Had some body repair on my 2003 Beetle TDI .The body repairman disconnected the battery to protect the ECU when doing some welding.Since then fuel consumption is up by 1.5 litre per 100 km and I see alot of black smoke from the exhaust during accelaration. I am equipped with OBDII software and could change fuel parameters but I need to know what to change,help!

gill.sauve@videotron.ca