I'm not changing gears or even touching the clutch....

It does this at various revs in various gears, but most noticable in 5th.

I was guessing at first that the clutch was slipping, but it does this in gear, when I'm not using the clutch.

What is it that I'm going to have to find some money for....?

Cheers

Your clutch is slipping. This happens when you are in gear, and the clutch plates are "hooked up". If the clutch is worn, the plates aren't held together with as much force, and so they slip when there is a high torque from the engine side. I presume that if you try to accelerate slower, it doesn't happen so much?

Solution is a new clutch. Cost depends on if you can do it yourself or not

[ChrisRS]

Another vote for the clutch slipping.

[MondeoMan1981]

ChrisRS said:

Another vote for the clutch slipping.

and another !

[naffa]

If your clutch is slipping then you're revs will rise considerably when accelerating but your acceleration will not match the rise in revs.
A bit like wheelspin but the slippage is not in the tyres but the friction material on the clutch plate.

[Corsair7]

Cheers guys, clutch it will be then. I had thought the clutch would slip only when engaging gear, didnt realise it was 'always' engaged as such.....

Guess its due a new clutch. Its the first one the car has had.....

milage is 263,500 btw....

[Corsair7]

Wing Commander said:

Your clutch is slipping. This happens when you are in gear, and the clutch plates are "hooked up". If the clutch is worn, the plates aren't held together with as much force, and so they slip when there is a high torque from the engine side. I presume that if you try to accelerate slower, it doesn't happen so much?

Solution is a new clutch. Cost depends on if you can do it yourself or not

Yeah, I tend to accelerate very gently mostly anyway (its my daily work grind car, and I do like to get 700 miles out of the tank on the commute...) so it could be I haven't noticed it so much because I've been so gentle with it the last year or so....

[lance1a]

Corsair7 said:

milage is 263,500 btw....

Errr.....yeah, clutch.

[carreauchompeur]

fk me, that's good going on an original part!

[davepoth]

carreauchompeur said:

fk me, that's good going on an original part!

Not a bad innings at all.