We are having problems with our D6k. It looses power and throws a code. We first changed the two Ultra High Efficiency fuel filters. Runs good for about 3 tanks of fuel then repeats problem. Out of four Cat machines only one having problem. Initially thought it was algae in the fuel. Took off fuel tank and steamed it out, washed it good. Have used an abundance of fuel treatment to prevent algae. Fuel stored is clean and filtered twice before putting in machine. Still having problem. Someone told my son it might be the fuel picking up oil when it goes through the pump and part recirculates back to the tank. We have had to add a little oil but not an excessive amount. Do get some black smoke when decelerating machine and letting off decelerator. Has anyone had this problem? How would you determine if it was the fuel pump?
You can send an oil sample and the results will tell you the percent of fuel contamination. You could check to see if a fuel sample will find oil contamination? Are your other Cats similar technology/fuel systems? I'd put a prefilter in the system to catch the bigger stuff and see what happens. Have you torn apart the old filters to see what they look like?
Thanks Delmer. I sent Cat a sample of the fuel from the D6K to see if they could determine how much or if any oil in the fuel. Have not heard back from them yet. The nearest Cat we have with technology/fuel systems to the 6K is a 320E Excavator. Have had no problems with it. Also have a D5G we have had no problems with. Recently rented a D5K 2 and had no problems with it. All using the same fuel. We did cut the two filters and found they were dark colored like fuel in tank, but no visible contamination. I guess we will wait till we see what Cat says about fuel sample. Sent it in oil sample container. Not sure if they can determine if it has too much oil in it. Have you ever seen a problem where engine oil was getting into the fuel system? I do not know about the system. One mechanic said if oil was getting in the fuel, fuel would be getting in the oil. Cat replaced the fuel pump about 1500 hours ago. Old one had external leaks. Filter bill is getting expensive.
I'm not the guy to ask about that. I don't know about that system either, so no use in me speculating on how the oil got there. When you say the filters were dark colored, do you mean dark enough to be soot, or possibly mostly rust etc? How many time have you had to change the filters since cleaning the tank? I wouldn't be surprised to have it happen once or twice, with the dirt that's left loose in a tank.
When filters cut, no sign of rust, water or any visible contamination. Just look darker than normal. When we put fuel in tank it is a clear red. After several tanks, when the the light comes on, power lost and fuel filters clogged the fuel is a very dark red. The engine oil has been in engine long enough that it is black. That is all we can figure. Somehow the engine oil is getting into the system. All I can say is we have done everything I could find out to do for algae and whatever grows in the tank to cause this type problem and it is still doing it. Tomorrow I am going to attempt to find someone with Cat who might be able to suggest a plan of action. Cat put a new fuel pump on machine several years ago because of external oil leak.