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MG MGB Technical - solid state fuel pump

I have just fitted a new solid state fuel pump to my MGB and it is much noisier than the original pump with points. Is this common or do you think I have a faulty new pump? Purchased from MG Owners club in the UK which supplies good stuff.
Cheers
Les
Les Howard

If it is a SU pump it should be no noisier then the old pump. If it is one of the block style pumps made by Facet and others, they are louder. Mount it on a rubber mount to reduce the noise.
John H

Les - Welcome to the world of the little square, run all the time, make a lot of noise, Facet fuel pumps. They are a good pump, but they do make quite a bit of noise and run constantly, making the noise that much worse (on the other hand, the all electronic SU fuel pump is actually a bit quieter than the points style pumps). You can get standard sound mounts to install the Facet pumps on, which will completely isolate the sound from the passenger compartment so you car barely hear it, even with the engine off. To see the style of sound mounts that are very effective, go to: http://www.pegasusautoracing.com/advcat.asp?CategoryID=AIRFUEL click on Fuel Pump Accessories and look at item 1130. Cheers - Dave
David DuBois

If it is from the MGOC it almost certainly is an SU *style* pump as that is all they show on their web site. However they sell two types of electronic, what they term an 'OE' (but isn't as the factory never fitted electronic pumps) which is the SU and an alternative at half the price which is the plastic-bodied Moprod type. The SU uses the original mechanicals but electronics instead of the points, the Moprod is very similar. As such both should make a very similar noise to the original SU points type, but it's possible your original pump (which has failed?) was going out of adjustment and that tended to make it quieter. After many thousands of miles with a Moprod (PO fitted) on my V8 it started playing up intermittently and causing fuel starvation, and there is nothing you can do with these electronic pumps once they start doing that. After the 3rd bout I got fed up and fitted a refurbished points type and have had no more problems since. I'd rather have a points type that gives fair warning, can usually be encouraged back to life to get you home, and clean and readjust the points every 30k or so than have another pointless pump.
Paul Hunt

My "solid state" SU pump sounds exactly the same as the OE one. You can hear it at idle, if you listen for it if you are busy doing something like moving forward in a traffic queue then the click stops registering.
Stan Best

Been thinking about a back up pump for my 66B as mine is at least 22 years old. SC parts show a Mitsuba, wondered if anyone has tried them?

John
John U

John - "Been thinking about a back up pump for my 66B ..."

See the article, Backup Fuel Pump in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ Cheers - Dave
David DuBois

Thanks Dave, your site (plus Paul H and Chris B and others) has long been in my favourites. Just replaced the wiring loom, when I can face crawling underneath again this job is on the list!

Just wondered if anyone had experience of the Mitsuba but just had a thought that it might high pressure?

John
John U

I found solid state pumps from JC Whitney a few years ago, small, round, fit perfectly where the old SU was and very reliable. You can barely hear them. I don't know if they still carry them but if not, you can go to a Napa dealer they may be able to hook you up.
They look like a metal fuel filter actually.
It's a generic unit sold hi or low pressure.
Sorry I just checked JCW doesn't have them anymore, but I bet someone carries them. The brand is not Facet. I know Jeff Zorn of Little British Car Co in the States (lbcarco@lbcarco.com) had some at one time. Maybe he can point you in the right direction.
Samuel Sullivan

I remember now they were sold under the Walbro name. I just visited their web site but looks like they dropped the pump. Too bad. You could get their number call them and find out who the supplier is.
Samuel Sullivan

John - "Just wondered if anyone had experience of the Mitsuba but just had a thought that it might high pressure?" Peter in Australia may have used those, he talks about some Japanese pumps. As long as the pump puts out between 2.7 and 4 psi, they will work fine on a MGB.

Samual - Walbro pumps can be found here: http://www.autoperformanceengineering.com/html/bel_pump.html
They are an impulse pump the same as SU pumps and since they use points, they are vulnerable to the points filming over if the pump sits idle for long periods of time. Cheers - Dave
David DuBois

Dave - The pump is not a bellows type pump. I think it works the same as the Facet only it is round and doesn't make as much noise. It runs continously.
Maybe they aren't made anymore, but I have had mine on my GT for almost 20 years and my roadster for 10.
No issues. Walbro would remember them and maybe suggest where the came from.
Samuel Sullivan

Samuel - There are a couple of round, after market pumps, one of them being a Carter, but there is another one that is larger in diameter than the Carter. See the article, Backup Fuel Pump in the SU Fuel Article Section of my web site at: http://homepages.donobi.net/sufuelpumps/ for part numbers, one of them may be the one you are looking for. Cheers - Dave
David DuBois

Yes, I used the pump from my old broken down '82 subaru with no problems at all. It went great. Made the same sounds as a SU, except I had it stuffed, more or less out of sight, into that small space at the top, back and LHS side of the engine compartment, with some foam wrapped around it. Fuel filter before the pump. The tight space and fuel hoses kept it in place without the need for brackets or any new holes to be drilled. Thats about the same location you will find it in a Subaru. A very quick fix one day, just to get me to work, that stayed in place until I fitted the EFI V8 quite a long time later. The fuel pump wire plugs into a small group of bullet connectors rear RHS, white on my car.
Others have said that a Honda civic pump from about the same time also goes well. My Subaru pump had the Mitsubishi symbol on it so I'm guessing that this pump was fitted to many carburetor Japanese cars at that time.
The only regret was that I took the trouble to bypass the SU pump with some fuel line, which apparently was quite unnecessary, as you can pull straight through this style of pump I am told. This, I am also told, should also go for the Subaru pump (except push through in this case) if anyone wanted to plumb in a back up.
Peter

Just to add my two cents.... As much as we all like to stay original or do an upgrade such as the solid state su which I have myself, fuel pumps are very basic. Any pump will do as long as it has the required pressure and flow needed. I feel functionaliy of such a part should trump originality if it is keeping the car on the road.
James

"As much as we all like to ... do an upgrade such as the solid state su ..."

Include me out of that!
Paul Hunt

If the 'solid state' fuel pumps are contstantly ticking/working how do they control fuel pressure/supply to the carbs? SU's presumably only tick when more fuel is required to feed the carbs?
Ron Stevenson, Scotland
R Stevenson

Ron - The pumps that run continuously, like the Facet pumps, use a bypass valve (or relief valve) that sets the output pressure. That is how they run continuously and still operate at the correct pressure. A pump being solid state has nothing to do with the continuous operating or the output pressure. Solid state is a reference to how the coil is turned on and off. In a points style SU pump, the points closing and opening supply power to the coil. The energized coil pulls the diaphragm up, drawing fuel into the pump when the points are closed. When the diaphragm reaches its upper limit, the points open and allow the volute spring to push the fuel out to the carburetor. In a solid state (or all electronic) pump, the coil is turned on and off by a transistor controlled by some type of electronic circuit. that circuit can be a magnetic trigger (in the case of the older Auto Pumps from New Zealand), an optical trigger (which I use in my modifications and Auto Pump is now using in their newer pumps) or a Hall effect circuit as used by Burlen Fuel Systems. Cheers - Dave
David DuBois

Or to put it another way SUs only tick when delivering fuel regardless of whether they are points-type or solid state. Some aftermarket types like Moprod are the same as SUs. Other aftermarket types tick or buzz all the time, again regardless of whether they are points, solid state or anything else.
Paul Hunt

Ron, Maybe you know this but the fuel is pumped to the carb float bowl, not directly to the carb/needle.
jjralston

Last week I had need to check on local availibility of fuel pumps for my '72B, and found several in the <$100 range. I especally like the ones with the removal bottom bowl with the fuel filter in it. This may be what I install when I move my pump back to the right side of the right battery box.

I was checking on availibility because my car was sputtering and dying out on me, after running just fine the day before, which turned out to be a very plugged fairly new fuel filter. I've since gone back to the perfectly clear inline filter, so I can observe future obstructions.

In the process of determining it was the filter, I decided to pressure test the Facet (brass block) fuel pump mounted by my heater motor.

I had a steady 5 psi pressure and vacummn. This was air pressure, no gas. I also decided to let the pump partially fill a can so I see if there was more debris on the way.

I see most mention the low pressure fuel pumps as being 2-4 psi. Is 5 too high? Or is the 5 simply within pressure gauge error?

Thanks for all the assistance.

R.W Anderson

RW - 5 psi is what I would call boarder line high, but it is difficult to get a good reading on an impulse type of pump (which the Facet and SU pumps are), since the pressure peaks each time the pump cycles. If you are not experiencing flooding or overflowing of the carbs, you are probably ok with the pump. Cheers - Dave
David DuBois

This thread was discussed between 09/07/2008 and 28/07/2008

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