My Dad just gave me his 88 Chevy c2500 with 6.2... this is my first diesel truck. The truck has 74k original, once he retired he stopped drive it all the time. My question is this truck blows black smoke something bad. Not at idle rmps, but once your foot is on the pedal it starts. And I don't mean floored, just maintaining speed its blowing black. I replaced the air filter today when he gave it to me cause he said he had not replaced in a while. When changing the filter I noticed the air inlet into the manifold (not sure what the part under the air cleaner is called) is loaded with black soot. Is this normal? How do I clean it? Should I clean it? Is there a fuel additive I should add? My Dad said someone told him maybe it needs injector thats why its blowing that much soot. If you guys could please advise, that would be great. Thanks in advance. Craig  

If you had some photos to post, that would help. As long as the filter itself wasn't real sooty, then you're probably okay. My guess is there might have been some sort of EGR system on that motor that recirculated exhaust gases back into the combustion chamber. N.A. diesels will smoke quite a bit normally (more than unmodified turbodiesels, in most cases) but shouldn't be belching black smoke. Other than it smoking a lot, does it seem to run OK? Does it stall out or idle rough or anything?  

The truck runs great.  The filter was dirty but not with soot.  The soot is at the base of the "thing" (sorry I would call it the manifold) the air cleaner fits over.  My Dad said it did not always smoke that bad.  

Sorry. I'm not a big expert on these engines. You might want to check out http://www.62-65-dieselpage.com for more detailed information & tips. Sounds like the engine might be over-fueling a little.  

OK,thanks will do.  

How long has this engine sat for?

Most 6.2's don't like sitting around for long periods, so your best bet would be to run a couple tanks of #1 diesel and a few bottles of FPPF in each tank.  Take it out and run it hard with a decent load or pulling a trailer.

My dad used to run 6.2's and we picked up one after it had been T-boned in an accident.  It had set for about a year and there was nothing wrong with the powertrain, but it did need a new frame so we pulled the engine and tranny and dumped it into a different truck and had the exact same problem you're describing.

We ended up doing an emergency tow (moved a tractor trailer off the road we were escorting) and the amount of black crud that got blown out fixed the problem.



Kris  

He would use it maybe once/twice a month for the last 8 years.  Nothing far or with any load and never put his foot in it.  He would start it and let it idle to charge the batteries.  

What FPPF product? I see they have a few.

Another forum/site said EGR is bad.  Take the manifold off and clean it and reinstall it. Replace or bypass the EGR.  I was thinking maybe I could vacume out the soot from the manifold with a soot snake (flexable shop vac attatchment).  

craigrep:
He would use it maybe once/twice a month for the last 8 years.  Nothing far or with any load and never put his foot in it.  He would start it and let it idle to charge the batteries.  

What FPPF product? I see they have a few.

Another forum/site said EGR is bad.  Take the manifold off and clean it and reinstall it. Replace or bypass the EGR.  I was thinking maybe I could vacume out the soot from the manifold with a soot snake (flexable shop vac attatchment).

Either that, or give it a good soaking in carb or brake cleaner. Also, get it out on the road and drive it good & hard to blow some of the soot out.  

FPPF Fuel Power.

Add it to the fuel tank and fill up.  I've run it in the last 3 diesels I've owned, including the one I just traded in.

Because of the amount of soot you're blowing, add about 3 bottles to the tank and fill it with #1 diesel.  The higher cetane rating in #1 will help burn off the carbon build up.  Also try the EGR fix as well ..... soak it overnight in carb cleaner and that should fix it.

Like I said before, take it out and run it hard preferably with a decent load.  Every 6.2L diesel my folks owned would carbon up like mad and usually about two or three times every fill up if you got on it hard it would crank out a pretty big black cloud.


Kris  

All you are seeing is soot that has came loose on the inside of the pipes from sitting. Just run it. I would put a 180degree stat in it and take a piece of 3/4" round stock about 3/4" long and drill a 3/16" hole in it length wise and put it in the hose that goes from the water pump up to the water manifold. Also the injectors are ok I don't think I have ever seen a 6.2 injector go bad.  

Ditto on the no bad injectors for the 6.2L engines.  My folks were running 7 of them at one point.  The lowest mileage truck we had was 17,000 (bank purchased repo) and the highest mileage was 285,000 which ended up getting rebuilt for long distance hauling and towing.  It was a 2500 Suburban that got a 1 ton suspension transplanted underneath it.  I even used it to take my first and only driving test in it.

The low mileage truck was my Dad's personal rig (Chevy Custom Deluxe 1500 standard cab) and it ended up seeing more than 185,000 tick off on the odometer before it needed a new 700R4 tranny (his own fault, ATF got too low and burned up the clutch pack).

The only complaint I've ever had with the 6.2L is it leaks engine oil like mad, but a little kitty litter or floor dry picks it up pretty good.



Kris  

Absolutely, it just needs running!   Be sure (SURE!) you add a fuel lubricity improver to each and every gallon of fuel, the new diesel formula will destroy the injection pump in short order without added lube in the fuel!

Take it on a Interstate run of at least 100 miles.   Run it hard until the governor kicks in and shuts you down, then run the rest of the trip at about 85% of that speed.   If it has an overdrive transmission, you may need to pull it back into direct drive in order to run it hard without getting hauled off by the Speed Gestapho!

Bruce