Cat 3116 fuel pump issue?

[WillWagner]

Steven, PLEASE use punctuation!

 

[Eliteweapons]

What did it turn out what's wrong with it my truck did the same thing 2 months ago and I still have not figured it out I have replace the check valve the main line going from the tank to the pump fuel filter water separator the two valves Inlet and Outlet at the pump and also some old rims for truck will start and run on starting fluid but is not getting fuel

Did you check the fuel shut off solenoid and switch? How old is the diesel in the tank? Is there any algae in the tank? Does it run with fresh fuel connected directly to the pump inlet?

 

[steven stuchell]

It has fresh fuel the transfer pump was just rebuilt new fuel line new water separator new fuel filter new check valve at tank and I'll check valves in the pump including piston replaced fuel is clean no algae in tank can't figure out how to get it to Prime

 

[glcaines]

The 3116 CAT engine in an M35A3 can be notoriously hard to get air out of the fuel system. The fuel filter sits upside down, so you can't fill it before installation. Just changing the fuel filter can require a lot of engine cranking. I've found that after I change the fuel filter, the best thing to do is open the drain valve under the fuel filter and crank the engine over for about two minutes with the drain open. I only crank the engine for about 10 seconds and then let the starter cool for a couple of minutes. Normally, the engine will start prior to reaching two minutes and sometimes in as little as 15 - 20 seconds. When it starts, I just let the engine run and then reach under the truck and close the valve. I once had an issue like you and it took around 5 cranking minutes to get the air out of the system. The biggest weakness on the A3 fuel system is that the check valve over the fuel tank takes very little trash to plug it up. I never go anywhere without wrenches to remove the check valve and clean it out.

 

[steven stuchell]

Yes I changed that with a new one I'm not 100% sure why the truck died at idle but it has been two months and now has fresh fuel lines check valve at the tank rebuilt the transfer pump new water separator and fuel filter I am wondering if we might have one of the valves in the transfer pump backwards cuz I cranked it with the separator valve open and it spit out a bunch of fuel and then nothing

 

[glcaines]

Yes I changed that with a new one I'm not 100% sure why the truck died at idle but it has been two months and now has fresh fuel lines check valve at the tank rebuilt the transfer pump new water separator and fuel filter I am wondering if we might have one of the valves in the transfer pump backwards cuz I cranked it with the separator valve open and it spit out a bunch of fuel and then nothing

If the fuel filter is full and the separator valve is open and nothing comes out when you crank, don't trying starting the engine anymore until you find the cause and correct it. Continued cranking only puts wear on the starter and those starters are expensive. If the check valve on the tank is good (you replaced it), I would then disconnect the fuel line, connect an electric pump to the line and see if you can pull fuel from the tank. If there is an air leak, you may be pulling air into the lines.

 

[snowtrac nome]

I may be mistaken as my memory doesn't work like it once did I think the 3116 uses a gear pump like a 2 cycle Detroit if the pump isn't wet it wont suck thats why I usually suggest pressure priming the system so you can force fuel into the pump. Air in the fuel system is one of the biggest problems with the 3116 if too much air is run through the injectors it will ruin your injectors the repairs can be expensive and difficult. I just dealt with a 3116 that ran out of fuel to get it to restart I had to pressureize the fuel system with air to force fuel up to the pump while cranking to get the pump to draw fuel again.

 

[steven stuchell]

Yes I'm thinking it is a valve at the return line and it is not allowing to build pressure

 

[Monkeyboyarmy]

3116 uses a piston pump in the governor housing. It has a check valve before the pump and a pressure relief valve where the fuel exits the front side of the head.

 

[Monkeyboyarmy]

There is no filter before the piston pump. I've seen debris get into the check valve and hold it open.

 

[steven stuchell]

We got it running the check valve in the return line was clocked came out in pieces put in a new one cleaned out all the lines with air primed it started right up