ECM/IGN. fuse blows when driving...
I'm helping a friend with his 1991 GMC sierra 5.7 TBI which is now actually a 305ci Rebuild I installed for him. Then I installed a used 700 tranny soon after due to loss of 1st and R. Ok, runs strong he loves it, as do I, but we still haven't put not one highway mile on engine due to the fact that the ECM/IGN fuse blows and has blown at the same EXACT driveway 5 times consecutively! I can pinpoint when the fuse will blow. Soon after the truck shifts into high gear. Replace the fuse drive it back home, plus around the block cpl times plus 15-20 minutes idling and the fuse won't blow. Take off down the road and bam same spot every time fuse blows. I've been around the World, went to 2 World Fairs and watched Buzzards mate, but I ain't ever seen anything like this!!! What'* up? I would deeply appreciate any help at all! Thank you.