cold start problems 03 7.3
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Joined: Feb 2007
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cold start problems 03 7.3
I have a 2003 f-250 7.3 diesel, up to this year I have had no problems with cold starting when the truck is not plugged in, as of this year I have been having problems with cold starting I have heard horror stories of very costly fixes at the dealership can anyone help or direct me on where to start to diagnose the problem myself.
uarep
uarep
Last edited by uarep; Feb 16, 2007 at 12:19 PM. Reason: spelling
Post Fiend
Joined: Jun 2004
Posts: 9,293
Likes: 10
From: Parker, CO
Most common culprit is the glow plug relay. It sits on top of the engine over the passenger's side valve cover. There are two relays, the one in front is the AIH relay, and the one immediately behind is the one for the glow plugs.
You can test the output of the relay with a multimeter. You should see 11+ volts on both large terminals with the key in the run position. That means you are getting power in and power out.
If you don't have a multimeter handy, take a screwdriver and with the key on, jumper the 2 large posts. You'll see a spark, don't worry. Hold that screwdriver there for about 30 seconds or so, then crank the truck. If it starts up without a problem, then you know that the relay is bad.
P.S. Do this when the engine is cold, so you get an accurate test.
You can pick up a replacement for cheap at Napa, about $25.
You can test the output of the relay with a multimeter. You should see 11+ volts on both large terminals with the key in the run position. That means you are getting power in and power out.
If you don't have a multimeter handy, take a screwdriver and with the key on, jumper the 2 large posts. You'll see a spark, don't worry. Hold that screwdriver there for about 30 seconds or so, then crank the truck. If it starts up without a problem, then you know that the relay is bad.
P.S. Do this when the engine is cold, so you get an accurate test.
You can pick up a replacement for cheap at Napa, about $25.
Freshman User
Joined: Oct 2006
Posts: 44
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From: Twin Falls, Idaho
Go to the very first post in this 1999-2003 7.3L PSD section for common mods/maintenance.
There is some excellent stuff to help you out with cold starting/ hard starting and what not. Good luck!
There is some excellent stuff to help you out with cold starting/ hard starting and what not. Good luck!
Laughing Gas
Joined: Feb 2006
Posts: 947
Likes: 1
I also have a 03 and live in wisconsin and work nights with no power to plug in. This year i changed out the glow plugs, you can ohm them out with a multimeter from the valve cover harness and a couple of mine were bad so i replaced them all. Pretty easy job and only about 8 bucks a peice at autozone, get the motorcraft brand cause there have been some problems with the tips breaking off with the other brands. I also replaced the glow plug relay just so i knew it was new and working, I got mine from www.discountfordpartsaty2k.com for under 60 bucks shipped, it was a oem motorcraft. Guzzle used a big one, you can do a search and read about that. I also put new batteries in, got them from walmart for about 60 a peice, read good stuff about them and they have a good warrenty. I also switched to 5w40 rotella synthetic(16 bucks a gallon at walmart, cheapest place to get it) with the light oil it starts alot better.
Postmaster
Joined: Jan 2004
Posts: 4,758
Likes: 7
From: colorado
read through this, everything you need to know about clod start problems: https://www.ford-trucks.com/forums/4...ke-thread.html
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