S2 ABY Engine

[mathias]

Hello, ive got a problem with my audi s2, when it get up the engine temperature to normal it starts behaving strange, it dies on idle and when you drive, it kinds of cuts like it's loosing a signal or something for a short moment. The moment before the engine dies the engine control box clicks and when it has died it clicks again

It always starts also when it has died, when the engine is cold it runs like normal apart from the boost is always around 9 psi. Limp mode ?

I connected my vagcom and got 65535 - internal control module memory error on the engine.
I have opened the controlbox for the engine but didnt found anything out of the ordinary


The car has mtm chip,mapsensor. And 115R sparkcoils

Anybody got any idea of what it could be ?

[prj]

Pretty sure you have a certain "MTM" software downloaded from the internet that is missing a few bytes.

At least that is EXACTLY how that software behaves because some code is damaged.
The click is the ECU restarting due to the watchdog timer running out.

Send me the ECU, I'll fix it and put correct dwell settings for your coils

[mathias]

Pretty sure you have a certain "MTM" software downloaded from the internet that is missing a few bytes.

At least that is EXACTLY how that software behaves because some code is damaged.
The click is the ECU restarting due to the watchdog timer running out.

Send me the ECU, I'll fix it and put correct dwell settings for your coils

It has been running with the chip for about 3 years, the chip was bought at dahlback racing in sweden, but how can it just happen when the engine is hot ? feels stange if it just lost some bytes over the night

[prj]

It has been running with the chip for about 3 years, the chip was bought at dahlback racing in sweden, but how can it just happen when the engine is hot ? feels stange if it just lost some bytes over the night

If it was bought at dahlback, then it is probably the original chip.

As for losing bytes over night, depends what chip was used. Some people use non-automotive grade chips, and they are not rated below 0C.
So in winter when it gets cold, this can easily happen.

Make a pic of the chip on the top board... or better still, both boards.

[mathias]

If it was bought at dahlback, then it is probably the original chip.

As for losing bytes over night, depends what chip was used. Some people use non-automotive grade chips, and they are not rated below 0C.
So in winter when it gets cold, this can easily happen.

Make a pic of the chip on the top board... or better still, both boards.

ok, i will get a picture tomorrow, anything especially you want to see ?

[prj]

Numbers and labels off of the chips...

[mathias]

Numbers and labels off of the chips...

How much money are we talkin about if you fix the ECU ?

[prj]

Depends on what you want done with it...
If you are using 115R coils then the dwell time should be adjusted in the ECU, so that they last longer for example.

I could just send you two chips though, you can probably swap them yourself, if it has been socketed already.

What MAP sensor is fitted? 300kpa?

Money wise, I can say for now "less than 200 EUR".

[mathias]

Depends on what you want done with it...
If you are using 115R coils then the dwell time should be adjusted in the ECU, so that they last longer for example.

I could just send you two chips though, you can probably swap them yourself, if it has been socketed already.

What MAP sensor is fitted? 300kpa?

Money wise, I can say for now "less than 200 EUR".

Ok, no thats à problem that i dont have à socketed ECU , yes 300kpa

[prj]

So when it was chipped, new chips were directly soldered into the ECU?
You are sure they are not in sockets?

In that case, yes you will have to send it here.

[mathias]

Ive tried with an original ecu and the problem is still there, are going to change the multitempsensor and water temp sensor.

Any body got any idea of what it could be ?

[UrS4boy]

Ive tried with an original ecu and the problem is still there, are going to change the multitempsensor and water temp sensor. Anybody got any idea of what it could be ?

Well for starters, don't ignore prj's suggested possible causes. He knows more about the Motronic ECU than anyone I know of.

That said, if you just said that it died on idle (without the clicking), the normal answer would be clean your Idle Stabilization Valve (ISV) connection and the ISV itself. While this is not likely the only cause of your problem, to eliminate it as the cause, you should clean it. N71 ISV info (and info for the MFTS and G62 Temp switch) are available from the diagram linked below by clicking on the live labels in the diagram (N71 and G62 near the top, MFTS on the right side, etc):

http://members.shaw.ca/speedtek/UrS%20Engine%20Bay%20Device%20Map.html

[mathias]

Well for starters, don't ignore prj's suggested possible causes. He knows more about the Motronic ECU than anyone I know of.

That said, if you just said that it died on idle (without the clicking), the normal answer would be clean your Idle Stabilization Valve (ISV) connection and the ISV itself. While this is not likely the only cause of your problem, to eliminate it as the cause, you should clean it. N71 ISV info (and info for the MFTS and G62 Temp switch) are available from the diagram linked below by clicking on the live labels in the diagram (N71 and G62 near the top, MFTS on the right side, etc):

http://members.shaw.ca/speedtek/UrS%...ice%20Map.html

But i think that it could be something with the the temperature, becuse the boost is around 1 bar when its cold and when it turns hot its like 0.4bar. Im open to any idea of what it could, or ideas of what to test/check/clean

[prj]

1.0 bar is too little also if it's chipped.

Your course of action is as follows:
1. Pressurize the system, remove boost leaks.
2. Change the MFTS.

[UrS4boy]

The Multifunction Temperature Switch (MFTS) on the ABY and ADU is connected to pin 46 in the ECU T55 connector and is used by the ECU as a high temp alarm (> 119 C) - the ECU cuts off active boost control as a safety measure. If you MFTS has failed, your ABY ECU might assume high temps and is limiting boost once the engine has warmed up.

More MFTS info here:

http://forums.quattroworld.com/s4s6/msgs/22584.phtml