1979 FJ40 Fuel pump woes (1 Viewer)

[Stumper]

I have a 1979 that has been sitting for quite a while. Gas tank was empty, motor/carb has been rebuilt, including new fuel pump...but that was about 8-9 years ago.
It will start on starting fluid or by pouring gas in the carb, but not on its own. I thought that maybe the lines may be blocked, but after pulling them all, they were all clean. When trying to start it, it will pull gas from the tank, but not a lot, and start filling up the fuel filter. Filter is new as well. I pulled the filter and blew through it and it is unrestricted. When I pull the line off from the outlet of the fuel pump, no gas comes out when turning over. Is it possible the fuel pump has gone bad for sitting for so long? It was last run about 6-8 months ago, but just around the block, and before that, hasnt been run much in about 5 years.
Is it possible the pump has gone out, or should I be looking at other options?
Thanks for the help!

 

[78fj40mg]

Most likely its the fuel pump, .or it could be the carb needle valve sticking. You may want to tap the carb fuel bowl a few times to try and loosen the needle valve and see if she starts, also try pulling the discharge hose from the fuel pump and crank the engine and see if fuel is flowing before you replace the pump.

 

[Stumper]

Thanks for the quick reply....
I pulled the fuel inlet at the carb and cranked it and had no fuel incoming....basically no gas getting to the carb.
I pulled the soft outlet hose going from the pump to the hard line leading to the carb, cranked and got nothing at all.
The curious part is that the truck has been sitting for months and months, tank empty. When I pulled the lines to check for blockage, I was getting gas coming out, and getting minimal gas to the filter....so I have the pump pulling from the tank, just not moving out of the pump to the carb.
I looked and saw that there are no rebuild kits available, I just hoping I wasn't missing something simple or less obvious beyond having to replace the pump....especially because the pump was OEM brand new about 9-10 years ago, and hasn't had that much use. Albeit, it has been sitting in the elements for a number of years....possibly drying out the diaphram in the pump.

 

[78fj40mg]

I think its the fuel pump and don't believe you can get a rebuild kit, your only option is to get a new one one, of our vendors sells fuel pumps check with @Racer65 he may have one for you. For OEM I would check with @beno

 

[Solace in Solitude]

Sniff your dipstick and make sure your pump isn't flooding your crankcase with fuel. Fuel in your crankcase indicates the fuel pump diaphragm has failed and the pump needs to be replaced.

If there is ANY chance there is fuel in your oil, change the oil and filter... So the fuel doesn't ruin bearings, etc.

If your tank has been sitting empty, "for months and months", consider what varnish or gunk may have dried in the tank... Then you added new fuel... It may have caused flakes or small chunks of 'something' to flow from your tank and clog your fuel filter. Have you checked your fuel filter again, to ensure it isn't plugged?

If you don't have fuel in your crankcase, I would pull the tank and clean it... Then pull the fuel pump and clean it and ensure it isn't simply blocked... Clean your fuel lines again... Change the filter again and see what happens.

With the line, to the carb, disconnected and pointing into a receptacle, 15 seconds of engine cranking should result in about one-half cup if fuel in the receptacle. If you don't get enough fuel, you either still have a flow restriction or the pump needs to be replaced.

Good luck!

 

[Stumper]

Sniff your dipstick and make sure your pump isn't flooding your crankcase with fuel. Fuel in your crankcase indicates the fuel pump diaphragm has failed and the pump needs to be replaced.

If there is ANY chance there is fuel in your oil, change the oil and filter... So the fuel doesn't ruin bearings, etc.

If your tank has been sitting empty, "for months and months", consider what varnish or gunk may have dried in the tank... Then you added new fuel... It may have caused flakes or small chunks of 'something' to flow from your tank and clog your fuel filter. Have you checked your fuel filter again, to ensure it isn't plugged?

If you don't have fuel in your crankcase, I would pull the tank and clean it... Then pull the fuel pump and clean it and ensure it isn't simply blocked... Clean your fuel lines again... Change the filter again and see what happens.

With the line, to the carb, disconnected and pointing into a receptacle, 15 seconds of engine cranking should result in about one-half cup if fuel in the receptacle. If you don't get enough fuel, you either still have a flow restriction or the pump needs to be replaced.

Good luck!

Danny,
Thanks for the reply.
The tank was cleaned and coated during a rebuild years ago. I pulled the filter and blew through it with no restrictions and it is looking pretty clean of sediment as well. I will pull the dipstick today and see if I have fuel in the crankcase. I think that will ultimately tell me if the pump is bad or just blocked up.

Thanks for the help.

 

[Shark56]

Take your gas cap off, blow air back through fuel line from filter connection. You should hear air bubbling in tank. Could be your fuel pick up in tank is blocked.

 

[Stumper]

Take your gas cap off, blow air back through fuel line from filter connection. You should hear air bubbling in tank. Could be your fuel pick up in tank is blocked.

If I hear gas bubbling from the tank while doing this, my fuel pick up should be OK? If no bubbling, pick up is blocked?
I am getting very little gas to the filter while cranking at this point. Showing that the pump is somewhat working in pulling gas from the pump, and not working at all pushing gas to the carb.
Just wanted to clarify...

 

[Shark56]

Yes, bubbling means your pick up is likely to be clear. With the cap off and line unhooked from filter you should have some fuel drain from the tank. Just by gravity.