Hi, had a flat battery in the vn and used another battery and to start it and was changing them over while car was running and I got a spark from around battery area,car cut out then havent been able to start it since,it does turn over and will occasionally lightly fire and then get a small backfire through the airbox but still wont fire.also i have noticed a wire off the negative battery terminal with a computer protector small box,just wondering if I have knocked this off also ,so was
wondering where the other side of the wire connects to.
Ok well to start off switching batteries while the car is running is plain stupid the things your going to have checked and maybe replaced is as follows : the starter motor the ecu the coil pack for v6 distributor and cool v8 and the alternator
Cool = coil
However all is not lost, try checking all the fusible links first, there is a little black cover with 5 main fuses in it, down low between the battery and the the main relay panel, take of the little long black cover and check all five main fuses, then check all your fuses under the dash especially the ecu fuses, if all of these are ok then check the ecu relay under the big black cover between the shock tower and the battery, switch out the ecu relay and with another and test the engine, if still no joy I would imagine you have fried the ECU, I would borrow one from one of your friends first and put it in to see if it will run, if so take your old ecu to the wreckers so they can match the numbers and get yourself another one. Hope this helps - Jon.
Of coarse I'm right I've been working on cars for 10 years lol but anyway hope we have helped