Fuel pump

I have run my Rover with two fuel pumps since the early 1990s. I have retained the mechanical pump whilst installing a solid state Facet beneath the tank. I can switch on the Facet with ignition on but the engine off. I like having this option, although I can appreciate that it may not suit everyone. For the vast majority of the time I just use the mechanical pump, but if I need to, I can switch on the Facet for some extra help. It is certainly invaluable when the vapour lock rear's it unwanted head, then with a flick of the switch, the problem is gone in seconds.

Ron
 
SydneyRoverP6B said:
I have run my Rover with two fuel pumps since the early 1990s. I have retained the mechanical pump whilst installing a solid state Facet beneath the tank. I can switch on the Facet with ignition on but the engine off. I like having this option, although I can appreciate that it may not suit everyone. For the vast majority of the time I just use the mechanical pump, but if I need to, I can switch on the Facet for some extra help. It is certainly invaluable when the vapour lock rear's it unwanted head, then with a flick of the switch, the problem is gone in seconds.

Ron
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Hi Ron
that sounds like good idea I would like to be able stop fuel flowing in case of problems
it’s already poured petrol out twice ! so avoiding that happening again is paramount
thanks regards paul
 
[ Pump runs with ignition on but engine not running]
Yes that's normal. There's not usually any need to have the ignition on and engine not running for an extended period. If you want something else to fret about the coil is powered as well, if the points are closed it can overheat it. You could put a switch in the pump supply wire and use it as a security device.

Colin
 
colnerov said:
[ Pump runs with ignition on but engine not running]
Yes that's normal. There's not usually any need to have the ignition on and engine not running for an extended period. If you want something else to fret about the coil is powered as well, if the points are closed it can overheat it. You could put a switch in the pump supply wire and use it as a security device.

Colin
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Hi Colin
I needed the ignition on to check the oil pressure switch whilst shorting it out to check where the fault was the pump ran and got past the carb valve resulting in fuel everywhere regards paul
 
The pump is running because of its higher pressure output opening the float valve. If the pressure was lower so the valve could hold it it back when the float chamber is full the pump would stop. You might still want to consider an inline pressure regulator. That’s a lot easier to fit than running a return line (not all SU carb systems had a return line fitted)
 
Facet pumps run continuously. They are noisy if not rubber mounted. They need a pressure regulator, and need setting up with a pressure gauge in the line to read pressure before the carbs when the engine is running.
 
SydneyRoverP6B said:
I have run my Rover with two fuel pumps since the early 1990s. I have retained the mechanical pump whilst installing a solid state Facet beneath the tank. I can switch on the Facet with ignition on but the engine off. I like having this option, although I can appreciate that it may not suit everyone. For the vast majority of the time I just use the mechanical pump, but if I need to, I can switch on the Facet for some extra help. It is certainly invaluable when the vapour lock rear's it unwanted head, then with a flick of the switch, the problem is gone in seconds.

Ron
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Ron gave me his idea years ago and it works great, fitted a few of the pump upgrades to mates after they experienced vapour lock on hot days.
Thanks Ron.
 
My car has a Facet pump mounted on rubber bobbins at the back near the tank, but there is no pressure regulator in the fuel system. The return line is as it left the factory. I haven't suffered the dreaded vapour lock for many years. Now that I've typed that, I expect I'll be stranded at the roadside as soon as the temperatures here in London get scorchio again!
 
cobraboy said:
Facet pumps run continuously. They are noisy if not rubber-mounted. They need a pressure regulator and need setting up with a pressure gauge in the line to read pressure before the carbs when the engine is running.
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That's interesting. Mine is rubber mounted, and whilst it does tick, you don't hear it whilst driving. I investigated at the time, and no pressure regulator nor gauge was required. I assume that there would be other variations that may need what you state. I have never had a problem, no overflow, nor anything else untoward.

Ron
 
My memory of P4 tanks is that the pickup entered on the top of the tank, with 2 different lengths of pipe - long for reserve, slightly shorter for main. A solenoid controlled which pipe was used.
 
SydneyRoverP6B said:
That's interesting. Mine is rubber mounted, and whilst it does tick, you don't hear it whilst driving. I investigated at the time, and no pressure regulator nor gauge was required. I assume that there would be other variations that may need what you state. I have never had a problem, no overflow, nor anything else untoward.

Ron
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Facets come in various outputs in GPH and max pressure. Being greedy I always buy a big un and regulate it down, as you know SU carbs don't like much pressure, but you want adequate flow, as running lean at WOT gets expensive.
 
fitted mine (facet type) under rear of car as a 'push' rather than suck. inline fuel filter removed and another see through (easy strip and clean) fit din engine bay on inner wing away from heat sources. ideally a return line out to be fitted so cooler fresh fuel can be pumped when ignition is on. having suffered many fuel vapour issues. flooding carbs and engine running on 3-4 cylinders after a restart when parked up for any length of time. until carbs get fresh (bubble free) fuel and engine suddenly runs like a sewing machine. only thing I found is the 'restrictor' in return fuel line has far too small a hole to allow full fuel flow return ( designed for mechanical pump ) in hindsight ought to have drilled it out to much larger diameter bore. V8's do not like hot fuel. ethanol creates bubbles and it's this that can give many restarting issues .having an auto I can't afford to keep cranking away to get rid of bubbly fuel! as to best position for fuel pump I can now attest ( having RAC attend etc) that engine bay and a suck type pump is best. carb overflowing will be excess fuel pressure and or carb fuel valves not seating. ( had mine replaced twice) no fun when you pull up and sudden heavy smell of fuel and puddles creating under a hot running engine!! ( sorted now) good luck with you issues.
 
Hi, Drilling out the small hole in the fuel return union could cause more problems than it solves. It's that size to resist fuel flowing through so that the fuel goes into the carbs where it's needed, then once the float valve is closed it can allow the fuel to pass. It could be said to act like a simple pressure regulator. The passage through the float valve is restricted to some extent by the valve and seat. So if opened up too much it could starve the carbs because it will want to take the line of least resistance.

Colin
 
colnerov said:
Hi, Drilling out the small hole in the fuel return union could cause more problems than it solves. It's that size to resist fuel flowing through so that the fuel goes into the carbs where it's needed, then once the float valve is closed it can allow the fuel to pass. It could be said to act like a simple pressure regulator. The passage through the float valve is restricted to some extent by the valve and seat. So if opened up too much it could starve the carbs because it will want to take the line of least resistance.

Colin
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Hi Colin
i did think that so eventually I’ll hopefully be able to track down something from A car someone is breaking
I have to say it’s not very easy finding the parts but it all comes o he who waits !,
 
Fuel flowing from SU float chambers might not be due to too much fuel pressure. My 3500S started doing this suddenly, after water pump replacement. Nothing to do with water pump; I thought needle vale not seating, so replaced both and reset float/valve shut-off point. Still leaked.
Totally mystified, I phoned Burlem Fuel Sys.., and was advise to replace floats. Despite floats being in apparently perfect condition, no leaks.
new floats were instant cure. Burlem said that old floats, made of brown plastic, should be replaced with new floats, white plastid but otherwise looking identical.
Fuel system had been OK before having to replace water pump, and not touched when replacing pump. but.... mechanic told em that things often go wrong after major work on another par of the car.
 
colnerov said:
Hi, Drilling out the small hole in the fuel return union could cause more problems than it solves. It's that size to resist fuel flowing through so that the fuel goes into the carbs where it's needed, then once the float valve is closed it can allow the fuel to pass. It could be said to act like a simple pressure regulator. The passage through the float valve is restricted to some extent by the valve and seat. So if opened up too much it could starve the carbs because it will want to take the line of least resistance.

Colin
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understand that but I am of opinion pump can provide high flow rate and easily fill carbs eve at high speed /loads. having tried flow rat into an empty can I was amazed when its running and engine is 'off' it does not spill fuel past carbs overflow pipes onto floor!
 
Recently acquired 1972 3500s it stopped a few times in traffic through lack of fuel, bubbles or no fuel in the filter ,which after extensive reading , I believe to be vapour lock ,as after 30 minutes when the car cooled down it started no problem.
I decided to have an electric pump(from Wadhams) and regulator fitted next to the coil.Still have the return pipe to the tank fitted and have the regulator set at 3 , the car has been idling for 30 minutes all fine so took it for a drive for 20 minutes and returned to find fuel pouring out of the pipe that runs in front of the engine and empties straight onto the road this is on the offside carb .
Any help and suggestions would be appreciated.
 
What are the specification for the pump that you purchased, Paul?

Aside from the pump parameters, a float that has taken on fuel will sink delivering what you describe, fuel pouring onto the ground while the engine is running.

Follow a process of elimination. Either remove the o/s carburettor and check the float, or disconnect the new pump and refit the old. If no fuel pours from the overflow, then you have found your problem.

Ron
 
My P6B has the factory electric pump mounted under the tank on bobbins with the res tap mounted on the tank outlet. However The car is a 1976 chassis with a 1971 Engine so uses the earlier carbs. I found out quite quickly that the factory Facet pump (nor any other electric pump) cannot keep up with the flow with the standard return line and I needed to reduce the size of the return line fitting to provide sufficient back pressure at higher speeds. I've tested every available electric pump and none were able to provide sufficient fuel at high speed without the return line reduction.

Consequently I suggest your issue is inside the float bowls. Either the float issue stated above or the needles not seating/leaking. You will need to retune the engine afterwards as the float level affects the mixture control in an SU carb.
 
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