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Discussion Starter · #1 ·
I have a 2000 7.3 PSD and this morning I started it and it cranked fine then about an hour later I went to start it then it cranked once and ALL electronics died radio, lights, everything. So I mess around connecting and disconnecting the batteries then the interior lights came back on and I went to start it and it was almost like it was trying to start on one battery. The driver side battery is a week old and the passenger side one is old but still VERY good. Could it be the cables maybe? Bad ground? Any and all ideas are appreciated!!!
 

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First, you should always replace batteries in pairs. The older one (even "VERY good" ones) can drag down the new battery.
Cable connections are suspect if you didn't clean the posts and clamps (that should be done EVERY time they're disconnected). If there's any corrosion evident, it could have crept into the cable, turning it into green goo. But it sounds like you haven't cleaned the posts and clamps. A battery post/cable cleaning brush is an essential part of your toolbox.
 

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Get one of those lighter port voltage indictators, bout 10 bucks, and know your system voltage patterns. It takes two good batteries to start, low voltage starts, very low during glow plug assisted starts drags starters down and kills them. It all starts with good batteries and cable connections. Including the connections inconvenient to see, like starter connections and grounds out of sight.
 

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Check the alternator output. You can loose a diode and it will not trip the ALT light but won't charge the battery's properly. Had that happen X 2. Alternator should be putting out close to 14 volts. DENNY
 
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Just went through this with my father's '99 F350, Checked batteries and cables/connections then installed new batteries, same issue. Decided to change starter to Denso 2 bolt starter, I previously installed one on my 2000 F250 and still amazed of just how fast it turns a 7.3 over. Anyhow, once I removed the original Mitsubishi starter I found one of the 2 screws that hold the solenoid to the starter was missing, the solenoid almost fell off in my hand. Glad I already had an upgraded starter ready to install, once installed starting issue was gone of course. Hope this is helpful

BTW, before changing out batteries I put a DC clamp meter on battery cable running to starter, old starter was pulling over 875 amps while attempting to start, 550 amps so is said to be about average.
 

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Discussion Starter · #6 ·
Check the alternator output. You can loose a diode and it will not trip the ALT light but won't charge the battery's properly. Had that happen X 2. Alternator should be putting out close to 14 volts. DENNY
Just went through this with my father's '99 F350, Checked batteries and cables/connections then installed new batteries, same issue. Decided to change starter to Denso 2 bolt starter, I previously installed one on my 2000 F250 and still amazed of just how fast it turns a 7.3 over. Anyhow, once I removed the original Mitsubishi starter I found one of the 2 screws that hold the solenoid to the starter was missing, the solenoid almost fell off in my hand. Glad I already had an upgraded starter ready to install, once installed starting issue was gone of course. Hope this is helpful

BTW, before changing out batteries I put a DC clamp meter on battery cable running to starter, old starter was pulling over 875 amps while attempting to start, 550 amps so is said to be about average.
Sorry I took so long to reply but it was the batteries to my surprise which was really weird because everything shut off then I reconnected it a couple times and everything came back on (this was before I replaced the batteries) also BBranch you said that you installed the two bolt starter on your 2000 my question is did the two bolt starters shaft stick out farther than the three whole starter? Because whenever I look online for one it has a longer shaft than the three wholer and I don’t want to waste money on the wrong thing
 

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I have a 2000 7.3 PSD and this morning I started it and it cranked fine then about an hour later I went to start it then it cranked once and ALL electronics died radio, lights, everything. So I mess around connecting and disconnecting the batteries then the interior lights came back on and I went to start it and it was almost like it was trying to start on one battery. The driver side battery is a week old and the passenger side one is old but still VERY good. Could it be the cables maybe? Bad ground? Any and all ideas are appreciated!!!
 

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I've been doing this stuff for a few years, so I should know better .. my first Ford was a '51 flathead V-8. Now I have a few, including a '99 F-350 7.3 CC LB 4x4. I've been fighting this "low crank" problem for a few sets of new batteries over the years, and I found a/the problem, out of desperation.

Take a high quality DVM, and measure the voltage between a battery terminal, and It's battery post .. NOT across the battery as you would expect. Across the battery post, and it's immediate terminal. Theoretically, you should read ZERO volts. I found 2.4xx volts on the passenger side positive terminal and couldn't believe my eyes. That's HUGE on a 12 volt system, and especially one that is needed to crank a 7.3 diesel when it's cold outside, and it gets cold enough to freeze the doors shut here.

So I judiciously shaved the terminal inside (Swiss army knife), and sanded the post with some 120, and cranked that mongo hunk of lead back on the post. Now she cranks right up like a new truck.

The DVM I used is a 22,000 count meter, costing about $70-$80 as I recall. Now you could probably get by with a H.D. $10-$15 meter, but you need to be a bit aggressive to make sure that the probe tips are broken through the thin lead oxide layer, into the actual virgin lead. Parasitic loads are always present, to allow enough current to get a voltage reading.

Do NOT have your buddie try to crank'r up while doing this, lest your meter becomes a fusible link.

You Do NOT need to disconnect either battery to do the above tests. With two batteries connected in parallel, they should measure exactly the same. Check all four connections. Cheers!
 

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I've been doing this stuff for a few years, so I should know better .. my first Ford was a '51 flathead V-8. Now I have a few, including a '99 F-350 7.3 CC LB 4x4. I've been fighting this "low crank" problem for a few sets of new batteries over the years, and I found a/the problem, out of desperation.

Take a high quality DVM, and measure the voltage between a battery terminal, and It's battery post .. NOT across the battery as you would expect. Across the battery post, and it's immediate terminal. Theoretically, you should read ZERO volts. I found 2.4xx volts on the passenger side positive terminal and couldn't believe my eyes. That's HUGE on a 12 volt system, and especially one that is needed to crank a 7.3 diesel when it's cold outside, and it gets cold enough to freeze the doors shut here.

So I judiciously shaved the terminal inside (Swiss army knife), and sanded the post with some 120, and cranked that mongo hunk of lead back on the post. Now she cranks right up like a new truck.

The DVM I used is a 22,000 count meter, costing about $70-$80 as I recall. Now you could probably get by with a H.D. $10-$15 meter, but you need to be a bit aggressive to make sure that the probe tips are broken through the thin lead oxide layer, into the actual virgin lead. Parasitic loads are always present, to allow enough current to get a voltage reading.

Do NOT have your buddie try to crank'r up while doing this, lest your meter becomes a fusible link.

You Do NOT need to disconnect either battery to do the above tests. With two batteries connected in parallel, they should measure exactly the same. Check all four connections. Cheers!
Nicec and concise tip. Really helpful I was suffering with the same
 

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2001 Ford F-350 4x4 Auto CC LB 7.3 3.73 axles 4” exhaust
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Sometime ago, had slow cranking, I knew the batteries were old. Came out of work hit key and just got a click out of it. Cleaned up connections as best I could with Jack knife. To my surprise it did start, but not the next day. I went out and bought 2 new batteries and cleaned connection. When I hit the key all I got was a click. Disconnected batteries, then went underneath to the starter and I could see Arc marks from the corroded connection. Took it apart replaced a nut and a washer and sanded contacts lightly. It’s been working good, but don’t overlook those connections when having issues.
 
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