Electrical issues are the worst because of their often intermittent occurrences.

I scanned for codes and got four.

1. 18010/P1602/005634 - Power Supply B+ Terminal 30: Voltage too Low

2. 17968/P1560/005472 - 17968 - Maximum Engine Speed Exceeded (Engine Warranty VOID! ☺ )

3. 17967/P1559/005465 - Throttle Body (J338): Fault in Basic Settings

4. 17967/P1559/005465 - Throttle Body (J338): Fault in Basic Settings

Terminal 30 low voltage appears every time the battery is disconnected. I'm fairly certain I cleared codes before starting the car for the first time so this could be related?

The other two I believe are due to me mashing the throttle while getting the car started. I'm surprised to not see any misfire codes..probably confirms that this is some weird electrical issue and not something mechanical like a blown coil pack. Ugh.

I've since cleared codes, started the car (it fires right up like normal now), had it die and no codes have appeared yet.

Today I will be going over the wiring and I'll try to take some logs to see if anything looks peculiar when the problem occurs.

Does anyone have a suggestion for where to start looking on the relay panel?

 

No clue where to start on that, but I do have some spare relays I pulled from my parts car. Let me know if you want a couple for swapping out.

 

^Thanks, much appreciated. I've got a few relays lying around myself. I happened to have a spare fuel pump relay, swapping that out didn't fix the problem. I was really hoping that was going to be the problem, it would seem to make sense. Fuel pump relay clicks, engine cuts out and dies. But nope.

I did some logging and didn't see anything that would indicate a problem. As the engine starts to die air g/s decreases along with fuel injector ms. Timing looks normal, knock voltages look fine..battery voltage is close to 14v when running.

I'm not getting any repeat codes from the engine now. The only code I was able to pull was an HVAC code.

01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent

Maybe a faulty ignition switch...

 

You mentioned that you could hear a relay clicking when it started to sputter. Does it still do this? Have you identified which relay is clicking? I would try to trace the signal for that relay as a place to start.

I'm not sure about the 1.8 engines, but after working on my V8, I've found that there isn't much required to actually run the engine. You may want to try tracking down those signals and use a digital multimeter to see which is faulty.

 

Yes, there is a definite clicking when the engine shuts down.

I swapped ECUs and the problem seems to have gone away. I'm not sure how happy I should be. That means something is wrong with my chipped ECU..

Though I'm glad the car runs on a stock ECU. I'm at a loss for what could have happened to the other ECU though.

 

Took it for another drive and everything remains fine with the stock ECU. I am getting an occasional CEL for the vehicle speed sensor. I was getting that code before but it wasn't actually tripping the CEL, so thats a little strange.

I should note that while I was installing the headlight relays on my car I put the chipped ECU into my dad's 99 1.8T since he had always wanted to try a chipped ECU. His car is an automatic so I recoded it for an auto and it ran great. I put it back in my car when I finished the work, recoded it again for manual, drove 20 miles, and started having the clicking relay and engine shutdown problem.

I guess the next test would be to put the chipped ECU back into my dad's car and see how it runs.

EDIT: I'm also no longer getting the "Signal for Duration of Ignition Off Time" code with the stock ECU in place.

 

Well it must be the ECU. I just put it back into my dad's A4 and had the same problem on his car. Starts up, runs for a few minutes, engine starts to stall and eventually dies.

No idea what could've happened to it.

 

*crickets* *crickets*

Here is the final set up of the power distribution block. It gets its power from the switched 75x post.

From bottom to top:

2A - Fog light relay power (replaced power from headlight circuit)
10A - Power for fogs (goes through the fog light switch)
5A - Driver's headlight relay
5A - Passenger's headlight relay
2A - iPhone charger (already has a 1A fuse in line, didn't want to bother with taking it out.)
2A - Underdash lights power (through Funk button)

Note: I rechecked the fuses and lowered the headlight relays to a 4A fuse from a 5A shown in the picture and the fog lights from a 10A to a 7.5A fuse.







And the result: A headlight switch that should never melt again and independent fog lights.

 

I'm not sure why the chipped ECU spontaneously went bad. Have you contacted the tuning company?

The fuse block looks good, though it's a bummer to have to remove the knee bolster to access it in the result of a blown fuse. If I understand your circuitry correctly, you may want to re-evaluate your fuse sizes. If you're running the stock 55W bulbs in your fogs, the 10A fuse you have used will be cutting it too close.

At 12V, the current will be ~9.1A. Generally fuse sizing is 1.5x the expected current. It looks like you've used 14 awg wire, which has an ampacity of 20A, so you're nowhere near exceeding the wire. I would probably run a 15A fuse for the fog power.

 

I don't mean to take you off subject of your ECU gone bad, but did you use this DIY below to install your fogs? what did you make your prackets out of and how are your brackets mounted from the back?

AudiWorld Tech Articles