Hi all... ok, here's the bottom line:
1993 F-350 7.3 non-turbo
Start up, it blows a lot of smoke. Mostly white. It takes a minute of cranking on it before it will fire up if it has been sitting a day or two. If I cycle the glow plugs 3 times it seems to start a lot easier. Once it is started it will run real rough unless I turn it off and start it again (most of the time it will idle smooth, but smoke real bad). I have this problem when it is cold or warm. It makes no difference. When I am running down the road, if I have my foot in it all the way to the floor it doesn't smoke and runs just fine. Lots of power. When I let off and give it just enough to keep a constant speed, it smokes real bad and jumps a bit (almost like a bad miss in a gas engine). So, it is fine with either all or nothin.
I have the same problems if I run the truck for a couple of hours and then turn it off for ten minutes, except it will start right up without having to crank on it for a minute.
I have changed the fuel filter, filled the new one up with Howes diesel treatment. I run Howes in my Freightliner and I figured it wouldn't hurt to try it in my F350. It didn't make a bit of difference...
I don't know that much about little diesels and need a little bit of help on this. My first thought is the injector pump, but I don't know how to test this one to figure out if it is what is causing the smoke or not.
I was going to replace it to find out if that is the problem, but when I couldn't find one locally for less than $525 exchange, I have decided to trouble shoot it a little more.
Any help on the trouble shooting would be most appreciated.

Thanks!

 

most likely your injectors are dripping fuel...........clean and set them...then set the timing.............
crossbones

 

Change your fuel filter, and use diesel kleen or some other additive with injector cleaner. I used 2 bottles in one tank, as well as changed my filter and she runs right now. Had the same problem and couldnt figure it out. I added the diesel kleen and changed the filter, works fine now

 

Alright, I will change the filter one more time and use diesel kleen this time both in the tank and the filter.
--Crossbones, how do I set the timing on a diesel?? I always thought that was done thru the injector pump and couldn't really screw it up. Is there another way to do it?? I know how to remove and clean the injectors... in which case I will change the o-rings before they go back in.

 

You can use a diesel timing light to get it in the ball park..........you may have interest in the thread "Using your glow plugs to super tune the engine"
crossbones

 

I read the thread... however, I still haven't figured out the whole timing thing with the diesel. I am thinking it is about time to go and buy a shop manual on this one. I can do just about anything with a gas motor or a big diesel... but shockingly enough there is a world of difference between the 12.7 liter detroit that I have in my semi and the 7.3 international I have in my F-350. I am still learning on the small diesels. So please forgive my ignorance when I ask for detailed instructions on the procedures in the process of trouble shooting this thing. I have never seen a diesel timing light, I am going to the parts houses to see about getting one now.

 

white smoke means air intrusion, so why not replace return lines and o rings. inspect the steel fuel lines.

 

I will try replacing the o-rings and return lines.... I tried putting the diesel treatment in the filter and loading up on it in the tank. That has made it run a lot smoother but, it still smokes a little bit and now at about 2000 rpm it is blowing blue/black smoke. The motor has 131k on it... so I am guessing the rings are shot. It doesn't use much oil between oil changes... less than a quart in 5000k miles.

 

do you have a clean airfilter and have cleaned the cdr valve looks like a can on the back of the intake pull it off an wash out with gas let air dry do not blow dry [will harm it] been there done that this serves the same purpose as a rdf tube on the big rigs

luck to ya

 

I am leaning towards air intrusion as well. It is like drinking soda with a crack in the straw. The IP can't build the right pressure to pop the injectors and when it does it is off time because it has to compress the air first. The fuel return lines and "O" rings are big culprits for air intrusion. Check for wetness around the injectors make sure everything is tight. If it is original time to get a replacement kit. When your driving at highway speed the amount of fuel being moved by the lift pump is over coming the air so the diesel will run just fine.

 

AIR. Do the return lines and eliminate the return line from the filter head(next to schrader valve) down to the #1 injector. Start with that and let's see what you get.

 

If timing is your issue and you don't have the correct equipment to set the timing with a light, here is how you can set your timing "by ear". First off there are 3 nuts that secure the IP to the gear housing. Adusting the timing requires loosening these 3 nuts and turning the IP. If you move the top of the IP towards the passenger side it will advance the timing. Moving it towards the driver's side will retard the timing. If timing is your problem, then the symptoms (running rough and smoking) indicates that the timing is too slow and needs to be advanced.

A warning; DO NOT attempt to adjust the pump timing with the engine running like you would with the distributor on a gasser. Make sure the engine is off before loosening the adjustment nuts, and make sure that at least 2 of the 3 nuts are tight before restarting the engine. I've heard people say that they have adjust theirs with the engine running but every instruction sheet or manual I've seen says that you can damage the pump that way.

The other recommendation I'd make is to not stop advancing the timing just because the smoke clears up. Instead keep advancing it until you just start to hear a bit of a "powerstroke rattle" when accelerating. It sounds a lot like spark knock or "pinging" in a gasoline engine (because that is basically what it is). Once you reach that point, then back it off to the last previous adjustment setting before it started rattling and tighten the 3 adjustment nuts to lock it down.

When you're doing the adjustments, be sure the engine is warmed up to normal temp, and for good measure disconnect the cold start timing advance. Once you get it all adjusted reconnect the cold start timing advance and let it cool down. When you restart it the first time after it has completely cooled off you'll notice that the "powerstroke rattle" is back, but that's what you want. Once it warms up and the cold start advance kicks off the rattle will go away.