Lost fuel pressure!

Dean Lampe · 10-21-07, 07:39 PM

My fuel pump is a holley red pump and it will no longer pumps fuel. When I disconnect the "out" Line to the carbs and blow through it, I can hear the fuel bubbling in the tank. It feels like there is air coming out when the pump is running. It just won't pick up any fuel. I have plenty of fuel in the tank. Any ideas? Do you need more information?

Bill Musarra · 10-21-07, 08:09 PM

Dean,
Do you have a pickup line in the tank with a filter on the end. Could be clogged. If you have used lines off ebay they could have junk in them that has clogged the prefilter. Also there may be debris that is keeping the impeller from working. If the pump ran a while with no fuel in it, it could have dmaged the pump itself???? I would advise pulling the lines and inspecting along with the filters.

Bill

Rob · 10-21-07, 08:11 PM

Hey Dean,
Try swapping pumps from side to side. This will eliminate any plumbing / pick up potential. Then, if it follows the pump. The answer is easy....

Big-Foot · 10-22-07, 08:43 AM

Most vane type pumps will not be long lived in a position where they have to suck the fuel up-hill. The manufacturers all indicate that the preferred mounting position is no higher than the top of the fuel tank/cell..
The old SW pumps were diaphragm pumps and would pull fuel straight up 30 feet. I don't know if your pump has failed but it sounds like it's check-valve may have some crud in it or the vanes are just too fried to seal up anymore..

Dean Lampe · 10-22-07, 11:11 AM

Is the Holley Red pump a Vane or Diaphragm pump?

Big-Foot · 10-22-07, 11:46 AM

Hi,

The red pump is a VANE type pump. You may have better service life out of a Gearotor type pump and most certainly would from a Diaphragm design pump.

More info here;

Holley Fuel pumps
http://www.holley.com/data/TechServi...ech%20Info.pdf

Holley PDF - Gearotor
http://www.holley.com/data/Products/.../199R10367.pdf

Facet Dura-Lift pump
http://www.facet-purolator.com/mcl/m...lift_sheet.pdf

I'll be using a pair of Facets on mine..

Hope this helps...

Rob · 10-22-07, 12:12 PM

Randy,
I don't disagree with what you're saying from a component design/theoretical perspective. However, I will say, I have run the Holley pumps in this manner for years, and have not had a failure yet. And, this is the first application I used the Gucci check valves (I think you too said you were running these Dean.... aren't you). So bleed back and losing prime is less likely.

Dean you may just have a bummer pump..... it happens.

Have you isolated it to the pump yet, and confirmed there is no supply tube issue?

Big-Foot · 10-22-07, 01:18 PM

Yep - many of these Vane pumps will last a long time even as a lift pump, but I think the tendancy is to make things of cheaper materials nowdays to maximize profit. I'm not so sure that they are in it for the long haul anymore. If the pumps are ever run dry for even a short period of time, they will score the inside of the diecast pump chamber and they will no longer produce the suction / pressure that they once would.. I recently took apart a carter vane type pump just to see why it was no longer working. It was placed just on top of the fuel cell. If kept primed, it would work, but as soon as it sat for an hour, it would no longer draw the fuel out of the cell..

So - if they work for you in that type of configuration, that's GREAT - if not, this may be the reason why...

Dean Lampe · 10-22-07, 08:26 PM

It is in the pump. I will bet that I probably burned it up. The way my fuel system is set up to pump into a 3 gallon swirl pot, it could run for quite some time while it was dry. The first pump is the bad pump. I didn't recognize the problem until the engine cut out when the last of the fuel in the swirl pot was burnt. Anyway, I have 3 more pumps on the shelf. I am going to switch it out on Friday. I think that will fix the problem.

Richard B. · 10-23-07, 02:26 PM

If those pumps are spinning they should be pumping fuel. I have burned up motors, but have never lost the pump itself. You said you can see air/fumes coming out with the hose disconnected and the pump running? I had a very similar situation happen and it turned out that there was a hole in the pickup line that was just large enough to keep the pump from being able to pull fuel.

Also, those pumps usually have a screen inside the body on the suction side. You have to pull the whole cover plate to see it. It is possible that the screen is plugged up.

Dean Lampe · 10-23-07, 02:32 PM

The screen was totally jammed. I took it apart and cleaned it out. The lines are OK. They don't have any air leaks. I am going to switch pumps and see what happens. That will be an easy way to see if something is not working.

Pat Buckley · 10-23-07, 03:07 PM

Probably.

Jac Mac · 10-23-07, 04:05 PM

Quote:

Originally Posted by 2124

Probably.

Jac Mac

Chuck · 10-23-07, 09:32 PM

Dean:

Just curious: do you have a filter between the fuel tank and the pump? I was planning on a filter to pick up the big chunks before the pump and a second filter between the pump and the carbs to pick up the little chunks.

Chuck

Rob · 10-23-07, 10:05 PM

Dean,
I agree with Chuck. I was just looking at some pics you had sent, and noticed it doesn't look like you have a filter before the pump. I really don't suggest this. Running particulates through the pump will certainly shorten pump life. (and clog up your inlet screens...

)

Dean Lampe · 10-23-07, 10:10 PM

You are right, I don't have a filter before the pump and it is not a good idea. It was an oversight on my part. When it goes back together it will have a filter before the first pump.