Jack Freeman

Recently bought a 1965 327/350 Coupe and drove it a few miles with no problem but now when I shut it off and turn key on there is a noise that sounds like an electric fuel pump. After investigating I found on the frame under the A/C an object that said it was a Facet electronic fuel pump which is installed in line with the mechanical pump. My question is this additional fuel pump supposed to run all the time as long as the key is on and the motor not running? The first few times I drove the car the pump made no noise at all. After doing some research I found out these pumps were used to eliminate flooding and vapor lock and other problems associated with heat. Can anyone help me with this problem as I never heard of an electronic fuel pump...Thanks!!

PinkVetteLady

Congrats on your new purchase, It appears that along with your mechanical fuel pump you have an electric fuel pump. BTW pretty much all cars now have an electric fuel pump. I'm not sure why the original owner that you purchased this car from would have put both a mechanical and an electric fuel pump on the car. I would suggest removing one or the other. If you don't have a fuel pressure regulator I would recommend removing the electric pump. The mechanical pump works just fine in most applications.

Jack Freeman

I have had electric fuel pumps before back in 60's but this not an electric fuel pump. It is an electronic(solid state). The electric fuel pumps of the old day actually had an electric motor that turned a pump. This thing is about 1/2 the size of a pack of cigarettes and has no moving parts I don't think.....There has to be some reason for the addition of this other pump such as vapor lock I suspect....The actual question is does the pump supposed to "run" with the key on with motor not running?

Plasticman

Unless the owner wired it differently, yes it is suppose to run when the key is on (with the assumption that the engine would be started and running when the key is on for any period of time).

Sometimes, these pumps were wired through an "extra" oil pressure switch, so that they would be turned off if no oil pressure was present (as a safety). But most owners did not add that feature, since it would also require a method of bypassing that oil pressure switch in order to start the pump, and fire up the engine.

The problem with any electric fuel pump is accident safety. If an accident occurs (especially where the driver is incapacitated), and the engine is not running, but the electric fuel pump continues to pump fuel through a broken fuel line or damaged carb...........

Some manufacturers use inertia switches as well (a sudden shock, and the switch trips and opens the electrical feed to the pump).
http://www.therangerstation.com/tech...tiaSwitch.html

Why the previous owner added it is a mystery, but probably an attempt to cure a vapor lock. A properly functioning mechanical pump is all that is needed.

Here is their website (evidently still being sold):
http://facet-purolator.com/index.php...d=16&Itemid=31

Plasticman

Tony Mongillo

I wouldn't be surprised if the pump was wired to come on with a momentary switch to prime the carb if the car wasn't run for long periods of time. It would only run for a short period of time to fill the carb and the mechanical pump would be used for normal running.

There are a couple of different ways to hook up the switching for the electric pump. Some folks wire the pump to the solenoid so that it only runs when the engine is cranking and is off at all other times. Others install a separate momentary switch somewhere under the dash and just activate the switch to prime the carb.

If it isn't obvious how it is set up, just follow the wires from the pump and you can sort out wether it is set up for full time operation, or as a priming pump.

Tony

Plasticman

I assume the pump is in series with the mechanical pump. Therefore putting a non functioning electric pump (if only used for priming) on the suction side of a mechanical pump would act as a severe restriction to fuel flow (would hurt high load operation). Very poor application.

Plasticman

JohnZ

If there's no motor, it's not a pump. Sounds like one of those "miracle nuclear-magnetic fuel molecule straighteners". I'd remove it.

Jack Freeman

It DOES NOT have a motor but it is most defiantely a pump. This is all solid state. It will fully replace a mechanical fuel pump on a Corvette and while doing so it will pump from 6-34 GPH at a pressure of 1-11.5 PSI according to their web site. From talking with very knowledgeable mechanics it seems it must have been used to combat vapor lock and/or flooding but still don't know if it should run all the time that the switch is on or not being the original pump is still there.....

Plasticman

I thought I answered that question........................

I repeat: If it is in series with the mechanical pump, it MUST RUN ALL THE TIME THE ENGINE IS RUNNING, otherwise it will be a restriction to the fuel flow.

JohnZ

Interesting - made in England, and their website says they run at 5000 rpm; Aircraft Spruce sells them for aircraft applications. Had never heard of Facet pumps before.

chris ritchie

Jack, I've heard of this modification. I was thinking of doing it to my car. Here's what I know.

I believe many piston engined propeller aircraft use electronic and mechanical fuel pumps. Aircraft people love redundant systems. Electronic pumps are located near the tank because they are better at pushing fuel than pulling it. Mechanical pumps pull fuel better than pushing, so they are located at the other end. Both pumps allow flow through. Perhaps they do impede flow. But it isn’t enough to matter. The mechanical pump can pull fuel through a defective electrical pump, and the electrical pump can push fuel through a defective mechanical pump. Not sure if this is true of all pumps. But I do know it’s true of the Facet electrical pump and the AC Delco mechanical pump. (BTW, look at the mechanical fuel pump on a Lycoming engine. Look familiar?)

Plumbing an electric pump in the fuel system helps with a vapor lock problem.

More importantly, the electric fuel pump can be used before trying to start the car to fill the carburetor bowl. Many old car people (myself included) report that fuel evaporates from their carburetor in about 7 days. If you run the old car less often than weekly, you’ll need to crank it a lot to get it started. That’s because of the time it takes for the mechanical fuel pump to get gasoline to the carb. With an electrical fuel pump, you simply energize it, and it pumps gas through the mechanical fuel pump to the carb. This saves your starter.

Most (all?) modern cars have electrical fuel pumps. All of them have safety switches that’ll interrupt power to the pump in case of an accident. Usually the electrical pump is energized anytime the ignition key is in the “run” position. But if the car were in an accident, the engine would stall, but the circuit would still be energized. This is a dangerous condition because the pump would still be pumping gas even though the car was disabled as possibly have broken fuel connections. Not good. The interruption devices are a shock sensor or an oil pressure sensor. I would not want to drive around a car that did not have any of these interruption devices. But I suppose the electrical fuel pump could be wired so that it’d only run when separately turned on. Perhaps through a dedicated switch and circuit.

I don’t know why, but everytime I’ve heard of this modification, a Facet pump was recommended. Perhaps it’s because they’re cheap, small, and readily available through the usual hot-rod stores (Jegs, Summit, etc.). I didn’t know Facet made all those models. Which one is on your car?

One more thing. If your mecahnical fuel pump diaphragm gets a hole in it, the electrical fuel pump will pump raw gas into the crankcase. Of course, a hole in that diaphragm will leak gas into the engine without the electrical fuel pump. If you do or keep this mod., this should be something you keep an eye on.

VetteRed1965

Aircraft Spruce also sells a kit airplane pump for less money !Same just\not FAA certified

Jack Freeman

I guess this restriction issue is now resolved. This just in from Customer Service at Facet/Purolator

Our pumps allow fuel to go through them when the power is off. So you can
mount it in series with the mechanical fuel pump no problem, you should not
have any restriction.

Thank you

-------------------------------------------
Edison Moreira
Engineering Manager
Motor Components, LLC
2243 Corning Road
Elmira Heights, NY 14903
607-737-8383
607-737-8335



Chris, I have the pump they call the Cube Pump. Very small and looks very cheap but from what I'm hearing they are a quality product. I appreciate you posting this info. I knew no idiot would put two fuel pumps in series unless there was a reason and it was approved for whatever application he was trying to fix. I believe it was either to fill the carbureator bowl after a time of setting or vapor lock and flooding or all of the above. I'm going to leave it but will wire it different and probably put a switch on it. Again thanks for the post and information.

Plasticman

If you really believe that an additional pump will have no resistance to fuel flow, then I have a bridge for you...........

It has to have some type of check valves that will offer some restriction. I know, that is what the manufacturer said.

Plasticman

Jack Freeman

I can't keep from believing the company that made this product knows a lot more about it than you......Tell them that you have a bridge.......Read again what the company said about THEIR pump and if you don't agree argue with them.....