Lingering Revs

[Bigfatbob]

Does anyone know why the revs on my cars "linger" when I accelerate. If accelerate quite hard to say 5-6k, the engine takes a long time to slow down making the gear change slow, otherwise it is very jerky.

What can I do to fix this?

Cheers
Will

[DaveP]

You can fit a lightweight flywheel...this should help...but there can be drawbacks depending on which type you fit (such as a slight rattle at low revs under load)

[derdle]

Could this be a sign of an air leak ??? I know mine did this once and it had an air leak - a split hose which when replaced restored the rev behaviour to normal.

[Bigfatbob]

Was this discovered by a garage or youself and how did you identify the hose that was faulty?

[derdle]

It was discovered by Kim at QST doing a pressure test.

[Bigfatbob]

Could this be a sign of an air leak ??? I know mine did this once and it had an air leak - a split hose which when replaced restored the rev behaviour to normal.

Just a further question then. What is "normal" behaviour? should the revs rise and fall quickly or is there a certain amount of "lingering" as that is the nature of the engine.

[derdle]

Now you ask I can't quite put my finger on it...all I know is the car behaved (as I would call) normally after the split hose was replaced! I think I first noticed a problem when gear changes were not as nice as they used to be.

[simple1]

The idle speed is controlled by a valve, same one that controls idle speed when air con or lights are switched on........... the valve does have a habit of gettin blocked with burnt oil deposits, it could also be the result of an incorrectly set throttle switch........... not much help I know.......

[Golich]

The RS4 should not do what your describing.

But if you were talking about a new style 1.6 A3 they are shocking. I swear they have set the ECU to increase the revs on pressing the clutch. This was ceratinly the case with the loaner I had over a year ago!

[Bigfatbob]

Could the problem be ECU related? Is there much difference in revs "drop" between a standard and modified RS4?
A trip to AMD or QST might be on the cards to discuss options.

[Golich]

Very unlikely its the ECU. No tuner would introduce this kind off response. Its more likely an air leak somewhere. That kind of problem can occur in any car.

[911TT_STEVO]

This is why I recently made a post regarding my Porker having a boost leak!

I don't want to make you guys paranoid but it is always worth getting it checked, I was always 0.5 bar and when I had the ECU done it should have been double (still was 0.5) that's when I knew something was wrong! I have a meter in the car, so this gives me some indication. But if you have a boost leak you will lose a bit of power and also fuel consumption!

[Bigfatbob]

How do you identify where the leak is? And are there particular areas I should be looking?
The garage will be doing this but if I can point them in the right direction it might be quicker and cheaper.

[simple1]

This is why I recently made a post regarding my Porker having a boost leak!

bit of power and also fuel consumption!

At 80 miles to a tank round Spa, maybe I have a boost leak

[911TT_STEVO]

This is why I recently made a post regarding my Porker having a boost leak!

bit of power and also fuel consumption!

At 80 miles to a tank round Spa, maybe I have a boost leak

might well have after your foot wasn't lifted once!