4BT VE pump fuel/starting issue

181 Views 5 Replies 4 Participants Last post by Blackduck596, 2 d ago

mpiro

Discussion Starter · 5 d ago

So issue with my 4bt VE pump swap in my 58 ford f100. No matter what I do I’m getting air out of the return line and at the injectors.

Engine has been rebuilt with new everything besides the crank and cam. VE pump was just rebuilt and put back in. It has new lines, injectors, whole new head, everything.
Here’s what I’ve been doing:

1. Hand primed and cracked each injector while rolling the engine over by hand, priming until I saw clean fuel.

2. Tried to start and no dice, just cranks and cranks.

3. Pulled the fuel feed and return lines from the tank and tried to run it out of a 5 gallon can. No dice, still air on the return out fitting.

4. Bought a brake bleeder system from harbor freight to hook to the return and pull a vacuum through the motor and get the air out. I can get clear fuel but then go to start it and no dice.

I’m at Witt’s end with it. Extremely frustrated because I just had the pump rebuilt and thought it was that. I do have a theory though and I want some opinions. The T-Fitting that comes after the injector returns, that then splits to the return to the pump and return to the tank, could that be my culprit? My thought is if it’s leaking say on the feed back to the pump, then I’m introducing air there and then still get bubbles.

Any help would be EXTREMELY grateful

Save

1 - 6 of 6 Posts

Blackduck596

· #2 · 4 d ago (Edited)

Did you have the can above the lift pump? Which style of lift pump are you using?
To draw air in it has to be on the suction side of the pump if only using the lift pump and not cranking.
When cranking dodgy injectors can pass pressure back into the fuel system.
Next check for the lack of start would be the FSS, they will pass fuel with the lines cracked but not when there is pressure in the lines. After that need to check the timing.
Last thought, do you have the inlet and discharge banjo bolts in the right place? The restricted one goes in the discharge.

Save

BobS

· #3 · 4 d ago

You stated "1. Hand primed and cracked each injector while rolling the engine over by hand, priming until I saw clean fuel."

You need to be cranking the engine with the starter. You should see a "stream" of fuel exiting at the injector connection nut. Anything less will not start.

Save

Reactions: 1

Blackduck596

· #4 · 3 d ago

I have had no problems just bleeding with the lift pump and rolling the engine over to get fuel to all injectors.
Did this when I first installed the engine and it fired straight up which I did not want as It had sat for a few years and wanted the oil pressure to come up first.

Save

Someoldguy

· #5 · 2 d ago

mpiro said:
So issue with my 4bt VE pump swap in my 58 ford f100. No matter what I do I’m getting air out of the return line and at the injectors.

Engine has been rebuilt with new everything besides the crank and cam. VE pump was just rebuilt and put back in. It has new lines, injectors, whole new head, everything.
Here’s what I’ve been doing:

1. Hand primed and cracked each injector while rolling the engine over by hand, priming until I saw clean fuel.

2. Tried to start and no dice, just cranks and cranks.

3. Pulled the fuel feed and return lines from the tank and tried to run it out of a 5 gallon can. No dice, still air on the return out fitting.

4. Bought a brake bleeder system from harbor freight to hook to the return and pull a vacuum through the motor and get the air out. I can get clear fuel but then go to start it and no dice.

I’m at Witt’s end with it. Extremely frustrated because I just had the pump rebuilt and thought it was that. I do have a theory though and I want some opinions. The T-Fitting that comes after the injector returns, that then splits to the return to the pump and return to the tank, could that be my culprit? My thought is if it’s leaking say on the feed back to the pump, then I’m introducing air there and then still get bubbles.

Any help would be EXTREMELY grateful

I am facing the same thing... mine runs ( it took a bit of work) but if it sits... it gets rough..... I have come to the conclusion the manual fuel pump if bad even though it is brand new... But I'm not working on it for a while.. I'm going to an in line electric... but be careful on the fuel pressure... From what i read the fuel pressure at the lift pump should be no more than 10#... If you over pressure you may get all sorts of issues in the injector pump... the new style plunger types put out way too much pressure.. ( Mine is an old diaphragm pump)... Back pressure test your system from the IP to the tank... because you can have air leaks with no fuel leak... was the fuel at the injectors under pressure?... it shouldn't just come out it should spray ... crack the lines a bit more... and see if you are getting pressure not just fuel.. hopes this helps..

Save

Blackduck596

· #6 · 2 d ago

New style piston pumps have too much pressure if you get the wrong one. There are pumps setup for the Ve IP.
Nothing wrong at all with the standard lift pump unless you have gone crazy on the mods. If gets rough then there is a leak in the system allowing air in. Mine just sat for 3 months in the panel shop and they got it going without any issues.

Save

1 - 6 of 6 Posts

Top Contributors this Month