Claff Reader
8/10/13 12:27 a.m.

I'm trying to get my stupid MGB running again after I dragged it out of the barn it spent the last 12 years or so in. I farmed out the actual 'get it running' to dear old dad, who volunteered for the project and probably instantly regretted it. But he got it running a couple months ago and told me to come get my heap out of his yard. I did so, driving it onto my trailer under its own power. Stopped on the way home to put half a tank of gas in it. Got home and the stupid thing wouldn't start.

I traced the likely problem to the old fuel pump getting tired. It clicked merrily away but the innards weren't capable of moving gas adequately. Dad said don't get a SU pump, they're expensive. Get a Facet cube pump. Easy install: two hoses, two wires, idiot-proof.

Which means I've become a pretty good idiot. Hooked everything up and nothing happens. The pump will work if I touch the wires to battery terminals, so that's good, but it doesn't work hooked to the wires under the car. The old pump will, which is frustrating and baffling.

One suggestion is that the ground isn't robust enough, but I hooked the + wiring to the pump and touched the pump's - to the battery terminal and got nothing. So I have to trace the + wire to find a fault that's apparently not bad enough to affect the old pump but is bad enough to affect the new one.

I need a test light, but can't find one at Lowes or Home Depot. Are these things that you make yourself out of scrap parts or what? Or should I just get one of those multimeters?

Automotive electricity is probably my second-least favorite areas to work on, after bodywork. This allegedly easy fix that isn't fixing anything is a big reason why.

ransom GRM+ Memberand UltraDork
8/10/13 1:15 a.m.

The multimeter seems like a better bet to me; if it's good enough to run the old pump, it may be good enough to make the bulb in a simple tester come on, and that won't tell you much...

There isn't a huge amount of wire on an MGB, I wouldn't think (not by half-modern standards). Seems like it shouldn't be world-ending to check that + wire at its ends and then along the way if cleaning up the contacts at the ends doesn't help...

Actually, here's a question for you: A quick google suggests that some MGBs are positive-ground: So hooking one wire to battery + and the other to ground would be applying no voltage at all, as it would be equivalent to hooking both sides to battery +. Do you know that yours is negative ground?

Curmudgeon MegaDork
8/10/13 6:24 a.m.

ransom's on the right track. MGB's were positive ground until 1967, those cube pumps won't work on a positive ground system. If your car has a generator instead of an alternator chances are it's positive ground. It's not difficult to swap a car from positive to negative ground with the exception of the tachometer, if that's what you decide to do just unplug the tach till you can have it modified for negative ground. (Actually you can do it yourself, there's a few tutorials on the Web.) There's plenty of good instructions out there on how to convert the car from positive to negative ground.

If your car is already negative ground then all the above is a moot point.

As far as a test light, any parts place should have them for less than $10. I'd do that instead of a multimeter for right now since all you are doing is verifying power is where it needs to be at the right time.

One other thing I have seen many times: those Lucas 'Lucar' connectors consist of 'bullets' soldered to the wires, then a metal sleeve those 'bullets' snap into and finally a vinyl sleeve that the metal sleeve goes into. When they get old the metal sleeves will get brittle and crack, meaning the vinyl is the only thing holding them tight to the 'bullets'. This means when you probe for power there will be enough to light the little dinky bulb which draws a minimal amount of power but when you plug in a higher demand item such as the fuel pump it just can't get enough power to do its thing. The connectors at the ignition switch are particularly bad about this since they carry the zap for everything else in the car. The white wires at the ignition switch are the ones for the ignition system and fuel pump.

Lucas wiring color codes.

Ian F
Ian F PowerDork
8/10/13 6:48 a.m.

Just a quick suggestion since it turned out to be the issue with my '64 Mini (dual SU carbs): Check to make sure the carb bowl floats aren't stuck shut. There may have been enough fuel in the bowls to start the car and get it on the trailer, but not afterwards. Granted, the fact the SU pump was clicking away before suggests this is a long shot. I almost spent $$$ buying a new fuel pump until this was suggested to me. Popped the bowl tops and sure enough - carbs were bone dry and the jets were stuck closed. Blew them clear with carb cleaner and it's been good.

Any automotive store should have test lights. I seem to remember a Pep Boys in Waldorf.

Positive ground is fun... a car that's been hodge-podged converted to negative ground is even more fun... the wiring in my Mini is a mess. If I keep the car, one future project will be rewiring the blasted thing.

Apis_Mellifera Reader
8/10/13 8:59 a.m.

Stick with an SU fuel pump. Mainly because the carbs will leak due to over pressure unless you manage to find a Facet with low enough pressure. The SU pump also is on-demand. The Facet runs continuously and it's loud. Even if it's deadheaded, the Facet will run. The SU would shut off. If there is air in the line, both will run. Disconnected from the fuel line, both should run, which will eliminate flow as a controlling variable. Ground the - on the Facet to the battery, then with the key on, briefly touch each car FP wire to the + wire on the Facet to see which works. Obviously a test light would be better for that type of troubleshooting, but it will work

I have the original SU pump in my '58 MGA. Works fine, provides the pressure and flow the carbs want. They work, they are easily rebuildable, and reliable provided they aren't neglected in a barn for 12 years. Moss or VB will have the parts to fix it.

8/10/13 9:10 a.m.

I would be curious to hear what all got done to get the car running after 12 years of slumber.

Unless someexpensive fuel system remediation was done, getting the car running would have been the equivalent of flushing a giant turd down the fuel line and into the carbs.

Not even sure why you are mucking about with electricity: The pump is clicking so chances are they thing is trying to push fuel.

Start on one end or the other: open float chambers and have a look to see whats in there? Clean flush as required.

Remove fuel line at carbs, observe with pump running while collecting fuel. How does fuel look

Keep going back and clean out everything. The SU pump is pretty simple and easy enough to open and clean. Even replacing parts is not a big deal if you are trying to save a buck.

The fuel tank is going to be the can of worms; hard to clean those suckers without pulling and cooking out the grunge; I just buy new.

When done, put in new filter and be prepard to change it often for the first while.

TRoglodyte Dork
8/10/13 9:15 a.m.

Hook the new fuel pump up to alligator leads and buy 2 gallons of premium gas in a brand new gas can. Bypass the old tank and fuel pump and hook up directly to the carburetor. I would bet that the fuel tank has rust flakes blocking the outlet. The new fuel pump should not pump over 4 psi. A multimeter will tell a lot more about voltage and amperesif you know how to use it, but a 12 volt combination volt/ ohm test light will tell you 95% of what you need to know.

Giant Purple Snorklewacker
Giant Purple Snorklewacker MegaDork
8/10/13 9:48 a.m.

Put the old fuel pump back on. Take a screwdriver handle and rap the float bowl a few times and fire her up.

Claff Reader
8/10/13 9:53 a.m.

Some answers:

Car is grounded negative. It's a '71 with a decal under the hood that says WARNING: THIS CAR GROUNDED NEGATIVE EARTH. It's been converted to a single standard 12V battery.

The biggest hurdle to getting it going at dad's was some flaky wiring in the distributor. This made no sense as the car was running when parked, nothing had changed except for hibernation.

The old pump was kaput. It's labeled "AC Spark Plugs" and the rubber inside was shot. It would pump gas out of the tank and onto the ground but if I hooked up all the lines it wouldn't get gas to the front of the car. I'm trying to find someone local who has a SU pump stashed away so I can try that, but I know very few Brit car owners down this way.

I'm not going to let this car defeat me. I've had it since 1987 and we've gone through a lot of adventures together. I realistically want just one more summer together for old time's sake and then figure out what to do with it after that: it's going to have a hard time getting miles sharing the driveway with four Miatas. But it's got to move under its own power before we get around to making any further decisions.

Flight Service
Flight Service MegaDork
8/10/13 9:59 a.m.
Curmudgeon wrote: Lucas wiring color codes.

you my new friend!

mattmacklind UltimaDork
8/10/13 10:00 a.m.

Even though this site is the best of its kind, don't forget MG Experience, you might find the person with the part you are looking for nearby.

Rupert Reader
8/10/13 10:06 a.m.
Claff wrote: I realistically want just one more summer together for old time's sake and then figure out what to do with it after that: But it's got to move under its own power before we get around to making any further decisions.

Well let's see, it is August and theis car has "hibernated" how long? I'd say by the summer of 2014 you should be able to get it running under its' own power.

However, a car that old, with that much "hibernation" is one that unless totally gone over by an expert will probably keep you very busy. And I don't mean busy driving!

I suggest once it is running under its' own power, you place a very conspicuous For Sale sign on your old car early next summer.

wlkelley3 SuperDork
8/10/13 10:09 p.m.

Your preference of test light or multimeter but HF has digital multimeters ranging from less than a test light to the cost of a couple test lights. Maybe not accurate enough for some detail work but more than accurate enough for this. As you can tell, I prefer multimeters.

On thing about European car wiring, no take that back all old car wiring is they will deteriorate over time. That wiring is 40 years old and insulation breaks down and core becomes brittle and may break internal causing current drop.

By the way, same goes for rubber lines. Metal lines may corrode internally. May be why fuel doesn't get to the front of the car. (also applies to brakes)

Hibernation is bad on a car.

Curmudgeon MegaDork
8/11/13 6:32 a.m.

Back to the OP: the pump with the car clicks when powered up but the Facet pump doesn't. That's either insufficient power (hence the need for a test light) or a bad replacement pump. It's very possible the floats are sticking as well, I generally rap on the top of the chamber with a plastic screwdriver handle as a temporary measure to get it to fire.

By the way, if that pump says 'AC Spark Plugs' it's not an SU pump. It's probably the old EP12:

That's been out of production for quite a while. It also does not play nice with alcohol fuels, for that matter the Facet 'cube' pumps didn't like that stuff either. The newer Facet and AC pumps that look like a fuel filter work okay with it, though.

I have one on my J-H and it's only audible for the first 5-10 seconds of operation. OBTW, if you get on with those plastic fittings do NOT use them! Get some brass fittings, do it once. Somewhere in all my crap I still have an original cast metal SU pump from my car, the replacements are plastic and not worth a tiny pinch of coon E36 M3.

Ian F
Ian F PowerDork
8/11/13 8:27 a.m.

In reply to Curmudgeon:

Do you need to run a regulator with that pump? Looking at the O'Reilly site, it say 5-8 psi which I understand is quite a bit more than SU's can handle. Price does look good, though... $69 online. The SU pump in my Mini still seems to be working fine, but it wouldn't hurt to have something in reserve.

Curmudgeon MegaDork
8/11/13 9:01 a.m.

I'm running Dellortos and it works fine with them. For SU's yeah it might be a good idea to run a regulator if it leaks, although I have seen these pumps installed and not leaking. Those cheapie CR Pro Fuel regulators will work fine.

MichaelYount Reader
8/11/13 9:53 a.m.

This - "Automotive electricity is probably my second-least favorite areas to work on...." + this "I'm trying to get my stupid MGB running again after ......12 years or so ..." =

The good news is that it's all pretty straightforward and there's lots of stuff available today to make it much easier. How's is coming?

Claff Reader
8/14/13 4:03 a.m.

Haven't had much time to play with the derelict this week. We're semi-serious autocrossers and this is the fun time of year where we have stuff going on pretty much every weekend including a little boondoggle to Nebraska in a couple weeks.

I might be inspired to fiddle with it some tomorrow. I really do want to get this thing running.

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