Fuel delivery problems 351w - I'm STUMPED!

[MartyG]

I'm have fuel delivery problems...driving me crazy.
Just does not fill that in line filter next to the carb.

So far I have gone through and replaced the following:
Replaced the mechanical fuel pump...twice...now it's pushing 6-9psi.
Replaced the eccentric
New Fuel lines
New rear main and Aux. Tanks (kept orig. pickups for both)Checked and made sure both tanks are vented.
Rebuilt the Holley 4 barrel carb

We put an electric pump on it to assit to the mechanical...filled the fiter fine.

I would rather keep a mechanical pump on it.

I have two 30+ Ford mechanics helping me with this and are pretty stumped.
One said that this is a prob with some Fords...the pumps just don't pull enough fuel. They suggest next step would be two electrical assists from each tank.
Anyone else had this problem? Any suggestions?

 

[73azbronco]

so running a line from the mechanical pump to a gage you have how much pressure?

6-9psi but not pushing fuel to carb? Does not make sense, have you checked the lines for obstructions, blown them out?


it sounds like you have fuel, it's just not getting into the carb, maybe thats clogged up?

if your free flowing fuel out of the pump, you have fuel. you need to check the carb.

does that inlin filter have a one way checkball/valve?

 

[70_Steve]

Or is the engine running just fine, and you're stumped as to why the fuel filter isn't full?

Maybe you have a leak on the suction side of the mechanical fuel pump and it's sucking a couple air bubbles. When you install the electric pusher pump, no air can get in the line.

 

[broncnaz]

The filter doesnt have to be full. As was asked how does the engine run? If it runs fine forget about it.

 

[73azbronco]

tripple ditto, if it runs, run it, you will usually see some air in an inline glass filter, least I have.

 

[SDlivin]

The filter doesnt have to be full. As was asked how does the engine run? If it runs fine forget about it.

X2, I have an electric fuel pump, with an inline filter just before it. Filter does not fill up completely, in fact only fills half way, just enough to fill the inlet and outlet of the filter and that is it. did some mild wheeling and did not have any problems.

Shouldn't be a problem as long as it runs fine.

 

[MartyG]

X2, I have an electric fuel pump, with an inline filter just before it. Filter does not fill up completely, in fact only fills half way, just enough to fill the inlet and outlet of the filter and that is it. did some mild wheeling and did not have any problems.

Shouldn't be a problem as long as it runs fine.

Hmmm...well, it does run fine...filter runs almost completely empty to half full sometimes.

As I mentioned though, no need to blow the lines out...they are all new.
This was the prob before I replaced them....engine was dying from lack of fuel.

Guess I'll run it and see. Thanks guys...

 

[Rustytruck]

You could be sucking air in the fuel selector valve under the drivers seat. If you take that valve apart there is a replaceable O-ring for the shaft. There is also a fuel pump specification on how much fuel the pump puts out not just pressure. You have to look it up in a service manual and crank the engine and pump the fuel into a measured container. You would be shocked at how much air is sucked in through hose fittings. I have never seen so many hose connections as there are on a smog era Bronco in my case its worse as I have 3 tanks and all the vent connections.

 

[garberz]

If it runs fine, then get an inline filter that you can't see through.

 

[Steve83]

%) ;D

DING!DING!DING!DING!DING!DING!DING!

No more calls, please: we have a winner!!!

 

[MartyG]

Thats pretty funny guys.%)

 

[bludorbronc]

i bet if you were to make the lines so the filter was vertical then it would fill all the way with no air being traped inside.

 

[MartyG]

To be clear...the filter is only showing 1/4 full, if that. But...it seems to be running fine so we'll see.

 

[Steve83]

To be clear...the filter is only showing 1/4 full, if that.

Disconnect its output hose from the carb and watch the fuel running into a jar. It's sort of like a gas tank being 1/4 full - you still get fuel out of it because the pickup is low in the tank. Same with the filter - the air is trapped, but that doesn't stop fuel from going through.