Black smoke

[Tom Hallock]

I have a 96 Chevy 6.5TD an tow a 30 foot fifth wheel, (my home). About 3 month's ago I tried to tow my fiver to another park, unfortunately I was only able to get up to about 20 miles an hour an saw thick black smoke belching out of the exhaust. Turning around, I took the trailer back into my home park an unhooked the rig. As soon as I unhooked an was no longer towing the rig, no more black smoke. Figured that I had to replace the fuel filter. Which was done about a month ago. This past weekend I had to go to Tampa for the weekend. No problem towing rig, even able to get up to 65+mph. But thick black smoke continues. Last year I replaced 2 fuel injector's an a fuel injector pump.
I thought once I had a clean fuel filter all the black smoke would disappear. Any help would be most appreciated.
Many thanx.
Tom Hallock

[patrick m.]

sounds to me like low air flow. maybe boost is falling off.
restricted exhaust is another cause of low air flow.

[Tom Hallock]

Thanks for the post. I have a K&N air filter an I might just need to clean it. Was at an RV show in Tampa this past weekend an looked for their display to buy more cleaser but couldn't find them. Guess I'll have to go to Camping World.
Anyway thenks agin.

Tom

[gmctd]

Also check your vacuum pump for 20" or so, then check at wastegate for 15" or greater at idle.
Could be low vacuum or failing Wastegate Solenoid.

[autocrosser]

If you find that your vacuum and waste gate is opertaing ok look at the cat converter. They plug up and cause the same proble. You can take it loose on one end at the down pipe and leave it open to test to see if it's clogged. I've seen several clogged ones. It's made up of a soft ceramic with thousands of very fine tube running the length of it. It's pretty easy for it to clog up.

[Tom Hallock]

It's also been suggested to me by some friends that maybe my fuel misture might be to rich too an that would cause the same problems.
Trouble is I only notice when I'm under load an not running solo.

[The Gunny]

Tom, this is my first post but I have been a member of the diesil page for about 4 years, this web page has been a wealth of information. I have replaced my boost control module twice on my 96. Same symtems lot's of smoke no power, easy way to check is to apply finger pressure to the waste gate control lever while the engine is at idle ( I can't move mine at all with new module). If you can move this lever then there is not enough vacume to the waste gate and it is opening to soon. This could indicate failing vacume pump, cracked or broken plastic lines, or a failing boost control module. The module is about $45.00 at the dealer and takes about two minutes to change out. :cool: