I have an 03 excursion 7.3L and twice now it has not started and I had hook up the jumper cables. I am convinced its one of the batteries, which I plan on checking this evening, but I am puzzled on the scenario of when it doesn't start. I would like to know if you guys agree with on the battteries being the issue or possibly something else.

I did a search on the forum and read many topics. When I get home tonight I will check the voltages of both batteries and the alternator output. I checked the alternator this morning before starting the truck and it was cold to the touch.

The truck started fine as usual I drove about 5 miles and parked, about an hour later I tried starting the truck and it would not crank. Everything turned on lights, radio and guages. When I turned the key the starter would not crank. The batter light has never come on. I checked all fuses thinking possibly the starter fuse was bad, but all checked out ok. So I decided to hook up the jumper cables, they hooked up no more than 30 seconds and the trucked fired right up. My battey terminals were corroded so I thought the batteries might not be getting a good charge. I cleaned them and coated real good. No problems for about two weeks.

The truck sat from Friday evening to Sunday morning. It fired right up yesterday morning, I drove about 5 miles and shut it down. It started right up 20 minutes later. I drove about 15 miles shut it down for 30 minutes and it would not start. Same thing as before I had power to everything just wouldn't crank. Hooked up the jumper cables fired right up.

I just don't understand why it will start, then it won't start. I will confirm the alternator is charging this evening.

Let me know what your thoughts are and if it turns out to be the battery(s) what brand and size should I purchase.

Thanks

 

Sounds like maybe a ground wire or the battery cable going to the starter. Or a starter problem. When starters go out they can draw more current to turn over. A Curtis

 

I would verify the Alternator is charging before doing anything as you said, then go from there. Can verify your connections at that time as well, read the voltage from the battery post, then read it from the cable connector, should be reading 14 volts or so when running.

Edit: If the alternator is bad, the batteries tend to recharge over time sitting, but after you run it, especially when glow plug system is engaged and headlights are on, you use up all your battery reserve, so it won't restart.

 

I agree with Tom, except I would have checked the connections of the batteries first, if you can move them there is a problem there..

 

The connections at the batteries are tight and there is no corrosion. They were cleaned no more than two weeks ago.

If the alternator was bad, wouldn't the indicator light in the dash come on?

 

Hate to sound like an ****, but was it tight two weeks ago when you did the checks, or are they tight today ( experience here speaking, running into the same problem as I type. Something about my truck and them damn terminals).

Next, are you getting even a click when this happens??

Yes, normally when the alt starts getting week, the light will come on intermittently, and then just on when bad.

 

The terminal connections were always tight. Even before I cleaned them.

The indicator light has neve come on to my knowledge.

I don't think the start clicks at all, the fuel pump turns on. I think there may have been a click yesterday from the solenoid by the fuel filter housing or from under the dash, but I can't remember, which one. I was in Lowes parking lot in the pouring rain and was trying to get it started as fast as possible.

 

I would put a volt meter to the truck while is running, 14 volts, alternator is good, otherwise, reading 12 or what have you, is not charging, bad. Were no check engine lights on my buddies tuck a month or so ago when his failed.

 

Where is the best place to check the alternator voltage from?

 

big plug on top of alt is voltage out to batteries.

 

My battery light started comming on intermitently and after awhile jus stayed on. The truck started slowly having hard cranking and eventually ran down my batteries with lights and plow motor especially. I had them load tested hoping I could get some pro rated discount for the three year old 100 month Motorcrafts but they tested good so that brought me to the bad alt.
She was only putting out 11.9 V and would only jump .5 or .6V even at 2000 plus RPM. Solution--- DB 220 amp high output. Now all is good
Thanks again to this site for the fine intel

 

Can anyone help! My truck well not start the batteries are new and the starter they said was good and the alternater was good too. when i put the new batteries in about 3 months ago it ran fine but now it well not start. please help

 

Well bad news, I need to get a new multimeter. I went out tonight to check the voltages and the meter wouldn't work. Hopefully tomorrow I can get this figured out.

 

You cant check the voltage right away, you need to wait for the glow plugs to turn off, which can take 2 minutes after start up.

 

I disagree, you need 10.5+ to start, and your glow plugs will still be working normally when you turn your truck over, so, IMHO youshould be checking as you are turning over and the glow plugs are most likely still working.