I can live with that.  It seems to be the best explaination.


Lawrenceville, GA

Charlie,

          Another issue, when the fuel pressure gages get warm the readings will drop. I found that out on my Windsor powered Ranger. I am not certain why a bourdain tube would get stiffer with temperature, but it did. If you have that much volume, and the truck runs OK, then quit worrying and drive it.  

Frank/Rebop

Bristol, In ( by Elkhart) 

John,  I did a fuel test.  It took 1m16s to empty 1.75 to 2 gallons.  This works out between 82.68 and 94.49gph.  The measurement was taken at the outlet of the pressure regulator with about 3 feet of hose.  I didn't have time to do a flow test after the pressure drops.  I didn't have a container large enough to do a longer test.  Plus I was at a friends house and I needed to mke sure I had enough gas to get home.  It got too late to do another test once the pressure had dropped.  I had nothing to use to simulate a needle seat.  The pressure with the mechanical pump behaves in the same way, with the electric bypassed.  There is no vacuum on the inlet side of the mechanical pump.

Pete, I appreciate your help with this.  I don't know if what I'm experiencing is a problem.  I have no prior experience with inline pressure gauges, regulators, and what is normal.  I haven't been told by anyone that what I am experiencing is or is not normal.  Apparently the stalling issue is related to something else.  It hasn't happened again on the past few trips around the block and to the store.  The engine runs great cruising, getting on it and so on. 

I measured the manifold vacuum at 13"hg, idling at about 700rpm.  I ran the engine with a gravity feed for 6 minutes with no problems.

Lawrenceville, GA

Charlie; Going back and reading ALL your post to me is like watching a soap opera on day time TV. I do not wish to be unkind but you seem fixated on the PSI of your fuel pump and are trying everything you or anyone else can think of to "FIX" it. You say it can`t be the carburator because the Edelbrock tech guy said it wasn`t. I want you to step back and count to 10. RESTATE the actual problem. Describe the symptoms. What is the manifold vacume while the engine IS RUNNING? Add a temporary gas supply from a small container to the carburator NO FUEL PRESSURE GAUGE and tell us what happens. Do not assume ANYTHING. A lot of guys want to help. Good luck. Pete

Charlie:

Have you done a 2 or 3 minute flow test yet?  I tested the system on my race car a few weeks ago, had a line on the line that I disconnected from the carb, with a 1/8" hole in a fitting.  It maintained 6 psi while pumping gas through that orifice.  That is about the size of the needle and seat.  Holley blue pump.  You said the mechanical pump did the same thing.  Was the electric pump turned off at the time?  If so, the mechanical can probably not draw fuel through the shut off electric.  Do you have a vacuum gauge that you can tee into the inlet line to the mechanical pump?  If the line is open all the way to the tank (electric pump needs to be removed or bypassed), you will see very little, if any vacuum.  If the line is stopped up, you will read full pump vacuum, probably around 10".

John

John - "The Hoosier Hurricane"

It's doing the same thing with the mechanical pump.  I just don't know what's happening.  The only thing that has been consistent with every test is the carburetor.  Can it be getting too hot and just not showing the standard symptoms?  Maybe vapor lock is occuring at the carb inlet?  It was clean when I checked the float levels.  Nothing can be blocking the flow.  I wonder if if I need a higher pressure pump for some reason?

It seems to be running fine.  A small amount of pressure loss is expected in the case of the electric pump because it is so far from the engine but it shouldn't for any reason drop to 0.  Pressure loss with the mechanical pump should not be measurable with my instruments because it is so close.

At this point, unless some miracle occurs, the truck isn't going to be at Columbus.  0 psi means something is wrong.  I'm not interested in breaking down in the middle of a 600 mile trip.

This is why you should use the absolute minimum number of gauges necessary to drive.  If you don't know there's a problem, there isn't one!

Lawrenceville, GA

I removed the filter.  Still the same thing.

I've taken a couple trips around the block.  It's been idling well and hasn't tried to die.  I have a mechanical pump that I'll install to see if it changes anything.

Lawrenceville, GA

I see you still having problem with your electric pump setup.



I had a similar problem but with a different pump and regulator. Heres what happened and what I did, I just fixed it yesterday.



I have an Accel 43Gph 45 PSI in line pump, a mallory return style regulator. I hooked it up with a filter before the pump, It will draw constant fuel when the tank is full, after it gets to about 3/4 full it stops supplying fuel, the pump was still running. next I took of the filter thinking it was the problem, (it was but that wasnt the only problem I had at that point) and put it after the pump, it would draw fuel at almost 1/4 left. but soon after it stopped.

I took off the filter, and what I saw was rusty mucky gas with grit coming out, in less then 4 hours of run time, the fuel filter was completely, i mean completely clogged. Took the tank off, dran the gas and the gunk, then realized I bent the pick up tube too far down, its too close to the bottom of the tank, so I fixed that.



put everything back together, this time filter before the pump again. clean gas, but after a while (about 3/4 tank) it will stop picking up fuel again. I had installed the pump above the fuel tank , thinking that was the problem, I made a bracket and move the fuel pump at the level of the bottom of the tank. well I got one of those fram clear plastic filter for use before the pump, i can see its not filling the filter up and drawing air. so I remove it again, and put a metal one after the pump, since all the gunk is gone, it should be ok. and it is, now it runs fine even below full tank.



I had the same problem with my carter 12psi carb electric fuel pump with the filter before the pump. but i didnt try it without filter



so If you have that fuel cell in, it should be clean right? then try it without a filter and see if its the cause of the problem.



hope this help

The voltage is good when the pressure is low.  I ran rubber line from the pump outlet, directly to the carb inlet with a gauge just before the carb.  I ran the line along the passenger side, completely avoiding the exhaust and allowing for the shortest possible length of hose running across the engine.  The same thing is happening.  I just can't understand what's going on.

I'm going to try the old, reliable mechanical pump tomorrow. 

Lawrenceville, GA

I checked the carb. The float levels were slightly off but not enough to cause problems.

You know what else I haven't done? I haven't checked the pump voltage when the pressure has dropped. It could be the switch. I have a .6 volt drop between the + side of the switch and the - side of the switch with everything cool. This is taken at the spade terminals of the switch. I don't know if that's what should be happening. I think I'll check that first thing when I get home this evening. If the switch is faulty and dropping the voltage several volts, the pump might maintain pressure at the outlet but not supply the volume to maintain pressure 15 feet away. Let's hope so.


Lawrenceville, GA