3 weeks ago i bought a 2002 f350 with a 7.3. two different times after a short drive when i try to start it the starter turns over fine but it will not fire. the first time i let it set for 45 minutes and it started fine. the next time i tried it after about 5 minutes and it started any help would be great. this is my first diesel so i am lost. thanks Todd
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clean all battery post really good..load test both batts while they are un hooked...these thing will crank all day long like the batts are strong..but if you dont have at laest 10.5 when cranking..she will never fire...

 

If Ron is right and the batts are the problem.Change both of them,not just one.

 

thanks i will start with them

 

well i cleaned all the posts and some other connections that were crusty looking.then had the batteries tested an was told they were fine. under a heavy draw down test one was 9.4 and the other was 9.5.the truck has been fine for a month. then today no start after a short trip.then 10 minutes later it was fine is 9.4 and 9.5 on a draw down too low? thanks Todd

 

You need to test them while they are tied together. You can NOT drop below 10.5 on start or the IDM will not have enough voltage or current to generate the 1.1 Gigawatts.... Oh oops, to much Back to the Future, I mean 110v to 140v to fire the injectors and let fuel into the cylinders to start the engine.