Archived Need tips on Bleeding fuel system -12 valve

[94ram]

Need tips on Bleeding fuel system -94 12 valve



Had to pull fuel tank to remove trash, now I have pumped and pumped on lift pump primer, but can't get her to fire,



Any Help out there?



thanks,

kB

 

[Joe G.]

First of all, it takes a LOT of pumps on the button. One way to get fuel up to the business end is to open the bleed screw on the fuel filter output side. Then use a rag or something to put around an air hose. Put air in the tank to force fuel through the system.

 

[EKlem]

Pressurizing the tank definitely makes it easier. Just make sure that you regulate it to like 15 psi or so. If you are going to do it with the hand primer, it may help to remove the fuel filter rather than just opening the bleed screw to get less resistance. Good luck.

 

[94ram]

Thanks, I"ll try a little air pressure,

Pumping that lift pump doesn't feel as if it doing anything, even with the engine cranked to different positions.

Can that pump plunger button be bad or leaking?



thanks,

KB

 

[Joe G.]

The button is probably ok. It will take a couple of hundred pushes to get fuel from the tank to the filter outlet.

 

[SDrake]

I used a vacuum cleaner hose hooked to the blow side to pressurize the tank and out comes fuel at the filter. I thought, how easy could this be.

 

[Cummins360]

Thats a great idea, the vacuum cleaner hose lol.

 

[bighammer]

I had a tough time trying to get my 94 started after a fuel filter change. I pumped the primer (hearing fuel movement) but still couldn't get it to go. I finally realized that the pump was just sloshing fuel back & forth-- A check valve in the lift pump had died so once I replaced the filter and introduced air, it wasn't pumping anything.

The truck had been running OK before, but maybe not quite its usual power. (that's why I changed the filter)

 

[94ram]

Hi, I got her primed and running, I pumped that plunger till I got a blister on my thumb.



Then tried a little compressed air in tank, about 20 psi and out came the fuel.



Thanks TDR!



P. S. , now the bad thing is I have an injector pump problem, very little fuel getting pumped to two injectors, even after an hour of bleeding.



Any ideas?



thanks,

 

[EKlem]

Do you have any way of checking your fuel pressure? If you couldn't get it to prime with the lift pump, that can be a sign of a bad lift pump. Have you cracked the injector lines at the injectors and waited for wetness?

 

[Joe G.]

The lift pump is the least likely thing to cause a problem in priming. It way more likely to be an air leak.

 

[94ram]

If I crack the injectors, I have 4 that are working good, no air bubbles, and engine slows down.



Two of the injectors pump a lot of air and some fuel, and make NO difference in the idle quality.



This is after an hour of letting them bleed at injector/ connector line.



Where do I go Now???



thanks.