Have 87 240 gl normally runs fine had corrosion on positive battery wire,the smaller one that goes to the driver side firewall, cleaned off with water and baking soda. Guess I sorted it out while it was wet, test light shows it as hot. Car won't start, fires fine with starter fluid but won't keep running. Plenty of battery power, starter works fine. Is it FI relay, where is this relay located what does it look like? Where/how to trouble shoot, Any other suggestions?