Archived Fuel Pump Problem.

[wildmanben]

98 12v 5sp. Just got it all back together after the headgasket and went to bleed the lines out. I have got fuel from 4,5,6 and nothing from 1,2,3. No bubbles or anything. A buddy and I tried doing things for 3 hours without any results. Its been sitting for 2 weeks with the lines open. Could this be a lift pump issue or is there just that much air in the pump? Need help soon. :{

 

[wildmanben]

been doing some searching on here and found that I should check the return/supply lines for leaks? The lift pump is usually the last thing to replace in this situation also?

 

[Joe G.]

Will it try to start on those three cylinders? I took all of the injection lines off my truck clean the ugly chipped paint off of them. There were completely empty when I put them back on. I have heard that you can start a 12 valve that has run out of fuel without having to prime it. It took three cycles of running the starter and letting it cool before it started. When I did start it banged around for a little bit until all the cylinders get in the act.



You can CHECK the lift pump to see if it is good or not. Replacing it on the hope that it is the problem is not a good idea at all.

 

[wildmanben]

It will start and run if you hold the skinny pedal to floor. But the other lines just wont spit the fuel out.

 

[Joe G.]

It doesn't sound like a fuel supply problem at all. No fuel or insufficient fuel to the injection pump will not isolate to individual cylinders. Check your fuel pressure. If it's at least 18 PSI then the fuel supply system is working. If the pressure is much lower than that then the fuel supply is not delivering the fuel. It looks like an injection pump problem to me. I really don't know because I have never had an injection pump problem. Hopefully, someone with experience with that kind of problem will help.

 

[wildmanben]

Yeah this is really bugging me, I havent had time to work on it today but hopefully tomorrow I can dig into it. I was going to try and replacing the supply/retunr hoses off the lift pump and see where that gets me.

 

[tp0d]

Have you tried leaving the 3 bad lines cracked and running the engine on the good 3 until you get fuel at the other three? Strange you got prime on only 3 though... hmm. .



If you have fuel at 3 of the lines, your fuel supply lines should be good enough to get the truck running again. If you had that much air, all the high pressure lines would be affected.



good luck



-j

 

[wildmanben]

ok so I did some more research and testing and found that the lift pump is not pumping much at all. It will pump to the filter housing, but if I open the bleeder on the overflow, nothing happens. Went outside to the tractor and tried the same procedure and fuel sprayed everywhere when I pushed the primer down.



So does this prove that the lift pump is faulty?

 

[Joe G.]

Remember that the lift pump won't pump air. So if you have an air leak before the lift pump it will look like it failed.



There is some info about this in two parts:

here:

http://dieselram.com/ubb/ultimatebb.php?ubb=get_topic;f=45;t=000007

and here;

http://dieselram.com/ubb/ultimatebb.php?ubb=get_topic;f=45;t=000006

 

[wildmanben]

The fuel heater was leaking so I took it out and now it runs, thanks for the help guys!