This is important for all you FD owners with a large after market fuel pump. I found a potentially hazardous weak link in the factory Mazda fuel pump wiring.The blue plug in the first picture is soldered to the wires coming from your fuel pump. The blue plug sits inside your gas tank and is plugged into the white plastic connector on the underside of your fuel pump assembly. I'm assuming the extra amp's drawn by the large fuel pump caused the blue plug to melt internally. When the blue plug was inside the white female connector you couldn't tell anything was wrong. It was only when I removed the blue plug from the connector, did I see that it was all burnt up. The only indication that I had a problem was a slight miss at wide open throttle. My solution to the problem was to cut away some of the white female connector and soldered the fuel pump wires directly to it.
Anyone swapping an FD should ABSOLUTELY redo the wiring going to the fuel pump. It needs a relay and larger gauge wiring. Someone on the club documented massive voltage drop with the stock wiring in the car. Voltage drop means the wiring has big resistance, is getting hot, and eventually fries like that. This also means you could lose fuel pressure and could run lean (lol I think I just heard another rotary go pop).
This would make a good sticky with the wiring instructions on how to fix it.
I'm mildly retarded and even I knew the fuel pump needed its own lead and relay. Like Daniel said its a well known problem and is well documented
Does the wiring from that connector usually get modified? This is the first I've heard of that connector getting fried. I know that the stock FD fuel pump wiring has a lot of connections and can have a lot of resistance, but I don't see how that would affect that connector. The voltage drops through the stock wiring would cause the fuel pump to see less voltage, so that means the stock fuel pump would draw less current. It seems like the melted connector would be from too much current for that connection. It's been years since I've studied electrical though, so correct me if I'm wrong.
I finished my conversion in 2004 way before Dan wrote DIY FD harness for dummies.
http://www.ls1fc.com/pdfs/Harness%20hookup%20FD.pdfDan's instructions uses the same factory Mazda conections i used for the fuel pump.
Maybe we should let the moderator know of this, so others dont have the same problem I did.
I took that apart on mine and re did the factory connector with a larger gauge wire. gm has had some of the same issues with there fuel tank colnnectors it was taking out fuel pumps in trucks everyone thinks it was due to to running a tank till empty. it was due to terminal tension in the connectors causing teminal fretting or arcking and melting. this is why new gm pumps come with new connectors equipped with larger teerminals and more contact area.
I took that apart on mine and re did the factory connector with a larger gauge wire. gm has had some of the same issues with there fuel tank colnnectors it was taking out fuel pumps in trucks everyone thinks it was due to to running a tank till empty. it was due to terminal tension in the connectors causing teminal fretting or arcking and melting. this is why new gm pumps come with new connectors equipped with larger teerminals and more contact area.
Sorry to drag this back from the dead but do you have any additional information on this? Were you able to source the connectors and crimp your own thicker wires?
This is the best solution I've seen discussed on this board for people wanting to upgrade their in-tank wiring:
http://www.racetronix.biz/itemdesc.asp?ic=BCWS-001&Tp=It's fuel compatible, hermetically sealed, and each wire pair handles 14Amps. If you fuel pump requires more that 14Amps, just run both pairs in parallel for wiring capable of handling 28Amps. If you don't need more, use the other pair to run your fuel level sensor.
Lane