Hi. One of my Audi's - 92 V8 4.2 ltr auto Quattro has electrical problems and won't crank and if starter interlock relay is bypassed will crank but has no spark. Car was going and parked over night. Next day it would not do any think from key. Starter motor is in good condition. Suspect the problem is with security system/central locking which has imobillized car. Have wiring diagrams for 1990 model but 1992 car if different. Hope someone can help me with diagrams or hints to get car going. Getting very Stressed !