i intalled a new fuel water seperator in my 86 F250 6.9L IDI with banks turbo, after i installed it i now have a problem that when i give it full throttle it cuts out then takes a while to start back up like its pumping fuel back up into the motor, i was told i have air in the fuel. any ideas would help thank you

 

Did you put a aftermarket unit on the truck, a new OEM replacement, or a new used replacement? The original type separators are famous for leaking air, and most people bypass this unit and just run a filter, and sometimes use a aftermarket separator with less problems.

In your case for a test, I think I would bypass it temporarily and see if the problem goes away. That would at least point you to the problem possibly.

 

i used an aftermarket one from napa it justhas a drain plug.

 

i went to bypass the seperator and found that the seal on the injection pump side fuel line has an oring seal that is pretty wore out so im going to replace the o ring and see what happens

 

so i bypased the fuel water seperator and can see alot of air coming into the filter i put on and it still cuts out when i give it a little extra fuel

 

Do you have lots of fuel in the tanks? You know these trucks are famous for the pickup in the tank breaking off. It looks like a big plastic shower head, and when it breaks off, you have to keep lots of fuel in the tank or it runs out.

I would also inspect your fuel lines. They may have rusted and have a pinhole, letting air come into the line. Another experiment would be to get a diesel fuel can(if you have one for a tractor or something), and run a rubber line into it and hook it up to the fuel pump and see if the problem goes away.

 

i stoped woring on it but im going to fill the tanks tomorrow morning but the one im on should be pretty full... in the morning the truck usually takes a little longer to crank up cus normally it take just a second making me think fuel is backing out the line, i have fixed a leak befor and put the truck up on the hoist at work and got a good look at the fuel lines there in good shap no rusting

 

filled up both tanks and it seems to be better but it is still getting air iinto the the filter i out on, my next idea was to move the filter below the fuel pump to see if the air is coming befor it or after