S/N: CW924630 Machine bogs down after running for awhile. Sometimes after you dig into a pile or if you just sit at high idle, it'll bog down. I sent it to CAT because it still had warranty. They did a fuel pump calibration and couldn't recreate the issue so they said it was good. We ran it for 1-2 weeks with no issue. Then it did the exact same thing. Sent it back to Cat and they ran it off a separate fuel supply and said there must be something in the tank. We drained the fuel, stuck a camera in there and couldn't see anything obvious. I drilled more holes in the pickup tube thinking it might be something bigger covering the hole. We ran it and it had the same issue. One of my mechanics took the rubber line off the intake side of the fuel filter and blew air back into the tank. He heard a pop and it ran fine for a week or so. Came back in again with the same issue so I did the same thing as my mechanic. This time I pulled out the pickup tube and covered it with a rag and shot air in the line hoping to catch whatever might be in there with no luck. What else should we check?
The issue is in the filter head, at the inlet elbow, or under the pump. Start at post #9 here HeavyEquipmentForums And read all the way to page 3.
We have several CW9 machines and many of them have had the same symptoms. I’ve managed to collect the large chunk of rubber that is plugging the suction line coming from the tank. I haven’t figured out where it comes from. Usually once I get it out, the problem doesn’t return.
And don’t forget to drain the cr@p out of the tank, because that’s where all the problems are coming from.
To clarify, did you pull this tube out of the tank, or just the steel line going to the filter housing? #3 in the image
We did pull out #3
I only see a bowl seal kit for this model, nothing for the actual pump.
Not much serviceable on this pump assembly, PN: 630-7959 If the pickup tube and line going to filter are clean then whatever you blew back into the tank is blocking the flow at random.
Cat doesn't sell the pump separately on the filter head. It's a Stanadyne, and available aftermarket.....but, you just need to disassemble what you have and clean the inlet elbow and the pocket that the pump sits in, along with the outer concentric stem that goes in the center of the filter.
I had one of my guys dissassemble the filter head and he said there was very minimal debris in there. Nothing he thought that would affect anything. He doubled checked the tank and lines and put it all back together. Hopefully in a few days I can get someone to test run the machine and get a concrete answer.
Did he remove all the fittings from the head and check them, or at least blow through them with compressed air.?
All fittings were removed and had air blown through. He put it back together and it ran fine for a day or two, then the bogged down again. My next thought is to somehow check voltage at the pump while it bogs down to rule out the electrical side of it.
Did anyone ever drain the water/cr@p from the tank.?
We have at least twice now. Stuck a camera in there and could not find anything. We even flushed it with fresh fuel and no contaminants came out.
Sent it back to Cat and they are saying something has to be in the tank. Need to remove the engine to be able to take the fuel tank out. I'm getting a quote from them for it. Has anyone had to do this before?
If they say that then IMHO you should get it in writing that if they find nothing in the tank after removing it then you are not on the hook for the bill.......
I’m thinking I ended up getting 3 fat chunks of rubber out of the 259D3 before it finally quit doing it. Haven’t been to it for that issue in over a year now.
If something in the tank is blocking randomly, a vacuum gauge teed into the line from tank to fuel filter would show it instantly. Does the top of that tank afford a guy the ability to put a plastic pipe down to the bottom and corners with the pipe hooked up to a 20 liter suck pail that is clean for a vacuum. Would not have to suck too much out to get dirt from bottom that is hiding. You can even blow some air into the bottom as you twirl the pipe to loosen any chunk that might be in a corner. Wouldn't take too long and easier than tank out. Simon C
It sounds like a restriction in the fuel system is hiding somewhere, now just to find it. Building off of SimonC's idea, using a vacuum gauge tee'd into a hose going into an air operated fluid evacuator, you could suck fluid out at several points along the low pressure fuel supply system to see if you can identify where the restriction is occurring. A bit of a science experiment, but if it works, it would save an engine pull.
ahart, What size was the "large chunk of rubber" that you found in your CW9 machines?
Probably 6mm diameter, it blows through the steel tube with compressed air but never made it to the filter.
Can you elaborate on how to use the fluid extractor in this instance?
Just had another 259D with this issue. Found the rubber chunks in the steel tube between the filter and the tank.
My thoughts on using a fluid extractor is to check the low pressure fuel system for any hard to detect restrictions, which appears to be intermittent. In effect, using a fluid extractor to suck on the low pressure lines to check for a restriction, as opposed to blowing through the low pressure lines using compressed air. From what I can see on the parts diagram for your 259D3, you can break your low pressure fuel supply system down in to sections: 1) Fuel tank to inlet of fuel filter assembly 2) Fuel filter assembly includes low pressure fuel pump, fuel filter and water separator 3) Outlet of fuel filter assembly to inlet of fuel injection pump I suggest that you check each of the above sections for restrictions using a fluid evacuator first with all sections combined (sections 1, 2 and 3). Do this by disconnecting the low pressure inlet of the fuel injection pump and seeing if you can use the fluid evacuator to draw a continuous volume of fuel from that point. By teeing in a vacuum gauge when doing this, it might give you a relative idea of the resistance in the system. You also might also want to see how much fuel is recovered in a period of time. You might not be able to recover any fuel, at which point you would not know where the restriction in the low pressure fuel system was. You would then go on to check sections 1 and 2 combined using the same process. Then check section 1 by itself. Depending on your results, you might even want to test sections 1, 2 and 3 individually to see if you can even draw air through them without being connected to the fuel tank. The idea is by process of elimination, try to determine if and where the restriction is in the low pressure fuel system. On the fuel line diagram, item 4 is listed as a relief valve on the low pressure discharge line from the fuel filter assembly. It may be worth paying special attention to this relief valve during your troubleshooting ... not from any personal experience, but rather from checking everything in the low pressure system. As I said before, a bit of a science experiment but it may produce some results.