2001 A4 1.8t AWM - How to restore factory tune on ECU?

[mobildetroit]

My engine has been running rich forever, logging -25% Lambda.

I've gone through everything, vacuum and pressure leaks, timing, sensors, wiring, exhaust restrictions, fuel supply, ignition, etc...

I'm at a point where I'm starting to suspect the previous owner of this car put an inappropriate tune on the computer.
I have no way of verifying though.

Is there a way to just restore/upload the factory tune for my ECU?
I have Ross-Tech USB cable.....I hear there is software out there that one can use to upload tunes to the ECU.

Anyone out there know how this is/could be done? Any experience with flashing Audi A4 ECU's?

[Rodgman15]

You need maestro to reflash a stock ecu. Otherwise, pick up a stock ecu for cheap.

[mobildetroit]

Does anyone have any experience using this to flash an ECU on a 2001 Audi A4 or similar?
You can use it to upload and download the binary file of the ECU.
http://www.nefariousmotorsports.com/...shing_Software

I also came across this site, apparently it's a bunch of stock tunes for Audi computers.
http://www.chip-tuner.hu/original_ecu_files/files/Audi/

[walky_talky20]

In your case (where you are using a known stock tune to make a diagnosis), I probably wouldn't advise using your very first ECU flash to do it.

I'd advise either borrowing a stock ECU or picking up a used one. They are available for about $50.

[mobildetroit]

I agree, what is a good source for cheap stock unprogrammed ECU's? Ebay?....

How do I verify the computer I'm buying is unaltered?

- - - Updated - - -

...also, just found out my KII-USB Ross-Tech cable doesn't support flashing. grrrr...

[walky_talky20]

eBay or car-part.com.

For a 2001 1.8 Turbo, you'll want part number 4B0-906-018-M or 018-CH. (CH is for the 2001.5 with brake vacuum assist pump and sensor).

As for verifying they are unaltered...well, odds are they are not. Ideally you could buy one from a member here who could verify it was a known good, virgin ECU.

[mobildetroit]

Got one off ebay for about $70, same part number. Found instructions on how to re-calibrate it for my car equipment setup, which I should be able to do with VCDS.
I do need the CH model...so I'm good.
Seller said it's unaltered......so we will see. I should get it in a few days.
I think my ECU may have been damaged from shorts either on upstream O2 and/or CTS.
I discovered frayed wires on the O2 sensor last year and fixed...but the damage was likely already done.
Who knows how long the CTS wires were bare...likely longer then I've owned the car...and the car has always run kind of rich since I've owned it.
So, had some wiring issues at both of those sensors. Audi wires don't like high temps apparently.
I've also had to replace all my ignition wires because Audi used improper wire for the application (sitting on top of a hot engine).
I've replaced the O2 sensor so I'm good there.
The CTS connector I re-insulated with high temp silicone.
I also have a new CTS connector coming.
I'm going to verify there are no shorts between wires or to ground on those circuits back to the computer before I put the new computer in.
All the other sensor connections physically look good.

Also....if this is my issue the advice about borrowing a known good ECU may not be a wise test...for obvious reasons...lol.
Somebody should develop a tester to plug into the computer termination blocks to verify circuits

[walky_talky20]

That sounds like a good plan - fixing and checking all your suspect wires first before plugging in the new one.

Damage to a donor ECU is a possibility, yes. Best to be cautious.

Funny you mention an ECU harness tester. Audi does actually have a device for this. It is not automated, but it basically plugs right in place of the ECU and provides access to every pin so you can check them end to end. A breakout plug, if you will. It costs approximately 8 million dollars.

[mobildetroit]

Would anyone happen to know if the 2001 A4 avant has an O2 relay and if so where would it be on the relay block? i can't find a good diagram of the relay block for this car.

[Seerlah]

To find out if your EMC is tuned, log your requested boost. If your ECM is requesting more than 11psi (AWM), then it is tuned. That will determine if you have a stock or tuned ECM. As for running rich with the tune, a clogged cat converter can make you run rich. Just another thing to consider and look into. If original stock, they are very restrictive and could be your issue seeing that it is like two decades old.

As for "calibrating" the ECM, there is no real calibration. What is necessary is to make sure the soft coding matches your current ECM. The soft coding would include numbers that let the ECM know that it is being used on a manual, automatic, no seat belt chime, etc. When you hook up your cable to read the ECM using proper software, write down the soft code number onto a paper. Then if you need to swap the other ECM in, make sure the numbers match. If not, simply input the number code you wrote down on paper from your current ECM. This number should remain the same for the ECM to function properly on your car.

[Turbo_B5]

you can easily flash the ecu to stock with nefmoto and ebay cord. just need a stock tune from someone.

[mobildetroit]

To find out if your EMC is tuned, log your requested boost. If your ECM is requesting more than 11psi (AWM), then it is tuned. That will determine if you have a stock or tuned ECM. As for running rich with the tune, a clogged cat converter can make you run rich. Just another thing to consider and look into. If original stock, they are very restrictive and could be your issue seeing that it is like two decades old.

As for "calibrating" the ECM, there is no real calibration. What is necessary is to make sure the soft coding matches your current ECM. The soft coding would include numbers that let the ECM know that it is being used on a manual, automatic, no seat belt chime, etc. When you hook up your cable to read the ECM using proper software, write down the soft code number onto a paper. Then if you need to swap the other ECM in, make sure the numbers match. If not, simply input the number code you wrote down on paper from your current ECM. This number should remain the same for the ECM to function properly on your car.

I have disconnected the cat and run the engine to see if the -25% Lambda value would change and it did not.
I had an O2 sensor in the car that had exposed wires, one of which was the O2 heater wire. From what I understand the ECU supplies power to the heater.
The heater bit flip flops from on to off repeatedly regardless of driving condition or operating temp.
My conclusion is that the ECU may be bad from the short.
Got a new one coming and will see if it makes a difference on the O2 sensor.
I have a new O2 sensor in the car now.

[mobildetroit]

you can easily flash the ecu to stock with nefmoto and ebay cord. just need a stock tune from someone.

Agreed...and I've looked at nefmoto, I get it (I'm a computer scientist by trade).
The issue I have is that I have a Ross-Tech KII-USB cable and from what I understand it can't be used to do flashing.
I'll eventually give it a try...