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MG MGB Technical - Replacement SU Fuel Pump

Does anyone know if the electronic SU fuel pump available from Victoria British comes with the banjo fittings? If not, which ones will I need to order?
CRH Hoebel

CRH,

We have given you suggestions, but you are not letting us know what happens. It seems now you want to purchase a electronic SU fuel pump without finding out what is really wrong.

The fuel lines on these cars are old. Before getting a new fuel pump I would replace the fuel lines. They come as a set and are cut to fit.

If you have two fuel pumps that overheat there has to be a reason and not necessarily the fuel pump.

I have the Carter pump you have and it has never heated up. So please let us know what you have done before spending more money on another pump that just may very well over heat.

The SU pump does not come with the banjo fittings. you need to purchase them seperatly. There are two types. One has a fitting type end and the other is smooth to just put the hose on with clamps. For you I would get the later type banjo and you need 2 of them.

Again, Please let us know what you have done so far to correct the problem than and only than would I proceed to the next step.

Ray

PS: It also help to keep you post and the thread together so that eveyone won't have to go back and forth to try and help you.
Ray 1977 MGB

Ray,
I took apart the old pump and found that, while not an SU, it is a point driven unit. The points looked fairly worn. Moreover, inside the pump was an acordian-like ruber hose that actuated with the shaft of the pump. It had a tiny hole, causing fuel to leak into the rest of the unit (where the points and such are). Prior to taking it apart, I did test it - it ran but wasn't pumping fuel. I think that as the hole got bigger, the fuel filled the rest of the unit causing failure. After it sat for a while, and some of the fuel drained, it would begin actuating again.

As for the new carter pump, why it failed is a mystery I'm still going to try to figure out. I had it grounded to the ground in the wire harness, and not directly to the car with a bolt by the pump. I'm not sure if this made a difference.

I havent given up on it yet. Just researching my options (re: the SU) Thanks for all your help so far!
CRH Hoebel

CRH - Ray is correct, you need to find out why the carter pump is stopping and heating up before you install an all electronic SU fuel pump. If there is an external cause for the pump to be stalling, like a vacuum being drawn on the fuel tank (bad tank vent) or an obstruction in the inlet line to the pump, then it will cause the same problem with the all electronic SU fuel pump but with more expensive consequences. When the all electronic SU fuel pump stalls in a current on condition, one of two things will happen (possibly both). 1) the circuit card in the pump will be overheated and burned, turning the pump into junk. 2) the internal swamping resistor inteh pump coil will burn out, in which case teh all electronic pump will cease to operate. Both of these situations were explained to me by the all electronic SU fuel pump expert at Burlen Fuel Systems where the pumps are manufactured.

Grounding the pump via the ground wire in the harness vice directly to chassis ground doesn't make any difference as long as the ground wire is properly connected to ground at the far end. In your case, since the pump worked at all, I would have to say that the ground wire is good. In any case, loosing the ground to the pump would not cause the pump to heat up (it will cause it to stop), but id would do that by intrupting the current path, which will cause the pump to cool off rather than heat up.

Ray is also correct in saying that none of the SU fuel pumps come with the banjo fittings. They also do not come with the banjo bolts or the proper gaskets, all of which have to be purchased seperately. Further, the newer SU fuel pumps come with a recess in the inlet and outlet ports where the banjo fittings mate to. This recess takes a 117 size 'O' ring vice the fiber washer as shown in the V/B catalog. Good luck - Dave
David DuBois

I'm also beginging to think that "gunk" in the fuel tank is part of the problem. If the sending unit end in the tank gets blocked up, could it cause a vacuum that the pump can't overcome? Could gunk be damaging the diaphrams in these filters? Until I have the opportunity to drain the tank (or replace it if need be) can I fix a fuel filter between the tank and the pump (in addition to the one by the carb)?
CRH Hoebel

Ray, I checked and my carter pump is not the P60504. I have a feeling that it is a pump not meant for the application at hand.
CRH Hoebel

Just a thought: could it be that your Carter pump is meant for fuel injection where the pump runs continuously?
If so, then the closing of the needle valves and pressure build up might cause it to "overload".
Maybe a long shot, but try to find out what application your Carter pump is made for.
HTH,
Rufus
Rufus Pool

CRH - The gunk in your tank IS the problem. It is probably blocking the screen at the end of the pickup tube and is the obsrtuction that I talked about in my earlier postings. This is different that pulling a vacuum in the tank due to blocked vent, but the end result is the same. Before you put any other fuel pump on your car, I would strongly suggest that you get the tank and the fuel lines between it and the pump cleaned of all foreigh material, otherwise you will continue to have problems regardless of the type of pump you use. I would have the tank dipped stripped to get all the gunk out of it and also any rust that is forming. Follow this with a good sealant to keep the tank from rusting in the future. It is not very pretty to see what rust particles do to any aluminum parts in a fuel pump.

A good check of the fuel pump is to place a hose connected to the inlet side of the pump into a can of fuel and first, with the line to the carburetors disconnected at the carburetors and directed into another can, turn on the ignition and see if the pump will pump fuel. If it does, reconnect the fuel line to the carburetors and re-run the test. The pump should fill the float bowls and then may or may not stop pumping (if the output pressure of the pump is set by an internal bypass valve, it will keep running even though the float bowls are full and have shut off any further fuel from going into them). Regardless of whether the pump keeps running or stops, leave power applied to it for awhile and see if it overheats (if the pump keeps running because it has a bypass valve, it will probably get somewhat warmer, but shouldn't get really hot).

It is doubtful that the pump is designed for fuel injection as pumps that are designed for that have a really high (around 80 - 100 psi) pressure and would overcome the needle valve closing and pump fuel out the overflow. Good luck - Dave
David DuBois

CRH,
I've had alot of grief messing around with SU pumps. Yes all of you orrigionality types, I AM predudiced about the loathsome things. Aside from the petrol soaked hours spent messing with it the damn things given me some truely awful moments of mortal peril on the road.
You could try a japanese pump. I put a second hand Subaru (1982) pump on mine as a temparary fix one day and left it there because it worked perfectly. I simply bypassed the SU with a bit of fuel line and put the Jap' pump up in the engine compartment jammed into an out of the way corner. I put a fuel filter before the pump to protect both it and the carby jets from gunk. I've read that the Honda civic pump is the same item. Check archives for details. They have way way more pulling power than the SU hence the "filter first and UP in the engine compartment, easily accessible approach". They are way cheaper than the SU pump.They even sound exactly like the SU pump (except of course for those long periods of non productive silence I've come to expect from these evil devices!). My second hand pump worked flawlessly until I installed the V8 fuel injected motor which needed a different approach.
If you are couragously intending to pursue the SU and have no fear of a painful and early death by the side of the road (I did say I'm predudiced), then you can get various bango type conectors at a hydrolic fittings shop.
Peter

CRH,

I have the P60504 installed on my 77 mgb.

This is a Carter (Federal Mogul) P60504 Gerotor,low pressure, self-priming, positive displacement pump. It's a 12v, 2.5-4.5psi, 30 GPH (Gallons Per Hour) pump. It's small, quiet and will keep the entire fuel line to the carb pressurized to alleviate any potential "vapor Lock" problems. It draws 1 amp and runs on 7 volts while it also gives over 5000 maintenance free hours of life. This is a great pump that is much cheaper than the SU's and you can't hear it.

As I stated, I used this pump with a Weber set up that usaually requires at least 3-3.5psi. This pump will do it. If you think it is to much psi by a regulator for $19.99. Again, I use this same pump now with my supercharger. I also now use a regulator because I do not need that much psi compared to a weber.

CRH, you now state you have gunk in your tank. Maybe this has blocked the fuel filter and the Carter pump is working so hard to pump gas that it is overheating. This pump wants to pressurize the system first.

Now if you have gunk in the gas tank, please disconnect the battery. Drain all the gas. Undo the screws on the bottom, take out the tank and flush it good. You need to start from there first. If you don't have a clean tank of gas you can't try and trouble shoot other areas.

This is a great fuel pump for $60.00 or less, and will last a long long time without problems.

Keep us informed,

Ray

Ray 1977 MGB

CRH,

Sorry, I misread your post. What Carter pump do you have? If it is the next one up 6-8psi than it will still work, just get a regulator. I could find out the number tomorrow, but still I would not worry. Your main concern now is to clean the tank.

Ray
Ray 1977 MGB

I've been using a Facet pump in my B and my Datsun (w/SUs) w/great success for many years. They're cheap and compact and are as noisy as a SU pump. JC Whitneys sells them for about $40.
Mike MaGee

I'm not sure if gunk is the problem, but it is a 25 year old tank. I did notice that after working on the problem fuel was not free flowing out of the tank outlet. The following day when I started again there was some free flow with the line disconected. Does the pickip inside the tank have a float that pulls it toward the top of the tank with the fuel level? According to the gauge, I'm at half a tank. If full, will it collect fuel higher?
CRH Hoebel

The whole story is in the thread "More fuel pressure woes." Please go to that onw. Sorry about the numerous threads. Thanks, Chris
CRH Hoebel

This thread was discussed on 22/08/2005

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