Hi, my 2003 7.3 f250 has trouble starting whenever the temperature is less than 65 degrees. If it is less than 50 degrees I have to plug it in for it to start. Once it starts it runs rough. I let it warm up and it still runs rough. Once I start down the road I'll get on it a bit and it takes off like something lets loose. It then runs geat for the rest of the day but does seem to still crank a little more than it should when I restart it through out the day.

The pickup has 152000k

List of repairs I have done to the truck:
-new gpr
-new glow plugs
-new uvch both sides
-new valve cover gaskets
-new blue cps
-new fuel filter
-new batteries everstart maxx 65n

The truck has an afe air intake, straight exhaust, and a super chips tuner set on mileage saving. It blows white smoke when first started but clears up pretty quick.

If anyone has any idea what could be causing this please let me know. Thanks

 

Bump...

I follow this forum a lot. Lots of great info for 7.3 owners. Hoping posting on here will answer some questions about my truck before I take it to the dealer and get ra**ed.

Any thoughts will be greatly appreciated.

 

Moved to 1999 - 2003 7.3L Power Stroke Diesel forum.

 

How many miles on the motor oil, and what kind of oil is it? If you program the truck back to stock, is the problem better, worse, or the same?

Did you do the repairs you listed above or pay someone else to do them? Reason I ask is, if you're game to pulling the valve covers, you can check to see if you have worn injectors that are causing this.

 

Thanks in advance for your insight. There's 2000 miles on the oil change. As soon as I bought the pickup I changed the oil and put in rotella 15-40 in after reviewing everyone's comments on here for good oil to use. I did all the repairs myself. When I had the valve covers off I ran the motor and unplugged each injector one at a time. They all made the motor miss when I unplugged each one. I also examined how they each spit out oil as it was running and didn't notice anything unusual.

I set the tuner back to stock and it made it run much worse. Rougher idling and not as much power. Figured that was because of the air intake and open exhaust.

I bought this pickup 3 months ago and should have done more research. The motor has excessive blow-by where when you flip the oil cap upside down it almost blows it off but i posted a video and got the response that it's not that bad.
It also burns oil. I already put a gallon in it since I changed the oil. And it has a real rich smelling exhaust.

It runs great once warm but has trouble starting and rough idle.

I also had to replace the pigtail wiring on the drivers side valve cover because the insulation around the wires was pealing off but it runs the same after I installed the new harness. (Knowing I have good connections and a legit install)

Just seems like ever commen flaw that these motors have, this one has it. Probably needs a overhaul but I'm trying to avoid that scenario.

 

So all the injectors are discharging oil when the engine is cold and the truck won't start? And the discharge amount is the same as when the truck has warmed up and running well?

Does the truck start any better if the ICP sensor is unplugged? Or the MAP sensor?

 

When I had the valve covers off it was pretty warm outside (75 or 80) so the truck would start and warm up pretty quick. Guess I should inspect the injectors when it's cold outside (55 degrees or so) and see what they are doing. Funny how 55 degrees is cold to these engines or at least this one.

I'll try unplugging those sensors and see how it runs.

 

When I let the truck warm up then start down the road it runs rough until I get on it a bit. Then it snaps out of it and runs good.

Would this be whatever the flapper under the turbo is that helps the motor warm up faster? Not sure what it's called but seems I read something about it.

 

That's your exhaust back pressure valve (EBPV). If that were activated the exhaust would have that jet engine sound to it, but it wouldn't affect how the truck ran.

 

Ya I notice you can't even hear the turbo until you get on it.

But I just went to start it after it's been sitting for a few days. It's 64 degrees and it had a he** of a time to get started. Then it shuck like crazy. Now it's warm and just all of a sudden picks up and idles smooth like a switch was flipped.

I unplugged the icp as I was trying to start it and it still just cranked and coughed.

 

Looking back to the last things that I have changed on the truck is that I filled up with diesel at a different station than I have been. And also I replaced the cps because the old grey one was causing the truck to miss at highway speeds.

 

Just thought I'd update this with my solution. F350-6 was right about the icp sensor. I messed with it some more and noticed when I unplugged it there was no change in the rough idle. There was also oil on the pigtail. So I replaced the sensor and it solved the no start in 60 and below weather problem and also idles much smoother.
Thanks for your help.

 

Super! Congrats and big thanks to F350-6 for the fix.

Now for the oil usage. Have you changed your fuel filter? If so, was it black?

 

No I checked the fuel and it appears to be clear in the fuel bowl.