I have a 2001 F350 turbo diesel and I replaced the glow plugs and glow plug relay but the truck still won't start in the cold after a few hours or if i don't plug it in at night it won't start!!!!

Does anyone have any ideas as into what it could be?

 

Interesting how all these cold start threads have started popping up. Check the strength of the batteries, they have to be in top notch condition in the cold. Make sure the GPR is working and turning on the GPs.
Then you can look in to switching to synthetic oil and see if that helps. After that I think you have to start looking at things like hpop and for leaky injectors, etc.

 

what is hpop

 

Welcome to FTE. HPOP is your High Pressure Oil Pump.

Let's start with the basics. Have you checked to make sure the new glow plugs and relay are working? There are 2 large posts on the GPR (relay) One is always hot. The other large post will only show voltage right after the key is turned on for up to two minutes. Remember just because you have new parts, does not mean they are working properly.

When you get it started, do you have any white smoke coming out of the tail pipe? If so, how much? How long has the cold start been going on? When was your last oil change?

 

yep they are working and there is no white smoke when i start it

I just did the oil change when i did the glowplugs and the GPR but it still wont't unless it is pluged in?

 

So if you don't plug it in, what happens exactly? Engine cranks a bunch and ...?

Any smoke out the tail pipe while cranking? Does the tach bounce? Oil pressure gauge start to show a reading after a few seconds? How long do you have to crank it before it finally starts without being plugged in, and how does it act when it finally starts?

How many seconds does your GPR stay on and how cold is it where you're at?

 

K the engine cranks a bunch!
no smoke out of the tail pipe while cranking and, the tach doesn't bounce but i never noticed it either, the oil gauge show s a reading after about 2 sec. I have to crank it a few times before it might catch or i have to either it a little. after the engine is running , after 2 min it will start missing and then blue smoke comes out and alot?

what you think new plugs and grp and it still does this, could it maybe be the fuel heater not harming up the diesel?

 

I was thinking that maybe the PCM is not sending a ground signal to activate the GPR so the glow plugs are not seeing any voltage, but if that is the case there should be some sign of smoke out the tail pipe while cranking. If you haven't checked the new GPR with a volt meter or test light, you really need to. It may not be the relay that's the issue, but a wiring issue that is not activating the relay. Another trick is to just hold a screwdriver across the 2 large posts for about 30 seconds before you try to start. If it fires up after that, your GPR is not working properly.

If you really don't have any smoke while cranking, and the tach does not move while cranking, then you've got some other issue.

 

when I tested the voltage at the relay it was 12.8 and with the key on it went down to 11.3 so that means it is working doesn't it, now after that i don't know, what do you think, come to think of it, i never really pay attention to the rpm and the oil so i don't know if they move or not but i really don't remember but i will try in the morning,

what about the blue smake after it starts, it only does it when the truck starts to idle down and it missfires, what do you think causes that?

 

I am also having the same problem . New Gp's and relay wired on a switch they work. And your also getting voltage. So maybe your not getting the fuel because of frozen water or gelled fuel in the tank or fuel filter or somewhere ??, thats what im looking at i may be wrong. When my glow plugs were bad i had smoke come out my tail pipe when it woudlnt start. Now i get no smoke like your saying and it cranks cranks cranks unless it starts then it smokes. My truck fuel pump was gurggling last week and there just was no fuel gettin to the pump on the frame rail. I had to pour diesel 911 and it cleared it up, although its 10 degrees now and it wont stay running once again and is missfireing at idle with blue smoke if it starts w/o block heater. So i guess the big question could be what does the cold kill in the fuel system? keep us updated i know im interested in a remedy.

 

Hey thanks for replying, well the truck is confusing me and givviing me a headache, when it starts if its not cold, i don't get it, the truck still won't start in the cold.

Puffs blue smoke and idles rough, what could be doing that?

Not Starting could it be losing fuel pressure or the fuel is gelling up in cold weather?

if anyone could help me please let me know and maybe something to try?

 

I had a problem with my truck not starting a while back .It would crank fine but would not catch. I had ONE bad battery. and I guess it was the passenger as that one feeds the GPR. Two mew batteries and never had another problem . And it would start if I plugged it in. Just a thought. A Curtis

 

I was going towards a bad battery! which one of the batteries provides the GPR?

 

Batteries are wired together but I think the passenger side goes to the GPR. Should replace both batteries at the same time. Also check all connections to ground. A Curtis