Ecu swap disaster (RIP MY A4)

[smirnoffandcoke]

I recently bought and installed a tuned ecu for the same car as mine but with a slightly different model number.
ORIGINAL: 8e0909518b
New: 8e0909518ak

I removed the injectors, intake manifold and a lot of other stuff in that area to clean and put back. Once the new ecu was in and everything was bolted back together the car was not running well...

It has a bad missfire and engine warning light. You can drive it, but only just.
Sooo I put the old ecu back and the problem persists! 😭 It runs like sheeit still!
Recently the brake lights have come on with the ignition and there is another abs warning light flashing. The stock ecu is playing up!

My car is an 02 a4 B6 1.8tq and is completely stock exc for a test pipe.

I scanned for DTC with my VCDS cable and VCDS lite and it came up with 7 different engine fault codes including Multiple missfire detection. I am now unable to drive to work and am desperately needing help :( before I pay millions for the dealership to look at it, what can I do?

[walky_talky20]

I'm not understanding what the scope of work was, exactly. Why was the intake manifold removed for an ECU upgrade?

Did you remove the valve cover as well?

Please post all 7 codes with the code number and description.

[rocket1420]

Given the information, we can only make wild guesses. And my wild guess is you messed up the injectors. Like walky said, we need the codes to at least get some direction. Misfires can be caused by dozens of things.

[CyberPMG]

Was the tuned ECU from the same year as yours? You have a 2002 A4. If it's anything like the 2002 models sold here in the US, those ECU will only work with other 2002 models. When swapping ECUs, make sure you get one from the same year to best ensure compatibility. Even then, you need to be careful about different immobilizers between the ECUs (unless it's been coded out with the tune).

If the only thing that changed is the ECU, check everything else that was taken apart to make sure they are put back on securely. Clear all codes, and leave it off (with key out) for a little while before trying again.

[egovreau]

Could be a vacuum leak, which will cause misfires across all four cylinders, which is probably a fair assumption.

There are at least five vacuum lines that connect to the manifold (on mine any way) and it's possible that one of them wasn't connected again, or has split in some way.

If you can get it to stay idling, you can spray starting fluid around the vacuum lines and see if the idle smoothes out

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[smirnoffandcoke]

I'm not understanding what the scope of work was, exactly. Why was the intake manifold removed for an ECU upgrade?

Did you remove the valve cover as well?

Please post all 7 codes with the code number and description.

I bought new injectors for it with the intention of putting them in and getting a tune straight after but this never happened.

When I had the injectors out a small amount of dirt got into the intake manifold (rookie mistake I know) so I had to remove it and vacuum out the dirt with a small concentrated hose. This is why all of the intake side was removed and cleaned.


VCDS-Lite Version: Release 1.2
Thursday, 27 April 2017, 23:42:19.


Chassis Type: 8E - Audi A4 B6
Scan: 01,02,03,08,09,0F,11,15,16,17,18,36,37,45,46,55,56 ,57,65,67,69,75,76,77

-------------------------------------------------------------------------------
Address 01: Engine Labels: Redir Fail!
Controller: 8E0 909 518 AK
Component: 1.8L R4/5VT G 0003
Coding: 0016711
Shop #: WSC 63351
VCID: 79856EE770C1
12 Faults Found:
17700 - Map Controlled Engine Cooling Thermostat (F265): Open Circuit
P1292 - 004 - No Signal/Communication - Intermittent
16684 - Shareware Version. To Decode all DTCs
P0300 - 001 - Please Register/Activate
16688 - Shareware Version. To Decode all DTCs
P0304 - 008 - Please Register/Activate - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 001 - Upper Limit Exceeded
18010 - Shareware Version. To Decode all DTCs
P1602 - 002 - Please Register/Activate - Intermittent
16687 - Shareware Version. To Decode all DTCs
P0303 - 008 - Please Register/Activate - Intermittent
16840 - EVAP System: Very Small Leak Detected
P0456 - 002 - Lower Limit Exceeded - Intermittent
16685 - Shareware Version. To Decode all DTCs
P0301 - 008 - Please Register/Activate - Intermittent
17769 - Shareware Version. To Decode all DTCs
P1361 - 004 - Please Register/Activate - Intermittent
17772 - Cylinder 4 Ignition Circuit: Open Circuit
P1364 - 004 - No Signal/Communication - Intermittent
17881 - Shareware Version. To Decode all DTCs
P1473 - 004 - Please Register/Activate
16486 - Shareware Version. To Decode all DTCs
P0102 - 002 - Please Register/Activate
Readiness: 0010 0001

[smirnoffandcoke]

Was the tuned ECU from the same year as yours? You have a 2002 A4. If it's anything like the 2002 models sold here in the US, those ECU will only work with other 2002 models. When swapping ECUs, make sure you get one from the same year to best ensure compatibility. Even then, you need to be careful about different immobilizers between the ECUs (unless it's been coded out with the tune).

If the only thing that changed is the ECU, check everything else that was taken apart to make sure they are put back on securely. Clear all codes, and leave it off (with key out) for a little while before trying again.

Yes the new ecu is out of an American 02 a4 B6 1.8tq also a manual like mine. The NEW ECU HAS IMMO DISABLED

Which software can I use to clear codes with my VCDS cable? VCDS lite requires a license and the laptop I'm using is a friends so I don't want to register the software on that pc.

The new ecu has more fault codes than the old ecu (12 vs 7)

[rocket1420]

I bought new injectors for it with the intention of putting them in and getting a tune straight after but this never happened.

When I had the injectors out a small amount of dirt got into the intake manifold (rookie mistake I know) so I had to remove it and vacuum out the dirt with a small concentrated hose. This is why all of the intake side was removed and cleaned.


VCDS-Lite Version: Release 1.2
Thursday, 27 April 2017, 23:42:19.


Chassis Type: 8E - Audi A4 B6
Scan: 01,02,03,08,09,0F,11,15,16,17,18,36,37,45,46,55,56 ,57,65,67,69,75,76,77

-------------------------------------------------------------------------------
Address 01: Engine Labels: Redir Fail!
Controller: 8E0 909 518 AK
Component: 1.8L R4/5VT G 0003
Coding: 0016711
Shop #: WSC 63351
VCID: 79856EE770C1
12 Faults Found:

Misfire codes

16684 - Shareware Version. To Decode all DTCs
            P0300 - 001 - Please Register/Activate
16688 - Shareware Version. To Decode all DTCs
            P0304 - 008 - Please Register/Activate - Intermittent
16686 -  Cylinder 2: Misfire Detected
            P0302 - 001 -  Upper Limit Exceeded
16687 - Shareware Version. To Decode all DTCs
            P0303 - 008 - Please Register/Activate - Intermittent
16685 - Shareware Version. To Decode all DTCs
            P0301 - 008 - Please Register/Activate - Intermittent

17700 - Map Controlled Engine Cooling Thermostat (F265): Open Circuit
P1292 - 004 - No Signal/Communication - Intermittent
18010 - Power Supply B+ Terminal 30: Voltage too Low
P1602 - 002 - Please Register/Activate - Intermittent
16840 - EVAP System: Very Small Leak Detected
P0456 - 002 - Lower Limit Exceeded - Intermittent
17769 - Cylinder 3 Ignition Circuit: Open Circuit
P1361 - 004 - Please Register/Activate - Intermittent
17772 - Cylinder 4 Ignition Circuit: Open Circuit
P1364 - 004 - No Signal/Communication - Intermittent
17881 - EVAP Leak Detection Pump: Open Circuit
P1473 - 004 - Please Register/Activate
16486 - Mass Air Flow Sensor (MAF/G70): Signal too Low
P0102 - 002 - Please Register/Activate
Readiness: 0010 0001

[rocket1420]

Yes the new ecu is out of an American 02 a4 B6 1.8tq also a manual like mine. The NEW ECU HAS IMMO DISABLED

Which software can I use to clear codes with my VCDS cable?

VCDS lite

[rocket1420]

Now that I looked up all of the codes for you, I would check out that MAF one first. What is your MAF reading?

[smirnoffandcoke]

Could be a vacuum leak, which will cause misfires across all four cylinders, which is probably a fair assumption.

There are at least five vacuum lines that connect to the manifold (on mine any way) and it's possible that one of them wasn't connected again, or has split in some way.

If you can get it to stay idling, you can spray starting fluid around the vacuum lines and see if the idle smoothes out

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The funny thing is it idles really well and seems to be running perfect but as soon as you drive it, it chokes with throttle and vibrates. It is drivable but you have to ease the throttle in very slowly (still causes miss)

I haven't​ seen any cracks in the vacuum lines since I've taken everything out a third time now... I replaced the rubber O-rings on every injector and a plastic seal that comes after the o-ring on one because it had a chip of plastic missing, probably from when I removed them.

[EuroxS4]

Did you replace the intake manifold gasket???Make sure there is no vacuum leaks.Also make sure everything is tight.Also were you running different injectors???or are you now running different injectors on a stock ecu??If thats the case the latency data in the stock ecu is for stock injectors.Other injectors need a few maps adjusted and dialed in.It will never run right.

[smirnoffandcoke]

Did you replace the intake manifold gasket???Make sure there is no vacuum leaks.Also make sure everything is tight.Also were you running different injectors???or are you now running different injectors on a stock ecu??If thats the case the latency data in the stock ecu is for stock injectors.Other injectors need a few maps adjusted and dialed in.It will never run right.

The gasket on the intake manifold was reused because I didn't have a spare. The stock injectors are in and the new stg2 ecu is in (I never ran the car with different injectors) The tune is for the stock injectors.

SOMEHOW the car runs better with the new ecu than the old one. I did not clear error codes in the car with old ecu or new ecu before putting it in so maybe the error codes from the old car it's from is still on it and causing my car to run bad.. I have no clue

[CyberPMG]

VCDS Lite should allow you to clear all codes. Try that. Let the car sit with the key out for a while. Then see what comes back.

[smirnoffandcoke]

VCDS Lite should allow you to clear all codes. Try that. Let the car sit with the key out for a while. Then see what comes back.

Ok so I cleared the codes with VCDS lite and now only 5 error codes show up (this is with the new ecu) It stills bogs with throttle and stinks of fuel after driving it.

VCDS-Lite Version: Release 1.2
Friday, 28 April 2017, 09:16:18.
Control Module Part Number: 8E0 909 518 AK
Component and/or Version: 1.8L R4/5VT G 0003
Software Coding: 0016711
Work Shop Code: WSC 63351
VCID: 79856EE770C1
5 Faults Found:
18057 - Powertrain Data Bus: Missing Message from ABS Controller
P1649 - 008 - Implausible Signal - Intermittent
17881 - Shareware Version. To Decode all DTCs
P1473 - 004 - Please Register/Activate
16486 - Shareware Version. To Decode all DTCs
P0102 - 002 - Please Register/Activate
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16686 - Shareware Version. To Decode all DTCs
P0302 - 001 - Please Register/Activate

I also tried putting the old ecu back and clearing the error codes. This didn't help at all and runs exactly the same.

My theory is one of the injectors has died and the reason the car is more drivable on the tuned ecu is more fuel is coming out of the 3 that are working. Also the fuel smell is stronger when the new is in... But I'm seriously​ guessing :/

[Charles.waite]

You sure you plugged everything back in and connected all the vacuum hoses?

[smirnoffandcoke]

This is my daily and I need it working badly. I will throw money in to fix it but I need to know what to get. Injectors? Spark plugs? Coil pack? The closest Audi dealership is 200ks away and I'm trying to stay away from them.

[smirnoffandcoke]

You sure you plugged everything back in and connected all the vacuum hoses?

Yeah I've spent many hours going over it and looking for that kind of stuff

[Gin+]

I'd start simple. Chill out with your favorite beverage. Verify the injectors are firing. Verify the plugs are firing.

The fuel smell and the fact you have a p0102-16486 code has me suspect that the ecu is freaking out and dumping fuel due to a short to ground but that's just my gut feeling so I wouldn't dwell on it. I'd consider disconnecting the maf at the very least and then maybe the 02 sensor to force the ecu into a closed loop situation to see if performance improves.

[Gin+]

Also, the *AK ecu's are typically from a 2004 model year.

[rocket1420]

Like I said, check the MAF.

[smirnoffandcoke]

Also, the *AK ecu's are typically from a 2004 model year.

Cheers for the advice, I'll try disconnecting the maf tomorrow first thing. As for the injectors and plugs I'm not sure I'll be able to test them myself.

The weird bogging and what seems like poor combustion is noticeable on both the ECUs so I'm guessing it's not a software issue. I'd really like to know if switching between 2 ECUs can cause the car to run so poor.

Also there is a check engine light with the new ecu but not with the old. So maybe the different model number "ak" instead of "b" is important. I did a fair amount of research before getting the new ecu and from what people said its only the immo that can be an issue.

[Let it snow]

Try a throttle body alignment if VCDS lite can do that. Worth a shot.

[AudiA4_20T]

OK here is what I think. Assuming everything is fine, I think that when those codes were initially thrown, the ECU went into a sort of "safe-mode", dumping fuel until you get it looked at. For all we know, the ECU had those codes before.

I would recommend you finding an ACTUAL VAGCOM and scanning the full vehicle and clearing everything. It sounds like your ABS is involved, etc etc. You need to clear out everything, do a throttle body adaptation, and start it.

Ah, actually in the absence of a real vag-com, you can take leads off the battery and touch them together for a few seconds. This should clear out anything stored in the ECU. Then re-attach them to the battery and try again.

[smirnoffandcoke]

OK here is what I think. Assuming everything is fine, I think that when those codes were initially thrown, the ECU went into a sort of "safe-mode", dumping fuel until you get it looked at. For all we know, the ECU had those codes before.

I would recommend you finding an ACTUAL VAGCOM and scanning the full vehicle and clearing everything. It sounds like your ABS is involved, etc etc. You need to clear out everything, do a throttle body adaptation, and start it.

Ah, actually in the absence of a real vag-com, you can take leads off the battery and touch them together for a few seconds. This should clear out anything stored in the ECU. Then re-attach them to the battery and try again.

Ive removed and touched the leads, as well as a manual throttle body adaption afterwards. My missfire persists and I still get the same DTC's when I check with VCDS lite.

[AudiA4_20T]

Ive removed and touched the leads, as well as a manual throttle body adaption afterwards. My missfire persists and I still get the same DTC's when I check with VCDS lite.

well then either your plugs are actually fouled out, or everyone is right and you missed a ground or vacuum hose.

[rocket1420]

ive removed and touched the leads, as well as a manual throttle body adaption afterwards. My missfire persists and i still get the same dtc's when i check with vcds lite.

Check. Your. Maf.

[smirnoffandcoke]

Runs crap plugged in and unplugged. I tried to use VCDS measuring blocks but really I have no idea what the figures should be.

[heywier427]

If you re-used the intake manifold gasket, it can definitely be leaking. Get a new one, or for now, lightly coat the old one on both sides with silicone and re-install.

The car worked before you did anything to it, so you f'd something up. No need to throw money at it, unless that means paying for someone else to fix it.

Not sure if you can mix up the connectors on the n249 and n112 valves under the intake. That may cause problems.

Get a cheap cigar and blow into a vacuum hose. With the engine off!

Youtube, diy smoke test. The one below is the crudest, but you will probably have the stuff to do it. Choose one you can do.

https://www.youtube.com/watch?v=KfB9r223ZUQ

[smirnoffandcoke]

Thanks I will give that smoke test a shot. I hear the old vacuum lines crack easily.

The possibility of mixing the connectors under the intake manifold actually came to mind a few times... I couldn't find any pictures online showing where the coloured connectors sit. Im sure they are in the right position because the wire is just the right length on them all (ex the throttle body cable which is only just reaching and is pulled tight)

As for not spending money... frustration from not being able to make any progress on the missfire caused me to buy R8 coil packs and spacers as well as spark plugs which I'll get in a couple of days. Im thinking still about an eBay maf sensor but if ive never touched it so how could it suddenly die..

I tried switching coil packs around (labelling them 1-4) then checking the DTCs with VCDS lite and clearing error code afterwards. I had missfire on #2 and #1 as well as multiple/random missfire and that cursed maf low signal code. Then switched coil pack #4 with #1 and 3 with 2. The only difference is I got a missfire code on cyclinder 4 (still with the random/multiple and cyclinder 2 missfire)

I'm just not sure if I'm doing damage by driving it like it is 😷

[smirnoffandcoke]

FINALLY fixed. Bad coil pack was the issue. Apparently such a bad missfire can only be a spark problem not a vacuum leak. I don't know how a coil died if I've never touched it and the car was just sitting for 3 weeks before.

[EuroxS4]

FINALLY fixed. Bad coil pack was the issue. Apparently such a bad missfire can only be a spark problem not a vacuum leak. I don't know how a coil died if I've never touched it and the car was just sitting for 3 weeks before.

They fail all the time it's a very common thing on these cars.So common I keep 2 spares in my glovebox lol

[georgio3gr]

Use tfsi coils+adapters and you won't have a problem again...

[EuroxS4]

Use tfsi coils+adapters and you won't have a problem again...

They still fail,maybe not as often but have the same design and internal parts.


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[georgio3gr]

They still fail,maybe not as often but have the same design and internal parts.

Maybe there's another problem... I have mine with full gt28rs setup for two years without changing them... R8 red coils...

[A4SoftWalker]

I've had 2 out of one set of 4 TSFI coils fail before I went BT. Right at the 3 year mark. Less than 30k miles.

[EuroxS4]

Yeah they still fail.I see it all the time!!


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[Charles.waite]

Nah Brah! My 07k coils have almost 30k on them and are going strong.

[georgio3gr]

we (i and friends) use them at five bt 20vt engines, some have more than 60000kms with them... They just need new sparks (we use bosch f5dp0r) every 15000-20000kms. If you leave the coils with old sparks, they have a drop at their performance and finally fail..

[EuroxS4]

Why Bosch??Why not Ngk? bkr7e is a solid plug that a lot of people use on big turbo applications.Yes I do agree spark plugs are a factor


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