03 7.3 Rough Cold Start
 

Got one of the last 7.3's they made, extremely rough cold start, also misses in one cylinder.
Is it glow plugs?
I dont know about diesels, but in a gasser this would be intake gaskets. Are these a common go-out item?

Intake air heater might be having issues as well as glow plugs. It might be a combination of the 2. your valve cover gasket is unique it allows connections on it. you might want to start by checking those connections. Big possibility that those might be bad or not connected properly. check those if it is not them let us know.

allright. I dont have the truck yet, but its an 03 extended cab utility body diesel 6speed with 200,000. Guy only wants 3500 bucks! Just wanted to check and make sure it wouldnt be like a 10,000 dollar fix

Naw Glowplugs and valve cover gaskets are not hard and not that expensive.

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I missed the part in your post that I just bolded and highlighted. You might want to get the checked for compression in that cylinder, and possibly checking the ECM for Codes. It might be possible that either an injector or a piston ring failure. Never hurts to have these things looked at by a local shop that you can trust before you spend the cash.

More then likely its the Glow Plug Relay.

With a test light and the key off, check both big terminals. One side should have power and the other should not.

Now turn the key on and check. Both sides should have power for about one minute to one minute 30 seconds...

If not, then replace your relay.

There are two relays there, the one closest to the turbo is the GPR, the other is for the Intake Air Heater...


The Intake Air Heater has nothing to do with cold starts, it is only used for extended idle conditions to help stop white smoke complaints. It does not even turn on unless the oil temp is above a preset level (notice I said ABOVE). It also will not turn on unless the truck is in park with the brake set...

IE, it never comes on.

With 200k on it, it more then likely has several issues, Glow Plugs, Glow Plug Relay, And possable UVC (Under Valve Cover ) harness issues...

Need to get it scanned, but check the glow plug relay first off.

Once Warm, does it smooth out and run fine? If not, remove the oil fill cap and flip it upside down. Set it back on top of the filler neck. It should not blow off, it will move around, but should not blow off.

That explains why there is a delete for that. Thanks Joe.

Sorry I never posted back to this, a lot has been going on since then. Anyway I never got the truck, the guy had already sold it when I called him. However, last weekend I got the greatest deal known to man. It's a '99 f350 dually service bed 6 speed and the 7.3. All it needs is the cam position sensor. Got it for (if you beleive me) 1500 bucks!:tu:

Awesome! That's a heck of a deal!

It was just too good to pass up. I'll be 15 soon so I won't need it for another year, but it is gonna be getting built up. And before you ask, this isn't my daddy's truck. This is one that I am going to be paying for. Any suggestions for the first mods? (it is getting a flatbed)