EFI diagnosis/ engine stumbles at 1/2 tank .

[mbaird]

Does this happen even if the car is being driven smoothly on level road with no motion that would cause fuel slosh? If so and it's happening earlier, it's not likely a cavitation issue. You should pull the sending unit and pump and check the lines for leaks with air pressure and soapy water.

You can order submersible fuel line from these guys. Just tell them the size and length.

http://[URL]https://www.harmonracingcells.com/

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On a related note, most of the so called baffled tanks they sell are not very effective at feeding air free fuel when below 1/3 to 1/4 tank. Using a surge tank system with a stock tank is vastly more effective when driving road course type roads, as any air sucked in from the tank is constantly purged from the surge tank prior to being fed to the engine.

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Yes , it will happen cruising at light throttle . Used to be only when tank reached 1/2 . Now since new pump install it happens sooner . I did look over pickup for leaks but may have missed something.

 

[plymouth4onthefloor]

i had a leaky catch tank inside the fuel cell, when fuel level was low, the return line foamed the fuel inside the catch tank! You will not see a fuel presure drop, this is a really piss off failure. I saw it only with a camera

 

[mbaird]

i had a leaky catch tank inside the fuel cell, when fuel level was low, the return line foamed the fuel inside the catch tank! You will not see a fuel presure drop, this is a really piss off failure. I saw it only with a camera

Huh …. That is good info . Thanks !
I restored this truck and pulled the tank to clean it but I don’t recall if I saw a catch can in there ? I haven’t had time to do much with it since initial post but I will research it . I was also thinking I should test the delivery volume . Maybe the new fuel filter is already clogged?