2003 7.3 Will not start
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2003 7.3 Will not start
My '03 F550 started missing on my way home. The truck slowed to 25mph. The engine light came on. I was only half a mile from home so managed to get into my driveway. Fault codes showed, "low system voltage", "low boost pressure" and "Fuel relay code fault". I checked the fuses and replaced the IDM relay to no avail. I checked the filter/water separator no prblem there, and I am getting fuel pressure up to the filter. I have not been able to start my truck since I pulled into my driveway. (the cam sensor was changed four years ago). Can anyone out there give me any ideas of where to check next?
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I used a SuperChip Modifier/code reader to pull the codes. It isn't pushing out any smoke at all while it tries to start and the oil, (Amsoil), is just fine both quality and quantity, no sign of any contamination. The cam sensor was already changed and that was picked up by my same code reader when it happened four years ago. That code didn't show up this time.
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Joined: Sep 2004
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From: Weimar,TX
Denis K,
Welcome to FTE! Sorry you're having problems with your 7.3.
I would scroll down to the 7.3 forum and let them have a shot at your problem
Some very knowledgeable guys and girls and they are always willing to help.
Good luck
Welcome to FTE! Sorry you're having problems with your 7.3.
I would scroll down to the 7.3 forum and let them have a shot at your problem
Some very knowledgeable guys and girls and they are always willing to help.
Good luck
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Joined: Jul 2002
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From: Long Island USA
Thread moved to the 7.3 forum 
With the "low system voltage" I'd check the batteries and the alternator before going any further. Like John said, it might crank, but not have enough voltage left over to fire.
But then, the "low system voltage" might have come up while trying to start it
With the "low system voltage" I'd check the batteries and the alternator before going any further. Like John said, it might crank, but not have enough voltage left over to fire.
But then, the "low system voltage" might have come up while trying to start it
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Both batteries were new last summer and showing great results. Tested each of the two alternators seperately both kick out up to 13.9 volts depending on load induced. One friend suggested check out the PCM. If this is the problem, can it be reflashed?
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Joined: Jul 2003
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From: Newport, WA
Yes it can be reflashed by the dealer, or possibly by DP Tuner (cheaper and better, IMO).
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My 2003 seems to avoid keeping the appropriate components in the place suggested by Ford. The PCM was supposed to be under the hood but it is in the cab on the driver's side kick plate. The "under hood fuse block" doesn't exist. The FICM is actually an IDM - by the way, where should I look for the IDM??
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The IDM checked out OK so I finally broke down and had my F550 hauled in to the local dealer. It was the left bank UVCH. I thought that the engine would have fired up anyway but no dice. The part, a little plastic wedge, was $21, the cost, (including tow), $576. Getting to haul *** in my F550 once again........priceless!!
Thanks to everyone for your advice, my next purchase will be a decent code reader, any suggestions......?
Thanks to everyone for your advice, my next purchase will be a decent code reader, any suggestions......?
