2002 X 7.3L diesel

Recently my wife's vehicle has been having electrical problems. It started with hard starting. I replaced the starter and big difference. The hard starting came back in another week or so. I had the batteries checked at Advanced Auto They said that one was good and the other was at 60%. I replaced the one at 60%. All is well for a couple of days and then more starter dragging. I went ahead and replaced the other battery which was less than 2 years old. All is well for a few days and then the starter started to drag again. I checked charging voltage and my meter read 10.5V. So, I replaced the alternator (with batteries disconnected). I go to start the vehicle and it won't start. It turns over nice and fast but does not fire. Something odd that started to occur at some point during this whole process is that I can hear the radio/CD player cycling. I think it actually cycles turning on and off when I try to start the vehicle. I am reading 11.92V battery post voltage right now while not running. But I have been trying to start the vehicle. I'll leave it on charge for the night and see what it is in the morning. For now I have to got to work but wanted to get this posted for the great minds out there willing to help a poor soul out.

Nelson

 

The batteries should have been replaced together. When you replace them one at a time, you more often than not end back at square one.

If the PCM sees less than 10.5 volts the injectors will not fire. Yes, this can happen even though you have two batteries.

This actually happened on a 2005 6.0 F250 I was working on. Two guys I know called me and said the truck had a crank, no start condition. I had them walk through a few steps, but still to no avail. I ask about the condition of the batteries, one was new and the other was sulfated and on it's last leg, but the truck ran before . I tell them to disconnect the batteries and charge them. They left the batteries connected and the truck STILL wouldn't start despite them "charging" the batteries. I come over pull the connections on the driver side battery, charged the battery for 30 minutes, and the truck started like nothing was wrong.

The owner then had to go out and buy two new batteries like I'd told him to before.

So I would pull the batteries, slow charge them individually, and go from there. Make sure the connections are clean and fully seated as well.

 

Thanks Toreaor. I appreciate the insight. I shall try this when I get home from work in the morning.

Nelson

 

I got my batteries up to a good charge. The truck still did not start. Still had a couple of odd electrical gremlins like the radio/cd player cycling and gauges doing some funny things when I would turn the key. These reminded me of when my Vehicle Security Module (VSM) went out. When that happened, I would disconnect and reconnect the battery to reset the module which would last for some days until the module would again fail. So I disconnected and then reconnected my batteries and tried to start with no change. I did the same thing again and this time I cycled the key when the batteries were disconnected to ensure any charge within the module(s) got drained. It started right up. Maybe someone out there can explain exactly what happened. The big thing is my wife has her vehicle back. Thanks.

Nelson