help~ 99 A6 1.8T engine start problem

[bjtupp]

Hello guys,

I am not a native english speaker, so i will try to explain my problem clearly.

I've got a 99 A6 1.8T with 106000 miles, automatic. From my previous experience, I noticed that people start their cars (especially automatic) by only switching keys to the ignition, then the engine will start. But this way does not work for mine all the time, sometimes I can only hear the start motor running and the engine wont start. Once this happens, the only way to start the engine is like this:
1. apply the brake twice or three times until the brake becomes "tight", what i mean is the distance that the brake can be pressed down becomes short.
2. keep applying the brake and insert the key, then switch it to ignition
3. when hear the start motor working, apply more pressure on the brake, once the distance becomes longer like normal, the engine will start.

afterwards, i can start the car by only switching the key to ignition, maybe after 2 or 3 times starts, the problem would show up again.

any ideas what might cause this problem? any help would be appreciated.

Nathan

[STEWY L]

nathan, i don't know the car at all but the only connection i can think of would be the brake
servo cylinder.
i think that this is connected through vacum hoses, to inlet manifold,and distributor/carb,if it has one.
can only think that in some way this is affecting the distributor timing advance/retard mechanism. i don't know exactly how the servo is constructed,but am sure it would have a
rubber diaphram ,or piston seals, which may have failed causing the distributor timing to
be too far advanced,or,if the servo is ok, the distributor timing mechanism is sticking and by pumping the brake pedal you are forcing it back to it's retarded start position.
what i have just said may be total nonesense,( i can hear everyone laughing), but as i said,
the only connection between the brake pedal and engine would be the servo/vacum hoses/
distributor.
hope you get it sorted in good time,and at least expence,
stewy.