I'm trying to figure out if my fuel pump is broken or if it's the electrical that's broken. I have a 1964, Mk II, 3.8L. I had it in the shop to get driveable bc it was sitting for 20 years in the garage. They said they rebuilt ground connections on charging regulator, cleaned connected a on charging regulator tested it and said it was good. They rebuilt electrical connection on the fuel pumps and rebuilt the brake master cylinder.
I picked up the car and drove it about 3 miles and the car started smoking under the hood and spewing a ton of coolant. it ends up that there was an old hose that burst a hole. I was kind of upset because the mechanic said it was an old garden hose but why didn't he notice this before? He replaced the hose and everything seemed to be working fine. I ended up driving about 110 miles when the car started smoking a ton from
the exhaust. I pulled over and noticed the oil was extremely low so I added about 2.5 quarts. the car wouldn't start again so I was going to try getting it jumped but noticed the battery was hooked up negative ground. so I switched it. When I tried starting the car it started up nicely. I turned it off right away thinking it was fine. but when I tried starting it about 30 min later it wouldn't start again. it wasn't even turning over. I got it jumped and it turned over but the fuel pump had stopped working. I had it towed home. I recharged my battery bc it was super low but I'm trying to figure out what's wrong with the fuel pump. I noticed in the front near the voltage regulator that there's a wire not hooked up to anything so not sure if that is important... sorry if I gave too much irrelevant info. I just wanted to give all the info I know so far. there are also two fuel pumps on the car. let me
me know if you have any ideas. thank you!

 

this is a view from the front. the red wire on the left is the one I noticed just sitting there





this is a view from the top





another view from the top

 

Referring to the first photo, there's no connection to the top fuse (LHS) i.e. opposite the brown wire. Perhaps the red wire goes there?

 

Also, that label at the bottom LH corner of your last photo would seem to indicate the previous owner had the electrics converted to negative ground, so you should have let sleeping dogs lie. Maybe that's why the petrol pump is not working, it may have been upgraded to a polarity sensitive electronic type.

Without trying to sound somewhat superior, changing the battery to positive ground, without checking things, may have been a little rash.

Perhaps also, but upsetting the polarity, the battery has abnormally discharged itself.

Only one petrol pump was fitted by the factory.

 

I wouldn't simply connect that red wire back either until it can be determined why it was disconnected.
It looks like it's been that way for while _ you need to get yourself a volt/ohm meter and do some tracing (with the battery disconnected of course).
A simple 20.00 dollar multi meter will work for this.
If you're not comfortable trouble shooting electrical problems and reading wiring diagrams, then I would suggest that you have some one help you or get someone to do it for you.
I'll check the wiring diagram a little later today and see if I can find something obvious, but it's one of those things where the car has to be in front of me to trouble shoot.

EDIT:
Does your clock/cigar lighter/interior door lights/four way hazards (if fitted) work ?
If no one has jury rigged the wiring in your car, then the red wire (should be brown and I'm guessing that someone changed it) is live and is fed from the live side of the solenoid that turns the starter over. The live side if the solenoid is directly fed from the "live" side of the battery.
A simple check with a volt meter will show if the wire is "live" and it should be, even if the key is off.

If the above items are working (clock/cigar lighter etc.) then someone has changed things around, and none of the items should be working with nothing connected to that fuse terminal.
The 2 purple wires (one is faded to a light mauve colour) feeds the above mentioned items.

The other fuse powers your fuel pump/ignition/brake fluid indicator and they should be all white (according to the wiring diagram) someone has changed them to yellow and light/dark blue. Check that fuse for a cold connection by replacing it and make sure that the contacts are clean.
The green wires on the other side of that fuse are correct.

I'm betting that the brown wire has been disconnected from the solenoid and along with it, the Ammeter, which would make the loose red wire "dead" and the reason why the ammeter isn't working. But if they did that, then there would be nothing getting to the other fuse _ maybe the ammeter has been jumped _ the circuits that go through the ammeter would continue to work, but nothing would show up on the meter itself. Hard to say with out testing and physically looking at things.
You can easily follow the diagram to see what circuits are affected, assuming of course nothing has been changed in the actual car.
I've high-lighted the fuse that has nothing connected to it with a red rectangle. The brown wire (which it should be) is probably the red wire that has been disconnected _maybe it was changed because it was badly frayed _ assuming that the red wire is the brown wire.
This is where a multi-metre and a simple continuity test comes in handy.

EDIT:
Took another close look at your photos and upon careful inspection, there is one brown wire connected to the other fuse. The brown braided casing is pretty much all gone from the wire, making it appear black, but it is there.
So that brings us back to the mystery of the red wire and where it goes, what it's there for and if it's live.

 

that Red wire might be, (repeat: MIGHT BE), for one of the sidelights or turn signal indicators.

the car has the two tiny indicators on top of the fenders, and then you have the two Driving/Parking lamps below the headlamps. Do all lights work in the front of the car??

my advice is to follow the advice from JeffR1 and do not connect the Red wire to anything without first doing electrical checks. Something got screwed up when you reversed the battery cables, continuing to trial-and-error could result in a fried wiring harness. Put a piece of electrical tape on the exposed wire of that Red wire so it doesn't come in contact with anything.

if you are planning on keeping the car, get the Factory Service Manual.

does the car have a Generator or Alternator? If you do not know, or do not know the difference, I suggest you stop and find an automotive electrician.

NOTE: the fuel pump might have a Diode (some pumps do), and when you reversed the battery cables it might have fried the Diode.

Where are you located? Please note that adding your location helps other Members of the forum help you, perhaps you have another MK-2 owner nearby but they wouldn't know it since you don't say where you are. This is a pretty safe Forum, you need not be afraid of sharing your location.

 

A Mark 2 should only have one electric fuel pump situated inside the trunk behind the trim panel on the LH side. Pumps were SU, and when operating had a characteristic tick-tick whilst they were pumping. They did not pump continuously, only long enough for the (very low) fuel pressure to be achieved. Of course on cruise the pump would be working almost continuously.
A continuous 12v supply goes to the pump and it has internal contacts and pressure sensor to turn it on and off. When the ignition is turned on the characteristic "tick-tick" of the pump is usually heard and it then stops. Once the engine is started and using fuel the pump will come on again, but noise of road and car means it's not normally heard then.

However, with two pumps, and no picture, its difficult to decide what has been fitted to your car. Where are these two pumps located ?

 

KLDouglas -

The attached photos are for reference only. Please do NOT rewire your car to these photos! The pics here are for review that MIGHT assist in your wiring situation. Defer to Fraser, Jose, JeffR1, Red Triangle, and the rest for their knowledge base....

Since I have a 1964 Daimler, I went out and took pictures this morning. I'm told both the Mark II and Daimlers are similar this year, but I'm noticing items in your photos that are not inside my Daimler engine compartment. So there are differences.

That noted, the fuse box ( is that the correct term?) has similar construction and colored wires. See photos. This MIGHT assist in getting the color orders correct to what was originally there in your Mark II.

As to the mysterious red wire, I think I have that same wire also. But the one inside my Daimler -- as are numerous wires -- is covered by threaded burlap-like covering. So a full color determination is difficult, but it does seem to have a red coating and is in the same area you describe. See photos.

This red wire in my vehicle doesn't seem to go anywhere or connect to anything. BUT DON'T TAKE MY WORD FOR IT! I'm till learning.... but it seems to terminate above the fuse box into an oval rubber end.

This is all FYI.

BTW, why is there that burlap threaded covering on various wires?
Why on some wires and then not on others?

As to the other points in your original post, may I comment? My knowledge is enough to put o the head of a pin and still leave enough room for the fairies marching band, but I will ask some questions that may add to the conversation...

 

It may not be fuel pump problem otherwise it could give some indication.