Had a setback this weekend on the S4 project. We have had a lot of rain and flooding in New York over the last week. I figured my parking spot on a hill was safe, but did not know of the attack the rain was planning from within the car. I had previously cleaned out the cowl drains but it appears either trees or mice piled enough debris back in to fully plug it up. When I went to start the car Saturday I was greeted with a dead battery. No big deal with the car sitting for more than a week. As I got out I noticed the passenger side foot well was filled up to the door with water. Would have been less of an issue if the ECM wasn't mounted below the passenger's feet.
After several hours of removing trim, seats and eventually carpet the only real damage looks to be to the ECM itself. I opened it up and there was already a lot of corrosion and green connectors after 4 days of partial submersion. Luckily there were no other connectors below the water line, but I am not sure exactly where the water came through the dash and what may have gotten wet. We had two nice days of sun which did a good job of drying the car out after bailing and shop vac'ing. The carpets have been scrubbed and are hanging to dry now.
Trying to find a 21 year old ECM has not been successful yet, but I'm sure it will work out. The main concern right now is resisting the temptation to never put the interior back in and making sure nothing else got fried. Not quite a true flood car, but I got to see how much damage water can do quickly. It seems like every time I get close to doing a fun car project I get to deal with a pressing issue instead. As always, could have been worse.
Check the drains in your older cars. In this case Audi had installed a rubber flap to keep engine compartment gunk out of the cowl, but it ended up causing more issues than it was worth.
You wanted an 034 EFI ECU anyway, right? :)
Terrible formatting fixed above, I'll get this forum figured out at some point.
I would love a lot of 034 Motorsports things, but damn do they want real money for them. Every time I finally get set to buy some more hp that car finds something else it wants. The good news tonight was that all the other electrical functions seem to work as intended.
Sad to say but the S4 is done for according to the insurance company. ECM's for these are quite hard to come by and they were not too keen on dealing with a potential flood car. Both sad to see it go and relieved to be down to one less project car. Mostly upset about the number of hours I have in the car and the memories of a good 4 years coming to an end.
I remember that the ECUs on those would flood out even if you left the window down a bit in the rain; it's just in a really bad place in the floorboard for flooding out.
Sorry to hear that the car is toast.
old_
Reader
6/23/14 11:23 a.m.
Buy back, megasquirt, win.
Is it just the ECU? If so, then Megasquirt or http://store.034motorsport.com/products/034efi-engine-management.html is an easy solution.
Or did it flood other stuff too?
The insurance company did you a favour IMO. After my urs4 debacle... Audi: NEVER AGAIN! 
You bought a bad one. I tried to warn you. Blaming Audi for that is ridiculous.
I don't remember the story on HiTempGuy's "bad" S4 but do agree they can be maddening. I did try a salvage ECM, but it wound up having a similar issue, with a direct short across a few pins. Taking it apart didn't reveal anything obvious and the next cheapest one was $600, which is when I got the insurance involved.
As a happy ending I did buy it back from the insurance company and it should be going to a new home with someone who known the fun of owning old Audis. I am happy to be rid of them for awhile and clear the house of Audi parts. What really pushed me over the edge was when I realized the amount of time the car had spent sitting waiting on rare or unique parts or time to fix things over the last two years. Its usage time was getting to be similar to a pleasure boat.
Many of the parts are simply NLA, like the bumper cover. I had a friend who's side business was parting these cars out. When I needed something he'd just leave it on my porch.
If it wasn't for him there's no way I could've kept my car going, cost and parts wise. I ended up selling it, it was just requiring too much of my time.
The UrS4's are awesome cars but are beyond using as your sole DD.
