258 fuel pressure

RICHARD WM NEWKIRK

MEMBER
1976 JEEP CJ7
4.0L
6 CYL
4WD
MANUAL
200,000 MILES

I just installed a clifford performance dual weber setup, I'm at 4 lbs of fuel but still getting the damn fuel starvation sense under load. Bucking popping etc. Anyone know what the fuel pressure SHOULD be? New low pressure fuel pump but I am thinking higher. With the regulator set at 4.5 under load the jeep runs but if you floor it. Bam. Thoughts?

Saturday, August 27th, 2016 AT 4:19 PM

3 Replies

CJ MEDEVAC

MECHANIC
11,005 POSTS

Dis is a 258?

Mechanical pump?

Are you able to see the fuel pressure to each carb while it's running?

The Medic

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Saturday, August 27th, 2016 AT 5:03 PM

RICHARD WM NEWKIRK

MEMBER
2 POSTS

Showing 4.5 under load at the regulator. Electric pump. Thinking that since it is a dual carb setup. The 4.5 may lag behind given the draw. Does that make sense? Meaning should I bump up to 6 at the regulator since it splits off to two fuel lines?

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Saturday, August 27th, 2016 AT 5:18 PM

CJ MEDEVAC

MECHANIC
11,005 POSTS

I was a plumber a few years back. Volume and Pressure are two different animals, people tend to wanna increase their water pressure in an attempt to overcome galvanized piping being nearly internally closed off due to being almost rusted shut, or to overcome their improperly sized piping (copper/ pex/ pvc).

Do you still have a return line outta your fuel filter?

This would be my 1st test/ attempted fix

A separate regulator for each carb might give you more volume, just jacking up the pressure on just one regulator (feeding 2 carbs), may not make up for decreased volume trying to push thru the regulator's internals.

I bet the mechanical pump woulda provided enough fuel! But I'm guessing!

If you are experimenting, maybe increase the fuel line size from the pump on.

I have a Holley 390 on mine (pic above)

Your turn

The Medic

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