Engine starting to gave black smoke

[Jason Worman]

Hi everybody,

We took the old girl out on the road for a weekend getaway. Upon starting we usually have 2-3 minutes of white/blue smoke that clears and stops. Today while driving, black smoke puffed out on each start and stop and continued for a minute or two. Engine ran just fine, destination was about 60 miles away. We are parked and will leave on Tuesday after holiday traffic clears out. We have the Cat 3116 engine. Only difference today I did stop and fuel up, roughly 60 gallons. Rig normally sits about 10 days between black tank dumps.

Thank you,

Jason Worman

[Dave Atherton]

Jason, what you have happening is the fuel rack that operates injector is sticking. This is a
Mechanical fuel system and very common place to look at is the linkage pin connect the fuel
rack. Location is between the governor housing and valve cover body at this location you will
see a 2 inch gap between the valve cover body and Governor housing via a round tube with a
metal retaining clip that keep metal tube in place. Using channel lock pliers to remove retaining
clip than slide metal tube into valve cover housing. At this point you will see a pin that is connected
To the fuel rack . Note: remove this pin and the pin cannot fall into the Governor housing or
into the engine. This is where your fuel rack is sticking or rusted from moisture over time. To
be extra sure of fuel rack movement, remove the valve cover and the fuel rack is in plain view.
Again note: your injectors are Detroit injectors look alike and you can see the movement on all
Six injectors. With the linkage pin removed movement of fuel rack can be done by hand to check
Travel of fuel load on each injector.. in closing, first place of problem location at linkage pin,
second look real close at fuel rack movement back and forth because fuel rack can be sticking
at one injector. This engine was built just before the electronic 3126 A model Cat. Setting for
Your injectors and fuel are all mechanical and requires special tooling and technical information.
I can walk you this problem and follow up hard copy service specs. Because it is a very good
Mid size engine we are stepping back in time to early 90’s. Dave Atherton Retired Cat Mechanic

[Jason Worman]

Dave,

Am I okay to drive? I will be back on Tuesday and will give you a call on step by step directions where everything is located.

Thank you,

Jason Worman

[Dave Atherton]

Jason, you can drive but keep a eye on the exhaust smoke, if it turns black and stays black
running than shut engine down at that point you are over fueling cylinder with diesel fuel.
Where are you located close to AZ any chance. I have the tooling to check and reset the fuel
rack. Dave

[Jason Worman]

Dave,

I am on the Oregon Coast

Jason