fed up!! truck wont start if it gets below 35 degrees

[stoken262]

i have an 01 7.3 and ive had a hard time getting it to start if i dont plug it in. ive replaced the gp relay and all the glow pugs and still wont effin start please help!!

[cbremodel]

I had the same problem. ended up that the starter didn't turn fast enough when it was cold. I put a new one on and now it starts without plugging it in.

[dieselburner21]

Might be your oil. Mine does the same thing but If your running 15w-40 thats probably it. But it doesnt bother me enough to switch to synthetic so I just have to love it

[stoken262]

the starter is brand new and also the batteries..........

[justinlogue5_0]

I just went through all this and NCHORNET helped me out. Just by replacing your GP relay and plugs doesn't actually mean they are working. You need to make sure your batteries are fully charged. Take a volt/ohm meter and test the volts coming from the other side of the relay making sure you are getting full 11 to 12 volts. If not replace relay with a stancor one. If thats all good now take a test light and make sure you are getting power to the gp wires. If you are looking down at the plug on your valve cover it will be the two end wire on each end of that plug. If you are not getting power check for bad/broke/wires and replace or repair. Next unplug the harnes and and check plug pins for burnt or corroded connections then ohm the plug on the valve cover side for resistence. Should be around 002 to 003. If you do not get this then your under the valve cover wires are bad or disconnected and you will need to check/replace them. And last but not least check your batteries. DO NOT USE a small battery tester. You need a tester that can put at least a 450 amp draw on a battery to test it. A bad battery in our truck will/can still be good enough to crank a gasser for another couple years. Here is a quick test for you to test your batteries your self. Take your volt meter and put it on your battery. Then turn your glow plugs on check your volts. Then with volt meter still on the battery crank the truck. If any where in this process your battery volts drop below 11 volts then your batteries are toast! Replace both of them at a time not just one. That motor has to spin over at atleast 250 rpm's before the pcm will notice and take over. Check all this and let us know what you find With all this working normal you shouldn't have to plug your truck in untill around -20.

[stoken262]

batteries are both brand new and good the only thing is when i turn my key on the big terminal on the drivers side of the gp relay doesnt get hot......

[justinlogue5_0]

Well then you just found why tour truck won't start. One large post should be hot all the time and the other side is hot when you turn the key. Either the new relay is a bad one or there is a wire issue with the little wires that come from the ignition to the relay that acts as a swith turning on the relay letting the power to cross to the other large post sending power to glow plugs etc...I can't look it up right now but maybe some one will chime in and tell you how to test those small wires.

[FordGuyPA]

If you place your volt meter across the two small terminals you should see 12v with the key on. If you do not see this 12v the relay will not energize. Now take you negative meter lead and connect it to ground if you see 12v on both small terminals, then the wire going to the PCM or the PCM is not telling the relay to energize.

[01clj]

I had the same problem and it ended up being the pcm was not provided a ground to the gpr so it wouldn't close to turn on the glow plugs so I wired in a momentary switch to cycle the gpr when i wanted and disconnected it from the pcm. Eventually my pcm went out and I replaced it then returned the wiring of the gpr to stock and it all works like it is supposed to. I quess what I am trying to say is it could be an issue with the pcm another symptom I had was the cruise control only worked intermitently and when I replaced the pcm that started working too. The pcm provides a ground to one of the little wires that go to the gpr.

[stoken262]

ok thanks guys i really appreciate it so does anyone kno what small wire is the ground?? and if i can just run an aux ground right to the battery??