sorry for so long sence my last post. i have trippl checked everything in the gpsystum everything is functioning perfectly. if i leave the truck for 5-6 hours in 20 degree weather it wil start but skip real bad until it warms up. it acts like it has a couple loaded cylinders, im thinking that i have some bad injector o rings that when they get cold contract and leak by filling the cylinders with oil, my next test rrior to changing the o rings is a compression chec but the truck has tons of balls so it really seems un likely. do the injector o rings make sence? i have delt with a lot of 7.3s but have never come across this problme...

MINE was the short relay selonoid on the top of the motor thanks for the help

You will not get oil into the cylinders with bad o rings...

How many miles on the truck?

my2000 f250 does the same thing. it will not crank unless you have it plugged up over night. but how can a relay cause the problem when it is cold? seems like to me if a relay is bad the truck shouldnt crank no matter what the temp is, my truck only has 150k on it.

might be glow plugs

I have been having the same problems my truck has good compression and new gp and harness as well as relays and even new injectors but still have same exact symptoms as the first post but I also noticed my truck also do not have the factory cold high idle but the ebb valve does work I think it may me a sensor or something that doesn't tell computer it is cold

with the glow plug relay out it will start in warm weather as you do not need them but in cold weather you do hence the no start. plugging in the block heater would make it start. just to be clear i'm only explaining this to him i'm not suggesting something you have said so many times. now are you getting any codes?

Mine will start with reg oil, but much much easier with synthetic oil. Take some 15w 40 and some 5w 40 leave it out over night and see which flows faster. Then you know why the truck chugs when cold if you run 15 40. Mine would crank slow and romp when I had 146 40 in it even if it was 30 degrees. Then I went back to synthetic. I can start it at 0 degrees not plugged in and its just fine. This could help your romps, but has no effect on a no crank, thats another problem

Living in Orlando, Fla. I do not have the 20 degree weather, but I do still ahve the warm up issue. 2003 7.3 236k. Runs and starts just fine the rest of the day. First start in the A.M. is always rough. Like it is only running on 6 cyl. Smooths right out after the engine warms up. Always have given it 10 minuntes in the driveway before going down the highway. "short solonoid"? Is this near the fuel bowl where the 2 solonoids are mounted. One is taller than the other. So you changed out the short one and this fixed your problem?

Glow plug realy