So I've got my fuel pump replaced and I'm about to crimp the walboro connector to the internal connector; I line every thing up and cut the wires. I then proceed to absentmindedly turn the now cut old connector over in my hand a few times. When I look at it again, I realize that the wires are both black and I have no idea what the polarity of the plug is.

I'm posting a pic of the connector in the hopes that someone can tell me which wire is positive.

Yes, it was dumb. I know.

 

I don't recognize that plug, but maybe it's an S5 change. Here's a picture of a walbro pump in my S4 assembly. The ground just connected to the metal body, and the power wire ran up to the harness. On the walbro side, red = positive & black = negative (of course). Maybe it'll help.

 

Yeah, I guess it's an S5 change. If I only had one wire, it'd be easier. As it is, the original fp had three wires coming off it: one hot, one ground to the connector and another ground that connects to the fp assembly.

Here's a couple more pics of the connectors.

 

You should still be able to trace the wires up to the plug on top, then compare the wire colors on the vehicle harness side to figure out which side is which at the pump.

 

shouldn`t you be able to use the continuity setting on meter and go from wire to ground and listen for tone, had to do that on my battery cables

 

I think I've got it sorted. I spent a good bit of time looking really closely at the cuts on each of the wires and seeing which ends fit better with each other. I decided that the right side wire in the pic was hot.

I had a friend come over last night for cigars and I was bitching about my stupidity and he took a look at them. Turns out under the florescent lights, you can just see a little bit of the inner insulation was blue on one wire (hot), but not on the other. This matched with my earlier puzzle piece method. I guess 20 years in the gas tank turned the outer part of the insulation black.

I've wired up the fuel pump and found which connector on the assembly cover is the hot tab. I'm going to put the battery in the car and check the mating connector to verify.

 

What fuel pump are you swapping to? Im running Holley pump and it runs great.

 

I got the walboro 255

 

and there is also polarity markers on the pump just below the connector...

if it doesn't have those then it's not a walbro which would also explain the craptastic 2 black wire connector.

 

Call it a hunch, but from what I remember (and a refresher, from the pic) if you're holding the clip as though you're going to connect it to your optic nerve, the hot is Left... Or right, from above and behind...

Or on the top, if you're standing on your head....

 

The connector I cut was the stock connector that clips into the gas tank side of the fuel tank cover. The connector that came with the walboro had the black and red wires and the pump is marked for polarity, so hopefully I have a genuine article. Says walboro on the side, at least.

 

Uhhhh, what?