fuel pressiure problem 4.0 swap

bada$$broncoII1990 · Dec 17, 2010

Ok here is the deal....I got my 4.0 swap done in my wifes b2. It ran awsome until she stopped at the gas station. She shut it off and went to start it back up when she was done pumping gas. She went to start it up and it stalled right out on her. And we have has this consistent problem ever since. I put a new fuel pump in x2. I have replaced the strainer....fuel filter and pressure regulator, check to see if the intertia switch tripped it wasn't. I can only get 5 psi at the rail....any ideas. It will start.....and idle for 10 sec than shuts off.

n_grimm · Dec 17, 2010

Do you have just one pump, the one in the tank? Does the pump run when you first turn the key on and also when you are cranking it over, and does it continue to run once the engine is started?

bada$$broncoII1990 · Dec 17, 2010

n_grimm said:
Do you have just one pump, the one in the tank? Does the pump run when you first turn the key on and also when you are cranking it over, and does it continue to run once the engine is started?

Yes just the one pump. It primes...and runs for the short while the engine runs. And the pump continues to run for about 3-5 sec after the engine dies

bada$$broncoII1990 · Dec 17, 2010

One note I have been trying to use the exploder pump on the b2 housing....I'm wondering if it's just not sittting in there tight enough and fuel is just pumping right back into the tank instead of the lines. Oh and the b2 is a 1990 and the harness and ecu is 1990 ranger

slow96gt · Dec 17, 2010

i was having the same problem but on my ranger, my truck was a 2.9 with the dual pumps, what i did was take the pump out of the tank and put a draw straw on ( apieceof rubber hose the the stock pumpwas) and took the one off the frame rail and bought a 90 f150 5.0 inlinepump, it bolts right into the stock location all the wires are the same and the fuel line disconnect were the same and i havent had a problem since

n_grimm · Dec 17, 2010

If you mean the pump is leaking into the tank, I've had that happen before. When I replaced my in tank pump, I used a new hose and clamped it instead of the original setup. I hope you have an access hole so you don't have to drop the tank again

RUTH · Dec 18, 2010

keep this thread going... i have been fighting this same issue for about 4 months... did the 4.0 swap and ran great for about a week... i have put all new plugs, wires fuel pump, o2 sensors fuel regulator, computer and a few other things, runs great for about 20 min, then just wants to die all the time...and im lost with it

slow96gt · Dec 18, 2010

i had to get rid of my in-take pump, my truck would idle all day and even rev up, but as soon as you would but it in gear it wasnt getting enough fuel, so why not upgrade, you can get a wal bro 255 for around 150 dollars just my .02 cents

trail B2 · Dec 19, 2010

I have a newer pump in mine and it works good I did replace the hose with new clamps.I think this area is responsible for that start then die thing that happens.I didn't notice you saying that you replaced both filters one cartridge mid length and one inline right before it goes up to the motor.

fuel pressiure problem 4.0 swap

bada$$broncoII1990

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