Sorry, this is a long post but I wanted to share details.

Background
1973 vette has a tired Goodwrench 350 motor in it. Car runs fine but is underpowered and leaks lots of oil. I'm building a more modern roller cam motor but the 880 block was not drilled for a manual fuel pump so I'll need an electric. Not wanting to introduce too many variables at once when the new motor goes in, I installed a Holley Red fuel pump and removed and blocked off the manual fuel pump off the current motor.

Installation details
Summit Racing Fuel Pump Relay -
- Relay is mounted close to wiper motor.
- 12V power to it comes from horn post, through the provided circuit breaker, to the relay and then to the pump.
- relay is triggered off of keyed ignition wired which gives power to the Davis DUI distributor.
- All seems to check out fine.

Holley Red pump and plumbing details -
- pump is mounted above the right muffler on inside of frame rail
- main line from fuel tank runs through a Russell filter
- Russell filter runs to inlet side of pump.
- outlet side of pump runs to another filter that has a 3rd smaller vent line
- main outlet of 2nd filter connects to the hard line which runs to the carb.
- 2nd smaller vent outlet on the 2nd filter runs to the return line to top of tank.
- I did this to prevent vapor lock and have cool fuel running through the pump all the time.
- hard return line is capped on both ends.

Problems
Apparently Holleys have a reputation for being loud. Mine was as quiet as a church mouse. On keying the ignition, I could hear the relay click but no pump noise. The pump was slightly warm to the touch so I thought it was working.

Thinking I might need to prime it, I removed the line at the carb... still, nothing.

I pulled a vacuum on the disconnected fuel line and fuel came out. Keyed the ignition...... nothing.

I next test for a bad electrical connection. 12V at the horn power post. 12V at the input side of the circuit breaker. 12V leaving the circuit breaker as long as the relay is not triggered. I lose the 12V to the relay if it is triggered by the keyed ignition!!!!! OK, maybe I have a bad circuit breaker or a short.

I next disconnected the wire leading to the pump and hook up a test light. Key the ignition and the test light comes on every time! Perfect. Looks like I'm down to either a shorted wire to the pump of the pump itself. Nothing indicates a shorted out wire (tested by looking for connectivity through the frame) so I pull the freaking BRAND NEW pump and associated plumbing.

Take off bottom of pump. Nothing is blocking the impeller but the shaft WILL NOT TURN???? I pull off the top of the pump and remove the motor. Out pops a small piece of foam. DAMN YOU HOLLEY! Reassemble and shaft turns like any electric motor.

But at least I have found the problem, right? Wrong.

Test the pump by connecting through the relay but near the relay. It instantly comes on and sounds like a fuel pump. Great... problem solved.

I reinstall everything and still bypassing the carb, key the ignition and the VERY LOUD pump fired right up. ( bypassed my true pump power line with a temp and then again with the mounted power line). In both instances, pump kicks on and pumps fuel. Great. I reconnect the line to the carb and key the ignition after looking for leaks and car fires right up!!! Looks like I'm home free!!!!

I take a test drive around neighborhood. Car seems to be running fine but then 2 blocks from the house, I can't hear the pump any more (yes, it is loud) and the car sputters and stalls, obviously starved for fuel.

After 5 minutes looking for an obvious problem and finding none, I key the ignition. Fuel pump kicks on and I drive it for 100 yards until it stalls again. I repeat this 2 more times until I get in my driveway, really, really mad.

Get car in garage. Keying the ignition a few minutes later and I've got no fuel pump sound. Post from circuit breaker to relay shows 0V which is telling me it is tripped again. I leave it alone, in disgust.

This morning, I key the ignition and the fuel pump kicks on. I don't start the car but let the pump run for 5 minutes. It never misses a beat. I go to work, angry, regretting the day I ever bought the Holley.

Questions:
1. What would you tackle next? New Carter pump? Check ALL electrical connections again? Ground on pump looks pristine and shows connectivity to frame.

2. Could the pump motor have been damaged when it was jammed by the piece of foam?

3. Could the heat off the muffler be affecting things? There is 2-3 inches of air between all and the pump and plumbing do not seem to get hot.

4. Could I be dealing with vapor lock? Having the filter AFTER the pump with the vent/return line, should, in theory prevent this but I still have a long line to the carb.

Current plan is to (i) go home, (ii) get a beer (iii) key ignition but not start car and look for a loose connection that will get the fuel pump to stop running. I will then let the car idle for a long time to get good and hot and see if that causes the pump to quick running.

I might bypass the power line and reconnect relay to pump with temp wire and go for a drive.

I only put back in 2-3 gallons of fuel in case I have to draing it again. Even if it did run out of gas, I assume the pump would still spin, right?

I do not trust the Holley as far as I can spit into the wind and will order a Carter but want to rule out any potential issues before doing so.

ANY help or suggestions anyone can offer is greatly appreciated.

Larry Hope
Houston, TX

 

I have had a Holley red pump on mine since 84 and the only problem with it was that it just wore out. I bought a new one, 4 years ago, and a rebuild kit for the old one , just in case, and so far it hasn't missed a beat.

 

Thanks. Honestly, other than people thinking they are loud, they seem to have a good reputation. That is why I bought it.

I plan to dive back into tonight starting with all electrical connections.


Any suggestions... I'm wide open.

 

I let the fuel pump run for 10 minutes with car off trying to recreate pump off issue. Checked all electrical connections. Never missed a beat.

Let car idle and revved motor off and on for 10-12 minutes. Pump started to cut on and off for 30 seconds at a time. Eventually stops pumping altogether and car stalls.

Car is warmed up. Pump is noticeable hot. Surrounding plumbing is simple warm.

Any guesses? Bad pump? Heat from muffler?

 

bad relay? swap that out before the pump...any of the wires feeding the pump getting hot? what gauge are they?

 

Nothing gets hot other than the pump and only when it is supplying fuel to running engine. If pump runs without car engine running, it will pump and recirculation fuel without a problem.

Wires, relay, etc are all normal temp.

Power wires to and from relay are 10 gauge.

Thanks

 

Check voltage at the pump with a voltmeter before starting the engine/12 volts or more.....keep the meter connected and watch it while someone starts the engine....watch the meter until the problem happens......maybe the voltage is slowly dropping causing the pump to quit.

Voltage drop is rare, but it happens.

 

Update.... installed Carter fuel pump. Everything else is the same.

Same issue. Fuel pump dies on test drive. Fuel pump generally pumps fine with engine not running. Pumps fine with engine idling. Dies on test drive after 1 -5 minutes. Still has 12 volts going to circuit breaker but not out of it. Bypassed the circuit breaker and limped home.

Then noticed something odd with the multimeter. While pushing on the circuit breaker with the probes to make good contact, I could recreate the failure. Brand new 30 amp circuit breaker has a short or something wrong with it. New 20 circuit breaker fixed the problem!

My apologies to Holley for assuming your pump was the issue. Going to stick with the Carter since it is A LOT quieter than the Holley though.

Thanks for the suggestions and help.