chugging and heavy smoke question 6.9

[beve5]

Got a question. I have a 1986 F350 with a 6.9 and manual transmission. Recently it started smoking heavily (black smoke). Also there is a strange chugging or puffing noise from the exhaust. When the intake breather is off the puffing or whooshing noise is very loud from the intake. The idle is also very ruff but rythmic. The entire truck will shake at idle. The engine smooths out as the rpms rise but the black smoke continues. Due to the 180,000 miles on the truck with nothing done to the fuel system and the brittle and leaking return fuel lines I have already installed a new fuel filter, injectors, return fuel line kit and rebuilt injector pump. All of this made no difference in the way the truck idles and the heavy black smoke from the exhaust remains. Anyone got any ideas?

Thanks,
Dave

 

[riphip]

Timing would seem to be retarded a little. The wooshing would have seemed like a valve but you say it smoothes out at higher rpm. Advance the pump timing about a dime's thickness to the passenger side & see if it improves a bit. Doesn't take much. Also add 1/2 gallon of chain saw bar oil to each of your tanks to help the low sulpher fuel. It's cheaper than regular oil w/o detegents & will do good for testing. I usually add some DieselKleen w/Octane Booster to mine after that. About 3 glugs from big bottle to each tank.

Rick

 

[Agnem]

A compression test would be a good idea. The black smoke rolls pretty constantly, or is it just under load?

 

[beve5]

The smoke is constant. I wish I had the equipment to do a compression test, but I don't. I will take it to someone as a last resort but I'm too cheap to do it unless I have to. I think I'll pull the valve covers this evening and see if I can determine any problems there.

Thanks,

 

[65sixbanger]

Maybe your fuel selector valve needs to be replaced???

 

[beve5]

What's a fuel selector valve? Can you tell me where it is and how to check it?
By the way, advancing t he timing did not help.
Thanks,
Dave

 

[Mat J]

Is your air filter clogged?

I would take it to a shop and get the pump timed right also.

 

[91f2504x4]

Sounds like you might have a valve train issue, I had a similar problem where a rocker arm loosened up and was not opening the exhaust valve completely so it was chuffing/popping back through the intake. Sounds like your intake valve might not be opening all the way and you're not getting enough air to burn the fuel, and therefore leading to excessive smoke. It will be very evident if one of them are loose if you pull the valve cover off and have a look, try to wiggle each of the rocker arms, you might have rotate the engine over a time or two to check each of the rocker arms, just make sure that the cylinder is on the compression stroke when checking that cylinders rockers for being loose.

 

[beve5]

Thanks a bunch to all that replied. Should have listened to agnem to start with. I broke down and purchased a compression test kit (120$). 1 and 3 cylinders have only 20 and 80 psi and I think the guy with the post about the valve train was right on. The other cylinders are between 350 and 400. I will be pulling the valve cover tomorrow. This site is great for someoneike me trying to learn as he goes.

 

[dyoung14]

Thanks a bunch to all that replied. Should have listened to agnem to start with. I broke down and purchased a compression test kit (120$). 1 and 3 cylinders have only 20 and 80 psi and I think the guy with the post about the valve train was right on. The other cylinders are between 350 and 400. I will be pulling the valve cover tomorrow. This site is great for someoneike me trying to learn as he goes.

if two cylinders are low then its more than likeley ate a headgasket

 

[beve5]

Have the truck running well now (actually better than ever). Turns out the head gasket was blown between the 1 and 3 cyclinders. But after all the miles the heads, block and pistons looked really clean and seemed to be in great shape. The injectors and pump I put on were definitely worth it since the engine has more power than the last few years. And I also took you guys advice and had the timing done correctly (dynamicly). It now runs better than new. A final compression test with the high dollar equipment at the mechanic shop showed all cylinders near or at the 400 mark.
The articles and advice from this site was great.

Thanks,
Dave