I have two of those Holley pumps. A red one on the rear tank on my dually, and a blue marine version on my cuddly cabin. I’ve had trouble with both of them. The one in my truck acts similar to what yours is doing. I haven’t diagnosed it yet, I’ll likely just ditch it. The one in my boat was brand new and locked up after sitting over the winter. When I disassembled it, it looked like it had been in a lake for years. All corroded up. The ethanol destroys them, they do not stand up to it well. I do think parts are available to service them. When the one on my truck acts up, I can tap on it and it will usually run. I suspect it has internal corrosion like the marine one did.
I had a electric fuel pump failure in August 2021 and I couldn't find any replacement parts then. Quickfuel sells an end bell that looks like it should work but will not. For more info check out my thread on this situation.
I had a fuel pump failure yesterday. I was on my way to Advanced Auto where I did work to recycle some oil when it failed. First I tested by connecting power directly to the pump, all I got was sparks when I made the connection. Pump did not turn over. I pulled it apart to see what went wrong...
Not trying to talk down or criticize your choice rbsWelder. Just didn't want others to think that would work for everyone.
Using the pump below as an example
That would not flow enough for any engines over a couple hundred horsepower. The pump flow rate 38 gph and that's free flow, it's not pumping against any pressure.
Fuel flow at a pressure of 5 psi will cut the free flow rate more than 1/2. The Holley pump below is rated at 97 GPH, but at 5 psi its only flowing 44 gph. Therefore the flow rate of the Advance Auto pump would be 17 GPH.
Below is the Holley pump and it's flow at different pressures.
Using the Fuellabs calculator, 17gph would support about 225 HP.
I have a relay before the pump. I tried two new relay's same problem. Then I bypassed the relay, same problem. I haven't given up, just looking for other options. I put 5000 mile on without any issues. Then this started. I let the T idle about ten minutes and you can see the psi slowly drop on the gage. If I turn the regulator psi up the gage moves but starts slowly dropping again. I have the psi set at 6 psi. Not sure if that is to high for the carbs. The carbs are Rochester 2G. You can see the setup in my avatar picture. I'm waiting for the weather to warm up then its off the the races.
You said you replaced the filter just before the carb, but what kind of filter is before the pump, how could you tell it was clean?
Is there a chance you have one or both filters installed backwards? Most have a flow direction indicated on the body?
You do have at least a 5/16" fuel all the way from tank to carb?
To test if the fuel flow is adequate, pull the fuel line off the carb. Turn the pump on and let the fuel flow into a container of know size. The Holley Red pump is rated at 97 gph/free flow. Measure the amount at one minute. In your container should be something close to 1.6 gallons.
97 / 60 = 1.6 gallons per minute. You have two filters in line with the pump so it's not exactly free flow.
It would also be interesting to see what the flow is coming directly out of the pump and compare the two flow rates.
BTW, are you still having the problem with the engine dying?
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Sounds like you replaced everything except the carb. Hmmm...since I don't have to do the work, why not check the float and needle valve. A leaky float might do what you are experiencing.
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