excessive black smoke...

[IHWillys]

Last fall I purchased a 1985 F250 with NA 6.9(just for the engine). It is a high-altitude model(158 HP) by the sticker on the valve cover. I live in Colorado and a friend of mine is going to be using it a few months to tow a 6000 lb trailer around locally. It will be used from 5K feet up to 9K feet(no highway). I have a question about the excessive black smoke(extra fuel) it produces. Here at 5K feet it easily produces black smoke with very careful throttle application, let alone if I "get on it", all with no load and on level ground. When going up an incline it smokes if I try to maintain speed(not fast, ~6% grade, unloaded and no trailer).

It has just under 200K miles. I have no idea of the history(like injector age, IP age, etc). It starts easily off the manually controlled glow plugs and *seems* to have the power a NA at this altitude should have but the smoke is too much.

I figure I need to get it timed and then most likely "turn down" the pump to get the black smoke under control.

Is there anything else I should be looking at?

Could timing alone cause this smoke issue?

Thanks,

Ken

 

[Diesel JD]

From what I hear the issue is the lack of air at the high altitudes. I would probably turn down the pump until you can get a little less black smoke...or it might get melted at 9K feet It seems the only real cure for this issue is to add a turbocharger or get a newer turbocharged truck....just not much air up where you all are,
J.D.

 

[86 1 tonhauler]

make sure ur air filter is clean and ur u have a new fuel filter

 

[dbarilow]

the P.O. might have turned the pump up or put a non High altitude pump on. I would get a pyro in there to keep pistons from melting.

 

[RedTruck]

Ken,

When you have it in for timing I would have your injectors pop tested. Many guys here will take them out themselves and bring them in to have tested. This lowers the cost of shop time. I'm thinking the injectors aren't atomizing the fuel like they should, consequently you aren't burning all the fuel... this could also be caused by the IP.

Let us know what you find out.

Paul

 

[Compu Doc]

Of course there is no such thing as excessive black smoke when your nextr to a rice burner with his stereo way to loud and his windows rolled down.

Black smoke comes in handy then

 

[RLDSL]

Try turning down the fuel a flat or two then try advancing the timing a little bit at a time until it acts better.
It kind of sounds like someone tuned it for sea level.

----Robert

 

[IHWillys]

Thanks for all the responses. I guess I just wanted reassurance that there wasn't something else I should be doing. Yes, testing the injectors would be a good thing but I'm working on a zero budget here. I bought this truck to take the engine out and rebuild for a swap. This all happening over the next few years(it's amazing how much I've slowed down projects now that I have a young family). In the mean time I had this truck just sitting and a good friend has 2 trucks down and a need to occasionally pull his trailer for work so I offered it's services.

I hadn't worried about the smoke when I bought it because I knew my plans didn't include driving it as it is, but now it needs to be useable for a little while.

I think I'm going to turn the fuel down quite a bit, he can deal with the lack of power for free use of a truck and I then won't have to worry about melted down pistons or such, and he won't get dirty looks spewing all that smoke(his name and phone are on the side of the trailer), he'll just get dirty looks for the slow going in the canyon(Big T).

Thanks again,

Ken

 

[Agnem]

If the injectors are original, or high milage, I would pitch them and go with a new set. They are probably not even atomizing the fuel anymore, and peeing it in a stream. That will really get the smoke rolling. That, and a low pop presure will have advanced the timing some (but that is probably being compensated for with the worn IP). Read the fuel system servicing article and consider doing the whole shabang. Nothing makes a truck feel like new like a rebuilt fuel system.