HELP!!!01 Won't start if not plugged in.

[CHAD5.0]

I have checked glow plug system and it is working, even replaced glow plugs just to be sure. Air temp does not matter, if the truck is not plugged in it will not start. I hooked up OTC scanner and did a injector buzz test and they all passed. Cranking RPM on the scanner is 140 RPM, IPR duty is at 35%, and ICP is showing 2200 PSI ( not sure why it shows so high). This truck has 450,000 miles on it and I am leaning towards low compression being the problem but just wanted some other input from you guys. Any help or ideas would be appreciated. Thanks, Chad.

[ridgerunner98570]

Most likely the glow plug controller/solenoid . They go out about every couple of years and yours has probably been out through the summer, but when the outside air temp is warm, the truck will start and when the cooler weather hit, it wouldn't. Go to power stroke's search the forum, and type in glow plug relay. It's an easy swap right on top of the engine. Here is a link to the article that tells you how to check it your self.

Troubleshooting GPR & GP's

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Last edited by ridgerunner98570 : 11-05-2009 at 08:16 AM.

[CHAD5.0]

The glow plug system is working. Outside air temp does not matter, it will not start if not plugged in to keep engine temp up.

[md18]

I there any smoke while cranking?

[CHAD5.0]

Originally Posted by md18

I there any smoke while cranking?

Nope. It does fire once in a while then it smokes, but it will not start.

[Bear1971]

I don't know enough about them to guess, but this website really helped me out: POWERSTROKEHELP.COM - The Information Source for Ford Power Stroke Diesel Owners

[ridgerunner98570]

Sounds like it may possibly be a fuel delivery problem. It makes not 1 iota of sense that it will start if the engine is plugged in and the glow plugs are all working, but won't start if it isn't plugged in. Did you check the relay? My glow plugs were all good when mine did the same thing but my relay was not putting enough juice through it to cause the plugs to get hot enough to work. Recheck the voltage on the relay and then check the voltage to the plugs at the harness. Plus try cycling the glow plugs 5 times and see if it then fires.

When you have it plugged in and it starts, how long does it turn over before she cranks? And you have of course drained the water out of your filter if you are in a cold area right?