My last free service by Audi Turbo help

[orsum]

I am about to have my last FREE service done by Audi on my 1996 S2

I have two issues I am concerned with. One being the engine has cut out 3 times for about 1/4 of a second over the last 100km. This happened when at idle but the engine did not stop is sort of missed a heartbeat. At the same time this happened the rev counter etc dropped to zero and then came back to idle.

Any ideas what it could be?

As I said having only done about 100km in the car since I bought it and not being familiar with the performance and characteristics of the turbo I am concerned that the turbo is not functioning as is should be. I do not think it is boosting correctly but I could be wrong.

In my A4 2.0T I can feel the turbo coming in.

Please note in South Africa Audi do not have to my knowledge anybody who if familiar with the S2 so I will basically have to guide them.

Can anybody advise what could be wrong and how to ensure they test the car correctly.

orsum

[Nero]

You should feel the turbo kicking in, there are some thing that can cause low boost.
Check your wastegate valve (N75) and multitempsensor near your inlet manifold. I would replace them both when the condition is unknown.

[orsum]

If the Audi tech connects a boost gauge to the engine were should it be connected and

(what boost at what revs should I get, found this info on S2 Central)

The car is presently standard no modifications have been made.

orsum

[VagOrBust]

One being the engine has cut out 3 times for about 1/4 of a second over the last 100km. This happened when at idle but the engine did not stop is sort of missed a heartbeat. At the same time this happened the rev counter etc dropped to zero and then came back to idle.

Two: As I said having only done about 100km in the car since I bought it and not being familiar with the performance and characteristics of the turbo I am concerned that the turbo is not functioning as is should be. I do not think it is boosting correctly but I could be wrong.

I'm with Nero on two. Most probably a boost leak and there's a lot of info on here how to tackle those.

As for one, probably the ISV (Idle Stabilisation Valve) is clogged with old oil. On my S6 it's here:


You can clean it using brake cleaner:
- First rinse untill no more crap comes out.
- Then leave partially filled so that the remaining crap can desolve. (Put it in a vise and forget it for half a day.)
- Rinse again to get the last crap out.

And lastly wash away all the brake cleaner with some WD40 or the like to prevent the seals in the valve from drying out. Blow clean with air and put it back into your car.

I think the boost should be a 1,7 to 1,8 bar absolute (so +0,7 bar boost) unless you floor it at low revs in 5th / 6th gear at which point the overboost should kick in for a temporary 2,1-2,2 bar (+1,2 bar boost) in the 3000 rpm range.

By the way, once you get these little problems sorted out: Get a chip in your car. You'll love the difference it'll make.

[orsum]

Thanks

orsum