Today, I began looking into our cat 420f no start problem. I was told the fuel was contaminated with sludge in tank. Drained and dropped the tank. The diesel looked okay and the tank was clean, not much build of crap. I removed the sending unit. The unit was covered in rust but was not clogged. I'm not real familiar with this machine. I understand it is self priming when key is turned on. Key on and there is no action in fuel system. The filter canister remains empty, don't hear any pump running. The person that brought the machine in said he was able to load on trailer by filling filter canister with fuel. The machine ran long enough to get it on trailer. I checked the fuses, they were all good. How do I check for fuel pump operation? Power supply, location other things I should be looking at? Thank you in advance for any help!
I just googled “cat 420f fuel filter” & up popped several utube videos and filter assy.. It u have a test lite or multi meter, that will get u heading in the right direction.. U could also run a hot wire from the battery to the supply pump to see if it’s burnt out or just needs power.. Good luck..
FWIW. Which isn't much. Did you find the in-line fuel filter ? # 3 is Caterpillar part # 384-8512.
Okay, so, I began by looking for this inline fuel filter and I may be looking too hard but it did not present itself. I unscrewed the filter housing to get a better view. I removed the plastic cover held on by 10mm bolt and zip ties. Well, I'll be...there is a full on control module. At this point it seems I need a wiring diagram/ pin out diagram for the two connectors. Which wire is for energizing the pump? Is the inline filter part of this unit? Maybe near it. I apologize for so many questions.
I wish I could help you, but I all I can do is locate the parts. This is when an Operators Manual would help. That filter could be anywhere between the fuel tank outlet and the transfer pump. You could disconnect the fuel line upstream of the fuel filters and apply no more than 3 to 5 psi. of air to the fuel tank thorough the filler opening. That would certainly show if there the amount of fuel coming through it. I am not a big fan of blowing air into the line at the filters because all it does is blow crap back in the tank.
Thank you, the tank is off. I'll just keep plugging away.
An Electrical Schematic is do-able, but there are a dozen options so to provide the correct one will require the machine Serial Number.
Here is a picture of the vin tag:
Sent you the correct schematic.
I was having problem reaching into the machine because the bucket was down. I have determined there is power to the pump but not pumping. I hooked up an electric pump and primed the machine so i could start it and get the bucket up and out of the way. That worked, so, now, I looking at the pump assembly above the starter. This inline filter that has been so elusive must be part of this. Is that a correct assumption? Any suggestions to keep the bucket secure from dropping on top of me while I am underneath it removing the assembly? Is the failure of this pump and/or the replacement of this inline filter a common occurrence?
The filter is a basic maintenance item and should b replaced 2x a year regardless of what the book says.. I’ve seen so many of those pumps fail.. when they work, they work good..
There'll be a brace like this or something equivalent. If there's not find something, no fuel pump's worth getting chopped in half for.
Absolutely... only the filter pictured above isn't even mentioned in the OMM book.
Thank you for the priceless information.
Thank you for all the help and insight on this machine. I'm waiting on the new transfer pump and should be back in service