Car Starts, but dies quickly after running terrible
 

Car is a S4 with S5 turbo swap using the S4 harness and ECU.

Alright, so car was running great until one very cold morning a few months ago when I went out to start it and the throttle stuck and left the engine at about 4500 RPMs for 15-20 seconds until I could pop the hood and yank on the throttle cable. It idled back down to normal, but the computer was going BEEP......BEEP.......BEEP. I turned off the car and went to start it again and the battery was pretty much dead from the cold and being old so it didn't start.

I pulled out the battery to put it on the charger and while I was using my the ratchet, it slipped and crossed the battery terminals for a split second and sparked. I ended up buying a new battery and could get it to start, but it was running crappy like it was only on one rotor. I had it parked for the last couple of months and am now starting to work on it again.

Today I did a compression test and without it being warmed up it was in the low 90's all faces on both rotors. I managed to get it started the first time with some clean plugs, but it was running pretty crappy and after 5 seconds stalled out. I can get it really close to starting, but not quite there. It is pretty flooded at the moment and the spark plugs are very wet. If I clean them off and put them back in it kinda repeats in that it will start temporarily but die rather quickly. I can't keep it running by pressing the gas.

I have tried changing both coils. I checked the AFM and the connector is on solid. I checked all of the fuses. Could I have burned some stuff out when I crossed the battery? Any other advice for things I should check or try? I have been searching, but most threads are related to the AFM and they are able to keep the car running with gas pedal depressed.

I am going to attempt a pull-start to see if that clears anything up.

Thanks,

Justin

Check all your main fuses like EGI and what not but idk man it coulda be a lot of dif things. although if you're only running 90 on a compression text you will need a rebuild soon.

also you coulda blown a seal resulting in your fuel leaking into your engine causing it to flood requiring a rebuild

Blown a seal that would leak fuel into the combustion chamber? The fuel is supplied by injectors, so unless they leak, there's no other way for fuel to end up there.

And he said he checked his fuses. Anyway, it's hard to say what could have been damaged when the terminals were shorted. Usually things go bad when the battery is hooked up backwards, but don't count it out. Checking the ecu is pretty easy since you'll clearly be able to see burned components on the board. If you're going to start somewhere, check it first. Beyond that, hook up a tach light to see if you're getting spark on all plugs.

Well I got it running after swapping out the coils again, got new battery terminals, removed the FCD, and cleaned the spark plugs. It's not perfect, but it's running about 90% or so. Thanks for the ideas. I am going to add the FCD back in and see if that pooches it again. I've heard a bad FCD will put it in permanent fuel cut.