b5Audi1.8

So let me start off by saying i joined this forum specifically because of this issue i have been having. I am fairly mechanically inclined and typically do not need this level of assistance; however i am at my wits ends.

The vehicle is a 1998 Audi A4 Quattro 1.8t with the 3 pin coil. About 2 months ago the vehicle caught on fire following a valve cover gasket replacement. Im assuming oil seeped down and the cat caught fire. The fire came up around the number 3 and 4 coils; melted the wiring to the coils, engine cover, and that seems to be the extent of the damage. Originally, after rigging everything back up, the number 29 and 32 fuses would blow once the ignition was turned on, not turned over. The vehicle turns over fine, just doesnt fire, no spark, etc.

Since then, i have replaced the 4 coil connectors with new ones, and roughly 18 inches of wiring back from the coils just for good measure. Fuses still pop; except now the 32 fuse only pop maybe ever 2 or 3 tries? Next step, i thought maybe the ECU fried when the coils melted together, possibly sending current back through the wiring. Swapped the ECU out today, same issue. 29 pops immediately upon turning the key. I am completely lost. Obviously there is a wire or something shorted out somewhere, however the wiring all around the original fire has been fixed. Other than melted black plastic down between the cat and engine block, havent cleaned off yet, there seems to be no other damage.

Any and all help will be GREATLY appreciated, and im sure that somebody here can help me solve this annoyance, i love the car too much to part with, If i left any information out there is needed to aid in tracking this issue down please let me know and i will happily supply it.

David.Norton

Well, fuse 29 supplies a bunch of stuff around the ECM, 32 supplies the 12V to the coils. I don't see any mention of the power output stage, it is the part between the ECM and the coils, and sits in the air cleaner box (to keep it cool). I would start by pulling both the ECM and the power output stage and see if it still blows the fuses, if it does then there is still something wrong with the wiring. My worry is that if the power stage is blown, depending on the failure, it could have taken the ECM with it (I only think that because of the fuse blowing). Anyway, good luck with it.

b5Audi1.8

Thank you for the reply. I did forget to add in that before i rewired the new coil connectors in, i unplugged wires going to the ECU, fuse did not blow. Upon plugging the wires back into the ecu, i disconnected all 4 coils, and the output you are referring to on top of the air box, i always thought this was an ignition control module of sorts, anyways, fuse blows with the coils and the module on the air box disconnected. Im starting to believe wiring further in may be damaged and causing the short. On my next day off i plan to cut away all of the wire covers and insulation and follow all the wiring back from the ecu to check for shorts, melts, burns, etc. Again, thank you for the reply. I was beginning to think that nobody was going to pitch a hand.