I just bought a 87 f250 with a non turbo 6.9L.
I have read alot in the last couple weeks.
The smoke I'm getting is a gray white color.
What will cause this?
I was thinking the last owner tuned up the fuel to try to get more power.
I was thinking of turning the fuel down alittle and see.
Or will this cause a lean condision?
Does anyone know the factory setting for the pump?
I'm new to the diesel engine.
I have already cut out the soupbowl, changed out the stock muffler and changed out the injector orings.
Next is pulling the tanks and fixing the pickups so I can use the other 18 gallons.
Thanks
Steve

 

i take it the gray white smoke is under a load or getting on it to pass?usally to much fuel is black smoke.thses are mechanical injection engines,so a little smoke under accellaration is normal.you cannot run a diesel lean.

 

Are you just getting this smoke at start up or all the time? A little more info would make it easier to give a good guess.

Milage on the engine and outside temps and engine temps as well as idle, running easy or standing on it up a hill.

 

Very rarely is smoke in a Diesel caused by the injection pump. If someone set the pump too high (too much fuel) the engine will only smoke when you have your foot buried in it and there is a big load(pulling a hill). Smoke is usually an injector problem. If the injectors aren't atomizing the fuel correctly you will get light grey to white smoke depending on who is looking at the smoke. Pump timing can also cause smoke but usually when you get the timing out far enough to smoke you will have other problems .

 

Thanks guys
It smokes alittle all the time even at idle.

mechanic-I think you got it. thats what it looks like.
So it looks like its time for injectors.
Could this hurt preformance and milage?
I don't have the cash to replace them right now is it ok to drive it like this?
Thanks again
Steve

 

Yes the smoke you see coming out of the tailpipe hurts both mileage and performance. The smoke is basically unburned fuel. Unburned fuel hurts both mileage and preformance. Obviously the more smoke the more damage done to mileage and performance. Usually running an engine that is smoking lightly does no damage. Sometimes the smoke is caused by one cylinder misfiring. This can be determined by opening the high pressure fuel line to each cylinder. When you open the line you should be able to hear the cylinder miss. If you have a really bad injector on that cylinder. You won't hear the cylinder miss Another thing that will cause smoke is somebody getting a little gasoline in the Diesel. To check for this problem simply open any fuel line and put a little of the fuel on a piece of paper towel. Then see if you can light the paper towel with a match. If the fuel burns on the paper towel you have gasoline in your Diesel.

 

ah, just turn the fuel to her, it'll go away

 

mechanic-so you say pull the fuel line? Don't I need to cap it or something? will fuel spray every where?
Sorry for the ?'s
Thanks
Steve

 

You don't have to remoe a fuel line, Just loosen a line.Don't use an injector line as there isn't much fuel coming out. warp a chunk of rag around the loosened fitting and when the rag becomes soaked tighen the fitting and take the rag over to the bench and try to light it on fire with a match . If the rag lights you have gasoline in your Diesel. You can also just loosen the fuel filter and dip alittle of the fuel on a corner of a rag.

 

Gray smoke is often cause by the fuel injection timing advance not working properly, or out of adjustment. Try advancing your static timing a few degrees and see if any improvement is observed. As far as setting an injection pump too lean, yes you can. It won't hurt the engine like a lean mixture can in a gas engine, but . . . set the fuel delivery too low in a diesel and it will be very hard to start, and be underpowered.
In regard to factory settings - they probably wouldn't go you any good. Fuel delivery is adjusted two ways to meet specs: #1 while the pump is apart - air or hydrualic pressure is backfed into the pump-head/rotor and the expanded rollers are set to a certain dimension with a micrometer or #2 once the pump is reassembled it is run on a test stand and output of each cylinder is checked at various speeds and the leaf-sring screw used to adjust.
If you know a certain engine well, it's pretty easy to set the fuel delivery by "trial and error" with the pump on the engine. Some engines, especially on industrial and farm equipment, come detuned from the factory, and you can get an easy 10%-20% power increase just by turning the pump up. This does NOT seem to be the case with the IH V-8s in Ford pickups, or GM 6.2 and 6.5s. These engines, more or less, come from the factory set at an optimum level, and turning up the pump without doing any other mods. usually gives - at best - a modest increase in power and can cause some cylinderhead/exhaust gas overheating issues.

 

thanks for the info guys.
I will check the timing.
How can I check the injectors to know if they are working right?
Thanks again
STeve

 

The best way is to remove them from the vehicle and take them to your local frindly diesel injection shop or most Diesel shops will have a pop tester to check the injectors.