OMP

Hi all.
Car is a 200 89 turbo aut…( MC-1)
Thing is the car runs "normal”, but here are the symptoms…
Car will take about 5 second cranking to start, althought sometimes it will fire up right away ( cold or hot)….but most of the times takes a bit of cranking…

Car will idle OK, but after the CSV stops actuating, idle will go under 800, but stable and no stalling. Then when it gets hot ( normal temperature ) after some driving, the idle will go over 1000 rpm….

Besides this, which I don't mind that much, in PARK, there is what sounds like a bad pinging noise around 2000-25000 rpm which will continue all the way up. When driving the car, it will launch about right, boost gets as it should to 1.3 around 3000 rpm's but then, when getting to 4000 rpm's the car doesn't seem to give all the power, it doesn't turn as smooth as it should and the turbo kick doesn't seem to arrive at any point…..although it keeps gaining speed, but with some effort on the pedal and slower than it should…

My mechanic says that it looks like a timing problem. He says timing doesn't advance, but doesn't know where to look at (he is not an Audi expert).

Talking with some people and reading about it around here, I figured that it could be :

Air temperature sensor : Does it really work as a timing data input??? Could it be???
Timing reference sensor : Could it be?? What would not work if this goes bad???
Knock sensor ???? Same….What would be like if this sensor didn't work???
Couple of these???
All of them????

What should I change first???
Can't pull codes, don't have time to build the led…

Many thanks……

**My first priority would be the air temp sensor…..How much is it????

boxerfan

Has anyone tried the fuel pump bypass mod? Sounds like you are having the same problem I just encountered.

The ECU will allow the car to idle alright, but once the WOT?idle switch opens from idle the fuel leans right out and there is very little power at all although the car will run.

The easy way to check? Swap ECUs. Get one from a wrecker for about $25.

OMP

Thanks boxer, but the thing is that I'm writting you from Spain, and there aren't many MC's around...nor automatics...
Will a 1B type (manual) ECU do???
If not, a good source to get it from the States by Internet??? Is it safe to buy without having the possibility to change it???
Anyother thoughs?? Thanks a lot

boxerfan

MAC-11B will work I think. Anyone second that?

audiqv8

In answer to some of your questions

Car will take about 5 second cranking to start, althought sometimes it will fire up right away ( cold or hot)….but most of the times takes a bit of cranking
When was the last time you gave it a tune up? Are you using the right spark plugs? What bar is your boost. Are you over boosting which will lead to pinging and fuel pump cutout?

Air temperature sensor : Does it really work as a timing data input???
No. It does impact the wastegate frequency valve duty cycle.

Timing reference sensor : Could it be??
NO. I don't think that it's your timing reference otherwise your car will not start. Yes this does work as a timing data sensor. It provide the ECU with information when number 1 cylinder is approaching TDC.

What would not work if this goes bad???
Engine doesn't start.

Knock sensor ???? Same….
Now the knock sensor does act as a timing sensor. If it detects that the engine is knocking then the ECU will retard the timing.

What would be like if this sensor didn't work???
You will eventually destroy your engine.

What should I change first???
Nothing

Can't pull codes, don't have time to build the led…
Spend the time to build the LED. Its taken me more time to type this than if you have gone to a electronic store and brought a 12v LED with resistor. Let your car tell you what's wrong with it.

Try going to a higher octane gas to see if it reduce the pinging. BTW the CSV is only on for a very short period of time depending on ambient temperature. Check your ISV and clean or replace it.

boxerfan

That's why it seems to me that the control for the fuel frequency valve isn't working.

I agree that the starting seems 'normal' for these old cars and I agree with the rest of your advice.

OMP

Higher octane gas?? I'm using 95....although I could go up to 98......should I?

audiqv8

Why not try a tank full and see if it helps. I always thought that it was difficult to get high octane gas in Europe, another urban legend? Maybe it just cost a whole lot of $$$$$.

My mechanic says that it looks like a timing problem. He says timing doesn't advance, but doesn't know where to look at (he is not an Audi expert). The timing is control through the ECU, there is no user intervention on a stock engine.

Have you check the hose between the intercooler and intake manifold aka Michelin Man hose??

Blink out the DTC codes and it will tell you more or take it into a shop with VAG-COM and have them tell you the codes.

OMP

I think I will. I'll put 98....Actually you can get 98 anywhere, put gas is expensive...
"Basic" 95 octane is 1,25$/Litre which means 4,95 per gallon....

98 octane is 5,30 $$$

ooouuuucchhhh!!!!! hopefully distances are shorter than in the States...