IDI Turbo Intermittent Smoke Puffs

[SLawson2000]

Here it goes.

1994 7.3IDI Turbo (Factory), boost upped to 11psi and the fuel pump turned up a bit to match. 4.56's / 34" tires / 4"lift. 130k miles (just a baby).

It seems that my truck has developed a slight smoking problem. Under hard acceleration there is a faint black cloud - I am not too worried about. When the engine is acting as a brake, no smoke - again not worried. But when I am headed down a hill and give it just a little throttle (so there is no load on the drive train) I get a pretty solid constant stream of smoke. As soon as I put a load on it or take my foot off the throttle - no smoke. Also if I go from acclerating to decelrating slowly (about 3 seconds) I get a small puff. The smoke is kind of grayish.

It does not seem to be using oil or coolant, but I am going to start keeping a closer eye on it. I did replace the water pump about 400 miles ago. All the factory guages read normal. Water temp on the low side of normal, oil pressure on the high side of normal, voltage right where it should be. Boost is in range, EGT is fine.

My mileage is down about 1 mpg over the last couple months from 13.5 to 12.5. It seems to run fine. Maybe a little weak in the power department. Starts right up - first try every time.

Any thoughts?

[ta5150]

For a slightly tuned up motor, your symptoms sound pretty much normal. However, since you noted decreased power, increased fuel consumption, and increased smoke at times, check for intake and exhaust restriction. Banged up exhaust, plugged air filter, etc. If nothing is found there, see if your fuel pump adjustment seems to be in the same place as the last time you looked.

If you have an injector crapping out, you may have to wait until it gets worse before you can isolate while the truck isn't moving.

[SLawson2000]

The exhaust looks to be fine. I have not checked the air filter in a while, maybe I should start there (duh on my part).

Hmmmm on the fuel pump. It was turned up before I bought the truck. What is a good way to check the adjustment?

Is there a good diesel additive that I could use to "clean out the innards" like seafoam or an injector cleaner or something?

It just bugs me to look out the passengers side mirror and see a stream of smoke hanging there.

[SLawson2000]

Anyone?