Engine/Transmission (1994 - 1998) aire in fuel

[wrichards]

1998 12 valve runming rough, mechanic says air in fuel, he wants to change my lift pump to electric one in the tank. i changed out the mechanical one in december with one from genos garage. I thought I did a good job with hoses, fittings etc. He says fuel is foamy at the injection pump so its getting in somewhere before that. I took the truck home since I do not want to relocate unless others here think that would be the solution. Any ideas where to look or how to test for the leak?

 

[Missouri Mule]

Air in the fuel sytem could be caused by several things, cracked rubber lines, fuel heater (at connector) ... . Best thing to do would pressure rise the sytem by putting conmrpessed in the tank(don't remember the exact details how to do it so you mite want to do search).



Don't get rid of the manual lift pump! Change your fuel filter to rule it out.

 

[GAmes]

I agree. An electric pump is not nearly as reliable as the stock pump, and way more expensive. You could print this out for the mechanic. http://www.cumminsforum.com/forum/94-98-engine/58777-joe-gs-fuel-system-writeup.html

 

[jeepit]

Absolutely no intank pump!

You will regret that idea.

 

[BIGNASTY]

Absolutely no intank pump!
You will regret that idea.

When my LP went out under Warranty, that was the Dealer fix. I said no thanks, thinking about dropping the tank if the LP ever went out again, I went ADog

 

[gary johnson]

Don't know what type of sealing washers go with your fuel lines, but stock banjo fittings need to have new copper washers installed whenever you remove them. Make sure they are clean and no engine grit on the surfaces when you install them.

 

[wrichards]

thanks gary, i have not looked at it since the swap in january, where are the suspect banjo bolt washers located??

 

[gary johnson]

If you are still stock, there are several banjo fuel fittings. They are round and bulbous looking on the fuel lines. There are 2 on top of your fuel filter, just follow the fuel lines. On the left goes to the P pump, there is one there. The right line off the filter goes to a double connection, where one fuel line comes from the lift pump into the filter and the other line goes up on top of the engine and I think there is a banjo fitting there also, for return fuel from the P pump and injectors. One more for the overflow valve, located on top of the P pump just below #1 delivery valve. By the way, might be agood idea to replace that considering the milage you have. The connection to the lift pump might need looking at if you have replaced the pump, it could be loose or not sealed correctly, if you suspect air. There are 2 copper washers for each banjo. Hope this helps

 

[GAmes]

Just an FYI, since I changed my filter today. After removing the bleed bolt it took 160 pumps of the plunger to get solid fuel from the hole. After putting the bolt back in about another 25 to hear the OFV squeak. Started on the first turn. FWIW, I have never replaced the banjo seals on any of the fittings except the OFV, and then only if I had a couple on hand. My filter head has been removed and installed completely from the truck at least six times. The IP six or seven times also. Somewhere in the vacinity of 60 filter changes necessitating the removal of the bleed bolt.