Mods I hope this is ok to post. There are some links here to a site related to diesel enging repair and mods.
This is all info I found searching the web when my truck had problems in the cold. I hope it can help you guys out, it saved me a bunch of money.
This if for the 7.3 Powerstroke engine but they have stuff for all engines there
Cold Sart / No Start problems in the winter. Here is what you should do first.
1. New fuel filter
2. New air filter
3. load test batteries, even if the engin cranks check the batteries
4. New oil and filter, you can even run a 5w40 in the winter as long as ouside temp doesn't get above 80 deg. ( I didn't I just put 10w40 in because I have a couple of 55 gal drums I picked up at an auction.)
If all of this doesn't fix your problem here is how to check out the glow plug relay and the glow plugs.
How to check Glow Plug System by Klhansen Eagle River, Alaska (
TheDieselStop.Com)
To check the Glow Plug Relay (GPR)
· Be sure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won't have as much time to check.
· Locate the GPR - Its behind the fuel filter on top of the engine, a little bit toward the passenger side of the valley. There may be two relays there. If so, the rear one is the GPR. It will have two fairly large wires (yellow and brown) connected to one of the large posts.
· With your multitmeter set to DC volts, and 15 V range (if not autoranging), clip the positive (red) lead to the output terminal (with yellow and brown wires connected), and the negative (black) lead to a good ground point (like the battery ground terminal or someplace metal directly on the engine block.)
· Turn the key to ON (do not start)
· If your GPR is good, it should click, and you'll see 11 volts or so on your meter, then, depending on temperature, it will click off up to 2 minutes later. You should do this a couple of times to make sure it consistently makes the connection.
· If you don't get voltage with this test, confirm by retesting as follows.
· Remove the two small wires from the smaller two of the four GPR terminals.
· With jumper wires, apply voltage from the battery across the two small terminals.If your voltmeter now reads voltage on the output terminal, your GPR is OK, and your problem is in the PCM circuit that tells the GPR to activate.
To check Glow Plugs.
· Remove the electrical connector on the inboard side of valve cover at the gasket. Press down on the top of the connector latch and pry gently with a screwdriver.
· There will be 9 pins on the valve cover gasket where you removed the connector. The two pins furthest forward and the two pins furthest back are for your glow plugs.
· With your multimeter set to resistance (ohms) and low range (single digits) if not autoranging, clip the negative (black) lead to a good ground point.
· Probe each of the 4 outer pins individually with the positive (red) lead, noting the resistance. Good glow plugs will have a resistance between 0.6 and 2 ohms. If you get infinite resistance on any glow plug, that one is either bad or the connector under the valve cover has come loose.
Here is the link to a pdf file of the directions along with illustrations. It's from the same site but another poster from NV.
http://www.streamload.com/nlemerise/Ford/gpr.pdf
I hope this can help others out, I know it helped me. I love that site as much as I do this one. There is a lot of great info there.
Pat