My Cummins 5.9 in my '93 U225 has started smoking a lot under dul throttle. I noticed about 250 miles ago returning to Tucson. My tail pipe is now completely black. Oil, air filter , etc. changed about 7000 miles ago just before heading out on a long trip.
Could this be air filter, turbo, other? Thoughts?
Roger Worley
Turbo, turbo piping lose leaking, charge air cooler cracked?
Could be an air issue. Have you been on a lot of dirt roads lately?
More knowledgeable people will be chiming in soon.
Agree with Bruce.
Start with the easy stuff.
Verifying that you have enough AIR. So, air filter OK, plumbing to and from CAC OK, exhaust manifold to head not leaking, manifold to turbo not leaking.
What does the fuel in your primary fuel filter look like?
Any change in oil level or oil viscosity?
I am sure others with more Cummins B experience will chime in.
What color smoke?
X2- and then, depending on the color, Google to the rescue:
Discover The Causes of Diesel Engine Smoke By Color (https://dieselcomponentsinc.com/diesel-engine-smoke-by-color/#:~:text=Any%20variations%20from%20the%20original,internal%20problem%20with%20the%20engine).
Black smoke and soot is not enough air, so you are either loosing boost, or you have an intake restriction. You can make a boost leak tester with a pvc pipe cap that fits in the intake hose and put an air fitting in the cap. Get a pressure regulator or just turn down the pressure on a compressor and put 10-20 lbs in it, then listen for leaks or spray some soapy water on the connections.
Could also be one or more bad injectors or an engine problem.
A failed injector is usually accompanied by a lost cyl power. Does the engine skip at idle ?
Still need to know the color of the smoke. Then, also need to know which fuel pump you have. VE rotary pump or P-7100 inline pump. '94 was the first year of the P pump in the Dodge pickups. Before that were VE pumps. Need to determine which one you have.
VE Pump Versus P-Pump: Inside The Most Popular 4BT and 6BT Cummins Injection... (https://www.4btengines.com/ve-pump-versus-p-pump/)
Smoke is black; tail pipe is black with soot. Engine idles smoothly.
Black smoke, soot, is more fuel than you have air for. So loss of combustion air supply some where in the incoming air lines, air filter, CAC, tubing joints and turbo.
Yes
Check for intake restrictions. At idle , no boost. So the leaky pipes won't show up.
Fuel pump is the inline pump; six separate outlets on the top.
As mentioned, black smoke means fuel without enough air/boost. Boost leak most likely. Start with the easy stuff...look at the hoses between the turbo outlet and CAC piping, at the CAC and into the intake. Look for any signs of a hole or loose clamp(s).
Take the intake hose off the turbo and look at the compressor wheel. Give it a spin with your fingers. Does it look undamaged and spin freely?
Diesel is clear; maybe slightly green/yellowish.
Checked air cleaner; has about 7000 miles on it; looks like new.
Disconnected the turbo inlet; turbo turns freely.
All hose/tubing seems tight; no breaks/cracks found.
Engine oil level is a little low
Have not tried to pressurize the system yet.