Hey guys, first off I've looked at several different ford forums over the years and just have stumbled on yours, and from the different threads that I've read thus far, this group by far has a superior knowledge of the technical side of our trucks, not just "jump the starter and if that works there ya go" kind of answers.
Now on for my long winded very detailed question, I've got a stock '00 7.3, that has never liked cold starting, normally its a few minutes of cranking and romping and even recently 5 minutes of cranking before i can get anything after letting glow plugs warm up for over a minute.
After looking at your forum threads I've noted the ohms testing for the GPR and GPs at the valve cover connector and will be definitely looking into that this week when the weather breaks ( stupid rain ). and upon looking under my hood today for the first time in a while, I noticed a wire that was disconnected from one of the relays by the fuel filter... come to find out it was my intake air heater wire.. i have no idea why it would have been unhooked or if it has ever even been hooked up and I just haven't noticed. I did put it back on the appropriate post just waiting on truck to cool down enough from the days activities to see if it makes a difference. I have seen several people say that the pcm won't turn it on unless extreme cold I've been looking anywhere between 15 and 35 degree mornings where I'm at and my truck struggles hard. i don't always have the block heater on and sometimes even when i do it struggles.

what is the temp range for the intake air heater suppose to operate?
and assuming the glow plugs are good what if anything else should i look for?
i will be updating after the resistance and voltage checking, thanks again in advance for your answers!

 

To the best of my knowledge, the intake air heater only activates after the engine is already running, and even then the parameters for it to activate are pretty narrow. Apparently, it's sole purpose is to reduce smoke at idle, and has nothing to do with starting. I think you're on the right track checking the glow plug system first; it's the most likely cause of hard cold starts.

 

okay thats good to know, i have worked on some reefer units that have air heaters that kick on when the unit is about to start which i guess is why i figured it would be the same here

 

What weight oil are you running?

Mine starts a whole lot better with 5/40 full synthetic than 15/40 when its cold out. Another possible cause for hard cold starts is worn injectors. If switching to synthetic oil helps her light quicker in the winter, then that is a sign your injectors have sen better days.

 

On e way to see of the GPR is working is to cross the posts with a screw driver or pliers etc. Hold it there for about 20 seconds then get it and crank the engine. If it fires up then it's probably just the relay. I used to replace mine every other year it felt (I live in Idaho, so it gets cold). I found somebody on here that recommended an alternative to the parts house junk I was buying. I don't recall the name but it is twice as big and mounts on the side rather than vertically. Haven't had to replace one since.

 

stancor,i think is what you are referring too,thats one from Guzzle,Bob, at diesel o rings was the original poster of that,aand i have one and its great

 

i shall check and see on the gpr thing maybe tomorrow weather allowing, as for oil 289k miles and as far as i know its only ever had rotella 15w40 in it.

 

With almost 300k chances are you have a few bad glow plugs.
My truck wouldn't start under 50 degrees without being plugged in.
New glow plugs and it fires right up. 22 degrees no problem. (Lowest it's seen this winter)
5/40 synthetic will go a long way to help out cold starts also. Especially with those miles on the injectors.

 

"Stinky" has the GP system in 100% working order, 5/40 oil for winter, good batteries, and I deleted the whole Air Intake Heater. I have the same starts in any temperature my region throws at me, 100 miles from the Canadian border.

 

hey guys! sorry i took so long to get back been sick and foul weather here. finally got to look at it today and got the readings so heres what i got
.8=x x=.8
1 .=x x=1 .
1 .=x x=1 .
.8=x x=.8
Left side Right side thats the readings on my meter i got from the resistance test in the positions that i got it. i just feel like its weird its the 4 in the middle that show up bad? checked voltage coming out of gpr and it was at 11.7v

 

A reading between 1.0 ohms and 0.8 ohms looks good to me 0.2 ohms difference is nothing on a glow plug. Why are you looking at them as bad?

 

the two in the middle had a lot of space on it, like it was an open circuit there not actually reading 1ohm. thats my bad

 

It sounds like you're going in, if you're sure you're hitting the correct pins for GPs. GPs are the outer 4 pins. You might want to click on the UVCH link in my signature.

 

Yea I triple check cause I wanted to be sure, I'll check it out tonight when I get a few minutes thanks.