I have a 01 7.3 crew cab dually and it's had cold start problems since i got it in 09.I have replaced everything i could think of including glow plugs gpr,harness and batteries.Any temp below 40 i have to plug it in .If i cycle it 3 or 4 times it will start but it smokes and runs ruff. My 00 7.3 excursion starts up down to about 10 degrees than i have to plug it in so i know dually is not right.I have a afe intake,1.5 injectors,driven diesel rr,adrenilin pump,dp tune by gear head.Kinda at wits end don,t mind pluging it in in dead of winter but now one night it's 30 next it's50 and i don't have to . Also have fully built trans by level 10 if it matters .I get battery light coming on every now and again.New alt about every year and a half.I have read lots of threads about it and i just can't figure it out .My mechanic says everything works fine.Obiviously not a diesel specialist.Any help would be greatly apreacited.

 

Oil is key in the winter. What is your oil?

 

Did you check for burnt pins on the harness or the 9 pin connector? Also what Tugly said, what weight oil?

 

An alternator every year and a half? Sounds familiar....

https://www.ford-trucks.com/forums/1...l#post15717024

https://www.ford-trucks.com/forums/1...l#post15729502

You need to thoroughly check all the components in your charging/ground circuit. The threads above covers a lot of that. I have no more problems on my 01 with alternators burning up (I hope).

 

Sounds like your new relay is know good. If you hear it click to soon it bad.

 

thanks for all replies.Oil is rotella 15/40.Harness in valve cover is new.Is there away to check power to harness?Realy buzzes for 2minutes which is when i try to start.

 

Synthetic oil is best. Some use 5w-40, others 15w-40. Not real particular about brand, just make sure diesel rated.

What glow plugs are in it?

I would also try crossing the terminals on the GPR with a screwdriver or wrench for a minute then try starting it. Just because it buzzes doesn't necessarily mean it's working.

Burning up alternators like that, you have a serious electrical problem. It may be that whatever is destroying your alternators is drawing your batteries down too much for it to start properly.

Check ground wires. All of them, not just the negative leads off the batteries.

 

Your GPR buzzes?

Usually when you hear a relay buzz it is "chattering". chattering means there is a problem with the relay or the energizing circuit and it it not making good contact.

 

Take a gander at that there video. Some things to consider on cold starts with older injectors, and a great explanation of how computer/IDM works.

 

When i fist got truck i ran amsoil synthetic all the time but the 220$ oil changes where killing me.Made no difference in the way it started run rotella in ex and that starts after short pre heat down to 10 degrees. What i notice about ex is when it starts it goes into highrpm idle right away.. Dualy kinda starts at lower rpm and raises rpms gradualy.Got glow plugs when i got new injectors about a year ago from full force they are motorcraft was hopping after spending 6,000.00 on truck it would have started better but nope.Checked all grounds around and under truck all look good.The truck spent most of its life in florida i just think its spoiled and doesent like cold.When i change relay i checked voltage and got 12v in and 10v out.What is the cheapest way to do buzz test and other engine test the gauge or scan tool or something else .? I hate computers.My brain is in stone age carbs pull out chokes 3 on the tree more wires more to go wrong.

 

That's not right. What ever your battery is at you should have in and out at the relay or very very close to it but not 2v difference.

 

Have you checked the HPOP reservoir? Is it full when you go to start?

How does the truck run once warmed up?

 

MAYBE YOUR STARTER IS BAD. NOT CRANKING FAST ENOUGH..

 

Yes, 2 volt drop is no bueno.

Put your leads across the relay (one lead on each post) it should read close to 0 when ON and near batt voltage when off.
What voltage you are reading (ON) is the amount of current NOT flowing to the glow plugs.

 

Have a brand new not rebuilt starter the good one that spins fast.Had the slow spinning starter though that would cure my problems but naaaaa!Willcheck hpop and relay today .THe Hpop is brand new adrenilin done with injectors and rr.Thanks for replies.