Electric fuel pump plumbing

[unfamilia 1,938]

Update progress

[ILIED 316]

How do you know you have vapor lock?

I surprises me that you can get that with an electric pump.
 

Now I dont know the boiling temp of of fuel at 7PSI, but I think it would be way up there.
Do you have a pressure gauge? Is it right at the carb?
Thats how you determine what pressure you have, not at the pump. Maybe even borrow a GoPro and put it at the gauge so when you road-test it, you can see exactly what's going on

[unfamilia 1,938]

Just realised if I change my adm webber to an xf one with fuel return from carb then possibly wont need pressure valve as any excess will flow back to tank...

[XFChris 126]

Vid to show how much flow fuel return line gets at idle.

 

 

Just realised if I change my adm webber to an xf one with fuel return from carb then possibly wont need pressure valve as any excess will flow back to tank...

 

Where is the fuel return line off the carb? I have a XF, but haven't noticed a return line off it. Maybe my carb is off an earlier model for all I know.

 

How do you know you have vapor lock?

I surprises me that you can get that with an electric pump.
 

Now I dont know the boiling temp of of fuel at 7PSI, but I think it would be way up there.
Do you have a pressure gauge? Is it right at the carb?
Thats how you determine what pressure you have, not at the pump. Maybe even borrow a GoPro and put it at the gauge so when you road-test it, you can see exactly what's going on

 

The car's stumbling got worse over the course of the drive, before eventually dying at a set of lights and not being able to restart. After a wait in a nearby carpark it was able to start again.

 

It's not the electric pump itself that is causing the issue. I now think it's a combination of fuel getting too hot, and not enough pressure.

 

I have now deleted the fuel return line, and the car drives decent again. 

 

In no way am I saying that my current setup (no return line to fuel tank) is ideal. I need to investigate why I was having issues after setting up the fuel system as it should be. Perhaps the check valve is faulty? Maybe I need one that cracks at a higher psi. Maybe my fuel pump isn't cut out for the job (From memory the ebay listing said it was about 6 or 7 psi). Or maybe someone in the past has tinkered with the motor, making it need more fuel than others do.

 

I'll road test it again when ambient temps rise again, as my latest test was around 7:30pm. Lower ambient temp may have had some effect on making the car run nicer.

[ando76 4,354]

Do you have a regulator fitted to the system?

 

Do you have a fuel pressure gauge set up of the reg?

 

Where did you T the check valve into the system? at the pump?

 

Photo of the pump and check valve set- up please.

 

I doubt you will need a check valve with a higher relief.  You should not be feeding the carb more than 7psi anyway so the relief will not be the problem.

 

I'm sure with a bit more info we can get on top of this. 

[slydog 7,873]

7 PSI is more than I fed my last solid cammed xflow with a 650 4 barrel.

[ando76 4,354]

yeah I keep BITZA to 6psi and the race car is at 6.5psi.  I mentioned 7 psi because the check valve is set at 7.5psi and will not be relieving until then - so it won't be taking away any volume. 

[Crazy2287 1,886]

I think someone needs to address the difference of operation between the electrical motor driven and the solid state type (Facet) pumps.

If you are running a solid state pump you do not need a return, They are by design self regulating and will also easily lift fuel up to the engine bay.

 

Going off basic principals here so some things would be wrong.

Solid state pumps use a coil to drive a pump diaphragm similar to how the old mechanical pumps worked.

Electrical motor pumps are your more typical rotary vein or impeller pump. They are usually not good as a lift pump (need to be close to the source of fluid or need to be primed) and will load up when their flow is blocked will slow the motor and increase current draw or if it's an ideal pump (no fluid escapes past the impella/veins) could get hydraulic lock and stall the motor. The reason tehy are used in performance applications is they can deliver a higher, linear and more constant flow rate then a diaphragm pump and at higher pressures.

 

Discuss:

[unfamilia 1,938]

So facet pump no return needed really.

[XFChris 126]

Do you have a regulator fitted to the system?

 

No regulator fitted.

 

Do you have a fuel pressure gauge set up of the reg?

 

N/A

 

Where did you T the check valve into the system? at the pump?

 

Check valve is T'd in between the fuel cut solenoid and the carburetor. It is approx a metre ahead of the pump.

 

Photo of the pump and check valve set- up please.

 

I doubt you will need a check valve with a higher relief.  You should not be feeding the carb more than 7psi anyway so the relief will not be the problem.

 

I'm sure with a bit more info we can get on top of this. 

 

This is the fuel pump I bought: http://www.ebay.com.au/itm/Electric-Fuel-Pump-12-volt-Solid-State-4-6psi-130-LPH-Petrol-Universal-New-/130721428894?pt=AU_Car_Parts_Accessories&hash=item1e6f9ab59e

 

Just realised it is a solid state. Must be different from a facet in some way. Forgot to take a pic of mine, but I've put mine where stock mechanical pump would sit. In engine bay down low. (Below cyl head level)

 

I haven't run a regulator yet as I assumed the regulator is just there to set an upper limit of fuel pressure, or is there more to regulator than that? I.E. does it stabilise fuel pressure somehow.

 

Pics of T piece as follows.The Tpiece is currently disconnected at the two opposing ends. But you may be able to picture what it would look like Teed into the hose with the blue sheath on it.

[ando76 4,354]

Yes crazy your dead right. Thats why I posted a pic of Jason's set up on a Holley blue (copy ) as they are a vain style pump and require a relief to stop loading the pump up on no demand.

[Crazy2287 1,886]

As far as im concerned "facet" is incorrect terminology and should not be used. But as far as i know they apply that word to solid state pumps.

 

Sorta like tablets..... There is a name for tablets... It's called a Slate PC and has been around for a LONG time so fuck you Apple. A computer "Tablet" is a human interface device for digitizing pen movements.

[ando76 4,354]

ok so I just viewed the image of the pump that you got off ebay - that is an old clacker style pump and would be lucky to produce over 6psi and 32gph as opposed to a holley blue which is capable of up to 14psi and 130GPH - which is a big difference.

 

personally I think the check valve is not required in this application - well in theory anyway - but it would seem that there is still fuel passing over it at idle which - if plumbed in correctly would indicate that the pump is pushing more that 6psi.  now I'm well confused. 

 

my brain hurts this morning - need to wait till the fog clears so I can work this one out.

[slydog 7,873]

Reckon yours is sore...

[ILIED 316]

I dont know if I've overlooked it, but can you tell us if you DO or DO NOT have a pressure gauge at the engine, please?

[XFChris 126]

I do not have a fuel pressure gauge at the motor.

 

Maybe at idle, the fuel demand at bowl is much less than 6psi, so pressure builds up in the fuel line?

 

Or I had the check valve pointing the wrong way.around? I had the arrow on it pointing in the direction of fuel flow back to tank.

[unfamilia 1,938]

On which line the return line??

[XFChris 126]

Yeah I had check valve on return line only. 

[ando76 4,354]

The check valve needs to be on the pressure side of the pump i.e. the outgoing side of the pump.  That way it will relieve when pressure in the system builds and it loads up the pump but to be honest I doubt that pump would be capable of pushing more than 7.5psi. 

a fuel pressure gauge somewhere near the carb would be handy to see what is going on, but to be honest that little pump should not cause pump load up issues like a Holley pump. 

[ILIED 316]

Maybe stop guessing.

http://www.ebay.com/itm/Marshall-Gauge-0-15-psi-Fuel-Pressure-Oil-Pressure-1-5-Midnight-Black-Liquid-/231080522535?pt=Motors_Car_Truck_Parts_Accessories&hash=item35cd78f327&vxp=mtr

 

If you dont even know if the pump is performing as a baseline, how can you determine what it might be doin  any other time?

[ronny 204]

Road testing has not gone too well.

 

I am getting vapor lock issues and  stumbling under load. (which I assume is due to insufficent fuel pressure at the carb)

 

-I've then insulated the fuel line from the T piece to the carb, but it hasn't made a noticeable difference to stumbing.

 

 

That will be a carb issue, nothing to do with the pump

You are starting with fuel in the bowls

After that once you are using fuel fast then the pump comes into the equation

[XFChris 126]

That will be a carb issue, nothing to do with the pump

You are starting with fuel in the bowls

After that once you are using fuel fast then the pump comes into the equation

 

Oddly enough the vapor lock hasn't reoccured since deleting the t piece and return line. Could be that the check valve is faulty.

 

Here are some MS paint diagrams of my fuel set up. As it's probably hard for the rest of you to visualise my setup in full.(Blue lines indicate rubber hose. Grey are the OEM hard lines)

 

Initial and Current setup

Setup with T piece

[ando76 4,354]

The second set up is how it should be set up. Have u got the check valve the right way around? On the end facing pressure u should be able to see a round metal disc. With Gentle pressure with a screwdriver you should be able to move the disc. Perhaps have the supplier test the valve for correct operation and pressure. Maybe it's faulty and letting too much fuel pass over the relief, effectively starving the bowl. That would be my guess.

[ronny 204]

I wouldnt put another filter for the return line

Also a 6psi max pump wouldnt need a reg/check valve

[ILIED 316]

Seriously, a fucken gauge.
What would be bad about puting one on?