One more thing, Dwenter, I have a similar truck to yours, a 1999.5 F-550 and it stranded me in a campsite one morning while on vacation in Colorado.
It was a simple fix, I changed the glow plug relay and then disabled computer control of the same relay. I installed a button on the dashboard that turns the relay on and off. I have to hold it on for it to remain on.
It's the best way to run the glow plugs IMO because you know when they are on and when they are off. You only need them to get the engine started anyway, then the compression ignition of the diesel engine takes over from there and you don't have to do anything more for the rest of the trip.
If it's above 60 degrees outside, I don't even bother pushing the button.
Below 50 it won't start without a 10 count pushing the button.
Below freezing requires 30 seconds for the engine to start without spluttering.
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The engine will blow a lot of white smoke out of the tailpipe first thing unless you sit there and hold the button down for a couple of minutes after the engine starts.
I just drive away and it clears within seconds.
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It's easy to install the button. There are four wires going to the relay, two large and two small. The small wire on the driver's side is the one that you want to disconnect, wrap that one with some electrical tape and zip tie out of the way.
Now run a wire from that post to the cab, through a pushbutton switch that you must hold down for it to remain on. They call it a momentary on type of switch. Run the circuit from the glow plug relay through that switch and from there to ground.
That's all you need to convert the glow plug system to full manual control.
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I took it one step farther, but it's not necessary. On the passenger side of the relay, there is a large red wire and a smaller black? wire right next to it. The big wire has power all the time to that post whether the key is on or not.
The smaller wire is switched, it won't get 12v until you turn on the ignition key.
What I wanted was to be able to heat the glow plugs before I turned on the key so I made a little jumper wire that goes from the big post to the small post. It's no danger in doing that because the relay won't work until you push the button in the dash and complete the circuit.
I've had it that way for more than a year now and have no plans to return it to the way it was, it just works so much better than relying on the computer to know how long to heat the glow plugs.
Hope this helps.

 

Good posts Dan!!!

 

Thank you...............

 

Yes ...mainly ....

 

Thanks, Rick.
Now if Dwenter will just make it back here, I hope she didn't get scared off by the earlier remarks.

 

I'm back, I don't scare too easy I married a caveman!
Any how I will check into the manual GP switch. Also do you all happen to know if using the manual GP switch is very helpful with cold starts when unable to be plugged in? I have a construction company and so I travel all over and can not always plug in motels frown on such needs. I just need a chance to get back to the ford.( work and things) like I said my husband is a caveman so his mechanical abilities are not. Remember this is my spouse not men in general.

 

I would guess if you go the GP switch, when its cold out, you just hold it longer to start. If you have a healthy GPR it will start when cold with out being pluged in.

 

Get a heavy jumper cable and go straight from a positive batt terminal to the GP side of the GPR. Hook this up and time it. Say walk around and get in the truck. At about 60-90 seconds, turn the key to WTS for about 5 seconds, crank the truck and see if there is a difference. Oh, go out and disconnect the cable straight away as the GPs will stay on.

If it starts fine, your GPR is done. If no difference, the GPs may be done.

Sorry I have not read all the thread but I am jamming through them tonight. If this has been covered or not your problem, good luck.

 

I'll quote Mike's statement as the best way to verify the condition of the glow plugs/relay system. If you do decide to convert over to manual, then all you have to remember is the colder it is outside the longer you have to hold the button down. I've never had to go beyond 15 seconds to get the engine to fire, but I live at sea level in Seattle where it's extremely rare for the temperature to get below 20 F in the dead of winter. High altitude Colorado or some place like that would take a lot more.
As time goes by you'll get the hang of it, the truck will let you know.
Usually all it takes for me to get it fired is 5 seconds with frost on the window, but it makes a lot of white smoke, so I give it 10, hit the starter and hold the button down for another 10 after it catches.



Before you convert it over I would verify that the oil temperature sensor is good.

 

OK, I went and looked it up.
The baro meter is part of the ECU so if it turns out to be bad, then you have to replace the entire control unit.

The glow plug system is electronically controlled by the powertrain control module. If the temperature is below 131 F the powertrain control module will energize the glow plugs immediately after the key is placed in the ON position. Then, depending on the readings from the engine oil temperature (EOT) sensor and the barometric pressure (BARO) sensor, the powertrain control module determines how long the glow plugs will be on.