7.3 won't start...gauges maxing out

[Dave mcleod]

After sitting for one day my 2002 f250 7.3 refused to start. When ignition switch was engaged, all gauges went to maximum and then back to zero. The motor turned a few times but quickly stopped and didn't turn again. Both batteries have been replaced in the last 2 years and I've never run them down completely. I checked the charge and both batteries were low so I charged them for several hours and she started up fine. While running I checked the batteries to see if the alternator was working and it was. After sitting overnight I had the same problem. Any insight would be helpful. Not the batteries or the alternator I believe.

[melmount]

hows the battery cables? They get corrosion on the inside near where they meet the batteries? Then maybe unhook the selenoid to the starter on pass fenderwell. maybe somehow its drawing current all the time to the starter. Gotta be in the battery to starter area for draw?

[justinmix]

It could still be a battery issue. You could have a shorted cell drawing power. Best way to tell would be to make sure the batteries are fully charged. Take off both negitive cables and try it the next morning. If it turns over great and starts up then you have a battery draw. If it cranks slow then you have a shorted cell in a battery. You really need a good battery tester to check out the batteries. Most auto parts stores have a good digital tester that will check for shorted cells.

[belz]

If one battery is bad it'll drain both since they are connected. Have em tested at the auto parts store but be sure to disconnect them from one another when testing or they will most likely test good. I just changed my alternator and battery. The first guy tested the batteries and did not disconnect one so they tested good. I made them test again and disconnected the optima, of course the other battery was no good.