I have a 2000 A4 1.8t. Today when I went to start it it just cranked, not start. Fuse 29 was blown and it did this once before. However this time when I went to put in a new fuse it immediately blew that one. In my quest to find out what (Computer Engine Control fuse was actually powering seeing as there are 3 or 4 of those fuses, I pulled the cover off the black box that houses the ECU. Next to the ECU are two larger relays and the one by the firewall was warm to the touch. Pulled that, put a new fuse in and now the fuse doesn't blow but the car still doesn't start. Can someone throw me a bone here and tell me what that relay is powering. I'd really like to go get a bloody mary but can't until my car starts.

 

Did you put a new relay in? Sounds like you just pulled the relay without replacing it...

 

It was the wires going to the cylinder #4 coil. All fixed now.

 

How did you figure out the problem ? I've the same symptoms fuse 29 keeps blowing.

 

this is driving me nuts ..

this is what i understand ..

car started from cold, ok .. car ran fine to shop 1 (1 m) .. after shop 1 car started ok, but sluggish .. car ran to shop 2 (1 m) .. after shop 2 car started ok, but sluggish ..

car then ran for a while (1-2 m) then cut out .. car will not start .. customer left car where it died ..

vagcom shows brake light switch open circuit .. new brake light switch on order ..

vagcom does not show engine m u ..

fuse 29 blown ..

replace fuse 29 .. car starts .. runs badly for few seconds, petrol heavy .. fused 29 blows ..

replace fuse 29 .. blows again almost straight away without even trying to start engine ..

any ideas ?...

has someone seen this before ?.

thanks ..

 

sounds like the fuel pump put a bigger fuse in it and be done with it, i did it fine wirh 15,000 miles and fuse never blew again

 

Andrew thats a bad idea. Puting a higher rated fuse just places stress on something besides the safety mechanism. Sure you may get away with it, but the issue is still there and can cause melted harnesses, fires, blown ecu etc.

 

i mean if its the fuel pump who cares burn it out

 

What if it doesn't burn out the fuel pump... Have you ever over juiced a wire a felt it get hot and melt? now that one wire could get hot melt and not just itself but all the others around it causing a major issue.

 

the last fuse i blew was a green 30a (there was no 20a ones available, and i was being lazy) .. AND i did not even try turning the engine over .. i heard the fuse "pop" as i turned the ignition key from 0 to 1 ..

i also doubt if fuel pump .. apparently, it was replaced a couple of years ago at an audi dealership ..