So I recently bought a 95 ford f250 7.3 and on my way home it kept shutting off after so many miles once it cooled it would fire back long story short I eventually found a nut seized in the top of the piston and the diesel shop said it cracked the block. So I bought another truck from a guy at work a 97 f250 7.3 I got the engine swapped and it fired right up we let it idle for a while and shut it down started it back up let it idle some more and took it down the road after about a 1/4 of a mile if that it was like a switch flipped and it started idleing rough and and lost all of its power and the check engine light came on I had to keep giving it fuel so it wouldn't shut off and I had the peddle to the floor just to get it back to the garage and two brand new batteries were dead . Today we put new batteries in went to start it and it sounds like it should at first and then sounds like it's starving for fuel .. it will only start if you hold the peddle but then it idles rough and it drained another set of batteries I put a new alternator on but didn't help. Any help is greatly appreciated this is my first diesel and my first thread

 

- check fuel pressure manually to see if you have proper pressure.
- the rough running issue sounds a lot like a UVCH issue. Google "7.3 UVCH" and read up.
- OBS trucks will not send a signal to the alternator telling it to charge if the little battery light on your dashboard doesn't illuminate. Check to make sure you have that light on the dash when you cycle the ignition. If it's burnt out your alternator will never charge.

 

I'll check UVCH out I do have the little battery light come on when I cycle the ignition

 

Sounds like something was shorting out to kill two new batteries!

 

Check the glow plug relay to see if it is working properly. It is located at about the 9 o clock position, in the center of the engine, near the passenger side head. It looks like the fender mounted starter relay. With the key in the off position, there should be power to one large post, the other large post should be dead. When the key is placed in the run position, the relay should energize the other large post, for up to 2 minutes, depending on temps. You can use a test light, or better yet is a multi meter. If the relay is stuck on it will drain the batteries in short order.

 

Thank you farmert I will try that on Monday and let you know how it goes ... would that be the reason why sometimes I go to shut the truck off and the lights stay on. Lights on the dash the tuner .. it dosent do that every time just one in a while and you have to take the terminals off the battery

 

Mine does that once in awhile, I have restart the motor and push and pull the headlight switch.

 

Ok so I checked the glow plug relay today and with the key in the off position I had power to one large post then with the key in the run position I still only had power to one post