Fuel systems maintenance today

[Dave Atherton]

Today again problems start at the fuel system that can lead into high dollar repairs when traveling. The fuel system starts at fuel tank in the front of motorhome and ends where fuel exits the engine and returns back to fuel tank.
Problems with components that send fuel to engine can cause low fuel pressure that will result in decreased engine preformance or low power. One of the first indications of problems is having to crank a little longer before startup followed by lot of white smoke. This indicates an air leak in the fuel system that may be very small but allows fuel to leak back to fuel tank. Another area to check is the return fuel pressure regulator on the back of engine head that  returns fuel to front fuel tank. At this return fuel pressure regulator particles can settle over time and not allow check valve to seat all the way. Disconnect the fuel line at the regulator and connect a plastic clear hose and put it into a fuel container. Start and run engine at various speeds. If you see air bubbles in the clear line with engine running you have a air leak in your fuel system. Air within the fuel system can cause injectors to stick or seize up because injectors need diesel fuel to cool the injectors. Low power, heating problems etc. can cause many service shops will address engine problems by throwing parts at problem without properly diagnosing it. I have seen where it has happened many, many times when the problem is very simple to address but can result in very high costs to the owner because the shop failed to check fuel system before engine. Ask Dave. Dave Atherton Retired Cat Mechanic

[Pat Long]

Dave     Is this a problem in any particular model Cat engine or in the full range 3126 to the C15.   I have driven several from the C12 to the C16 and have Never had this happen.    Thank you again for your time and Information.

Pat

[Dave Atherton]

Pat this is a on going problem with all the Caterpillar engines but mainly the models 3126 A,B,E
Cat-C-7 and C-9 Heui injection systems. The bigger engines have a bigger fuel transfer pump to over come most air but has to maintain 90 psi in fuel manifold Cat C-10 to C-15. The builder has
made several areas with fuel line connections that will allow air entry into fuel system. Again the
direction to make a easy way to check your fuel system is the return fuel pressure regulator and
disconnect fuel hose going to front fuel tank and put a 1/2 plastic hose from hardware store and
Connect to Regulator male end and run and hold engine speed steady at different speeds, there cannot be any air bubble except a small trailing stream of pin size bubbles, if you have Air present
start checking all fuel line connections back to fuel tank. Dave Atherton Retired Cat Mechanic