Cadillac Repair: 1989 cadillac deville 4.5, no start, dash problem

Question
Last Monday battery was dead we put water into it because it was low and charged it, everything was fine but we also put the wires to charge it on both terminals and i think it may have done something to the computer, the fuel data center keeps going from mpg to inst etc. rapidly.  Then today no start; seems like not getting fuel.

Answer
Hi Michael,

       That is the strange thing with computers...when the power is interrupted and then restored they reset but not the way you want them to.

       With the fuel data panel issue what I would recommend is to disconnect the negative battery cable and turn the headlights on to drain the power from all the modules. After 15 minuets turn the headlamp switch off and reconnect the battery cable. Then turn the key on or try and start the engine and the FDC might return to normal.

       As for the no start...find someone with good hearing and have them place their ear near the fuel filler neck after removing the gas cap. Turn the key on and for 2 seconds you should hear the fuel pump run and then stop. That won't guaranty that the pressure is ok but at least you know the pump works. If you have a spark checker install it into 1 of the plug wires and crank the engine and see if there is spark. Another way to do it is to remove a plug and touch it to metal on the engine away from anything fuel related while attached to a plug wire. Crank the engine and see if there is spark. You will then need to troubleshoot the system that isn't working or hook up a fuel pressure gauge to the fuel rail schrader valve to verify pressure.

       Other things that can cause a crank no start are a bad computer or throttle position sensor stuck in the wide open position.

       Hope that helps, Bill