Blue smoke, low power

[worldf]

Hello all, I was looking for some help on this issue. I own an 1982 GMC suburban and a 1985 Chevy van and both have the 6.2 motors. I always do all the repair work on these myself until the IP on the Chevy van went out.

I sent it to a locale service guy that was supposed to be very knowledgeable on 6.2's to have it repaired. After I got it back it had no power and smoked blue like crazy when under load. So I sent it back to him and he made some adjustments that made it a little better but not much.

Some info on the van before the IP went south. This thing had crazy power with the old one. It is a short van so it's very light and had "neck snapping" power like a gasoline motor. I could burn the tires with it, everybody who seen it it was like "wow I never seen a 6.2 with so much power". My passing gear was great, I used to fly by people on the highway.

Now however it runs like my slug 3/4 ton suburban, losses power on hills, can't pass on highway anymore, it just a dog now.

First thing I noticed was the pump was retarded to much, so I advanced it. That got ride of a lot of the blue smoke (was like a crazy bug fogger). It still however smokes bad under load and anybody that drives behind me almost passes out from the smell of unburned fuel. Does it still need advanced more?

Not really sure were to go with this now, any help would be great.

Thanks

[93GMCSierra]

possibly a plugged fuel filter?
I have seen that with my filter pretty well plugged, however it this sudden in might not be.

[john8662]

What color smoke does it make when going down the road that is fogging things?

The white/blue smoke is usually a result of timing, but can be other issues.

Can you get a mirror in there to see where the timing reference mark is on the timing cover? If so, compare this to the the mark on the injection pump.

Usually during a pump swap, a little timing advance is used by rotating the pump, usually a little more than a line width towards the driver's side.

I wonder if the pump was originally turned up a little before it was rebuilt.

As mentioned, replace the fuel filters, but should be just the one on an 85.

J

[worldf]

I changed the filter the same time as the pump. Then I also changed it about 5,000 miles later when my lift pump went bad.

As far as the engine timing goes I have not checked. I would not think the mechanic would have moved it on a pump swap would he? When I checked his pump timing mark it was about 2 lines counter clockwise. I moved it about 1 line clockwise.

The smoke is indeed all blue, it used to only smoke black with the old pump at WOT. I always had to clean it off the bumper and whatever I was towing at the time. Now I never get black soot on the bumper.

I also have not checked the return lines for clogging or slow flow. I did however have to go around and tighten bolts around some intake accessories he left loose. I even had a couple loose hose clamps on the fuel lines to the filter he left loose. I never found the leak on short trips only after driving a ways it would fill up the intake valley and run down the bell housing. So I just wonder what else he may of left loose or installed wrong.

I did wonder if possibly my old pump had been tweaked on for better performance but I highly doubt it. The other 2 owners didn't have a clue about diesels. So my search goes on.