I serviced my 1999 1.3 Mpi - Oil, filter, plugs. I then cleaned the throttle body by removing the air intake cowling and spraying carb cleaner in to the throttle body at a high tick over - think in total I gave five short blasts of cleaner over a five minute period.

What I have noticed since is tha the Revs pick up fine but drop significantly slower than they used to..... example would be changing down form fourth to third, (slow downchange) revs would pause for a second poss second and a half with clutch dipped and foot off throttle before dropping. This is also the same when stationary with reves held (by throtle) at 2000 rpm then foot off revs pause then drop. it is not a set rev specific issue it is slow to drop form any revs. Car idles fine.

it is certainly not a peppy as it was prior to the service where throttle reponse and engine repsonse was spot on.

Any ideas???

Cheers

Michael

Edited 29 November, 201015 yr by Big man

Depending on how mucky the throttle body was beforehand, it may well need resetting - either by running an alignment procedure with VCDS/VAG-com or just disconnect the battery for 24 hours to clear the learned values in the ECU. Otherwise an air leak in the exhaust manifold/downpipe (before the lambda sensor) can also cause similar symptoms due to overfuelling in the idle position.

I'm not sure how likely it is but it may also be worth cleaning the MAP sensor just in case anything shifted from the throttle body ended up in there.

carb cleaner "may" kill the lambda probe too just to cheer you up like.. :wonder:

carb cleaner "may" kill the lambda probe too just to cheer you up like.. :wonder:

Ah Bugger....but would that account for the slow re drop as above?

Just pased its MOT about a week after the carb cleaner was used so no issues re emissions there.

Depending on how mucky the throttle body was beforehand, it may well need resetting - either by running an alignment procedure with VCDS/VAG-com or just disconnect the battery for 24 hours to clear the learned values in the ECU. Otherwise an air leak in the exhaust manifold/downpipe (before the lambda sensor) can also cause similar symptoms due to overfuelling in the idle position.

I'm not sure how likely it is but it may also be worth cleaning the MAP sensor just in case anything shifted from the throttle body ended up in there.

Will Check for an Air leak etc on the downpipe and manifold, although car passed its MOT two weeks ago with no issues and fault re Reves after carb cleaner was used.

Also will disconecting the battery cause any other problems or just clear the values?

Where is the MAP sensor please

Many thanks

BM

If disconnecting the battery causes any problems at all, then you've got other faults that need seeing to! I had both the battery and ECU, among other parts, removed for at least 24 hours and the only effect was that the car ran better when put back together.

On the 1.3, the MAP sensor is in the middle of the inlet manifold, kind of behind and under the throttle body - just unplug the 4-pin connector and remove the 2 (probably torx) screws to pull it out. When I cleaned mine I gave it a quick squirt or two of carb cleaner down the tube and a shake to get anything out again - I can't guarantee that this is a good idea but it doesn't seem to have harmed mine. I wouldn't poke any implements down the tube, though, as you could potentially damage the pressure sensor that way.

If disconnecting the battery causes any problems at all, then you've got other faults that need seeing to! I had both the battery and ECU, among other parts, removed for at least 24 hours and the only effect was that the car ran better when put back together.

On the 1.3, the MAP sensor is in the middle of the inlet manifold, kind of behind and under the throttle body - just unplug the 4-pin connector and remove the 2 (probably torx) screws to pull it out. When I cleaned mine I gave it a quick squirt or two of carb cleaner down the tube and a shake to get anything out again - I can't guarantee that this is a good idea but it doesn't seem to have harmed mine. I wouldn't poke any implements down the tube, though, as you could potentially damage the pressure sensor that way.

Excellent...im off work form tomorrow for a few days and will give it a go and post how I get on.

Cheers

BM