I'll take the hose off and check again.  Blowing through the hoses and tubing is a part of my plumbing routine.  The line along the frame is away from heat.  Once it gets close to the engine it is probably 1" - 3."  The warmest part is at my fuel block off but I can hold onto it anywhere and not get burned.

I installed the pump at the same time as the new engine about 3 months ago.  All lines from the pump to the carb were new.  The stock tank was being used.  The same sort of thing was happening.  I did some trouble shooting and narrowed it down to the pump or tank.  I did not have 3 gauges installed at this point.

Over the past few weeks I installed a fuel cell to eliminate the stock fuel tank from the equation.  I've been wanting to install a fuel cell anyway.  Now everything from the fuel cell to the flex line is new.  Still the same problem.

These two systems have used the same plumbing from the flex line to the carb.  It is the plumbing between the tanks and flex line that has changed.  The parts that are the same among the systems are the fuel pump, regulator, and all plumbing from and including the flex line, to the carburetor. 

I ran out to remove the hose.  I can blow through it easily with no indication of a blockage no matter how hard I blow, in either direction. 

Oh, It will die if it idles with the pressure at 0psi but it will run if I give it gas.  This doesn't make much sense to me.  The only thing I can think of going on here is that when it runs at about 600rpm the alternator isn't doing much charging and the pump is running slower.  When I give it gas the extra voltage speeds up the pump which kicks up the pressure enough to keep it running.  I haven't noticed any visual change in pressure from 12.8volts to 14.2volts, however.

Lawrenceville, GA

Hello, I got in your post in the middle so if this has already been covered just ignore it. Have you checked the pump for VOLUME instead of pressure. Either tap off the existing fuel line (the rubber part ) or just disconnect the line and put it into a gas can. Power the system and check the fill rate. It can not be that hard so try to start over and do not assume ANYTHING. Let us know. Pete

Charlie:

We gotta get that truck to Columbus.  Here's what I see in my mind, and I know you have checked the lines.  Your pump can charge the entire system with 5 psi all the way to the carb when the engine is not running.  Now, when you start the engine, the pump outlet gauge continues to show 5 psi, which should be enough to keep it running.  After it runs a couple minutes, the pressure starts to drop at both sides of the regulator.  Why?  The needle valve in the carb opened, so that part of the line is now open at one end, so it can't get pressurized to 5psi.  Why can't it get pressurized to fill the carburetor and close the needle valve again?  Because somehow there is not enough volume of fuel getting through from the pump to the regulator.  The flow test mentioned above should show that.  If enough flow was getting to the regulator, then those gauges would show 5psi even when the float bowl was empty if the blockage was between the regulator and the carb.  Hope this is not too confusing.

John

John - "The Hoosier Hurricane"

That's a good idea.  I can check the flow rate before I remove the fuel cell to install the filler pieces.

I used the pump to empty the old tank.  I didn't time it but it was absolutely adequate for idling.  It's rated at 97gph which is 1.62gpm.  The can I was using is 2gal.  The time it took seemed about right.  I'll be sure to time it next time.  I'm going to go ahead and get another pump on order.  It's the only thing I haven't been able to bypass.  I hate to just throw parts at it but I feel like I've checked everything I can.

I spoke with Holley tech again today.  They did better but still not impressive.  They seem to think that it is possible that the pump is showing 5psi at the outlet but it is too weak to maintain 5 psi farther away from the outlet.  It sure doesn't seem common though.

Lawrenceville, GA

Hi Charlie; One of my dad's old tricks for checking fuel delirvery was to pull the coil wire, take of the fuel line at the carb, put a rubber hose into a coke bottle,(smaller bottle not those big ones like we have now) crank the engine 6 times and the bottle should be just about full.  Dad was a mechanic until he retired in1971.  Worth a try!!   Also I would change the rubber flex lines just for grines, at my shop had an A/C hose that was breaking down inside causing a flap inside that would stop the flow after a while.   Hope this helps.  Thanks everyone Eddie

Eddie

Lake Forest, Ca. 92630

Charlie, where do you live? Chuck in NH

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I can change the hose.  I'll...  Actually, it can't be the hose.  I took that hose out of the equation already.  I wanted to bypass my fuel pump block off to rule it out as a heat source.  To do that,  I installed a niple before the rubber flex hose to install a rubber line between the regulator and frame rail fitting.  The same problem still existed.  The only thing that remains is the fuel pump.  I guess I can tripple check the hard lines.

Chuck, I'm in Norcross, GA - slightly NE of Atlanta.

John's explaination is clear to me.  If I've ruled everything else out and it's not getting enough volume it must be the pump.

Lawrenceville, GA

Charlie:

One more thing.  Have you checked the screen in the Holley pump?  Since you ran it on an old tank, it could be full of junk.  However, I don't see how it could maintain pressure when the pressure drops of at the regulator with the screen clogged.

John

John - "The Hoosier Hurricane"

I saw the screen when I changed out the brass nipple to the -6AN fitting. It looked clean. I had a filter before the pump too. The filter had nothing visible in it. The tank is surprisingly clean.



I ran to Summit last night and picked up a new pump. I'm going to wire everything properly so that inadequate electrical connections are ruled out. I'm going to remove all of the line and use some mig welding wire to make sure nothing is in them. Up to this point I've just been blowing air through. Maybe this way I'll be able to feel something if there's a significant blockage. If it doesn't get too late I'll start it up and see if this helps. Apparantly the neighbors are starting to complain about my working on the truck.

You know what I think would be cool? A neighborhood where you are required to own a car that is 30 years or more old and at least one work in progress in the driveway and perhaps new cars must be kept out of sight in the garage! I'm too young to be getting tired of these ignorant people and rediculous laws that prevent good people like you all and I from doing something legitimate for fun. I'm not out at 11:00 at night reving it to 6000rpm and doing burn outs in my driveway! Alright, well that's my venting.


Lawrenceville, GA

Well, I don't know what's going on.  The lines and filters are clean.  I've bypassed everything there is to bypass.  I installed the new pump and the same thing is going on.  It is a long shot that two pumps are bad.  There can't be any restriction.  All lines are 3/8 or 6AN (which is 3/8, 6AN is 6/16) which should be able to provide a more than adequate fuel supply for the power level of my engine.

This is my first time running a pressure gauge and regulator.  I am assuming bythe replies of many of you that pressure that starts where I want and drops off gradualy is not normal.  It is not logical in my mind.  So hopefully I'm not trying to fix a problem that doesn't exist.  For about 5 or 10 minutes the pressure stays steady.  Then it starts to drop off slowly.  After 15 - 20 I shut off the engine and the gauges are very close to 0.

Can a problem with the floats or needles cause this?  The carburetor is the only part of the fuel system that I haven't done any kind of test or check concerning the fuel pressure issue.

Lawrenceville, GA