OK, so back in the fall my car decided to stop running after I did a dash swap(I was hoping that this was a coincidence). I narrowed the problem down to the fuel pump. After checking the connection to ensure that it was recieving 12V, I decided that the fuel pump had finally just gone bad (it was the original). So I ordered a new pump from Mazdatrix, and installed it today. Unfortunately the new one is not pumping gas either. I checked the connection again and it is still getting 12V. When I bench tested the original pump, it pumped like crazy (yeah, I probably should have done this before I bought the new pump, but I figured if it was getting 12V, then it wasn't a power supply issue). So now I have spend $120 on a new pump, and my car is still not running. What could be the problem? It is definately a power issue. Could it be a bad ground? Where does the wire ground to? Please don't tell me I have to take that stupid dash off again! Thanks in advance, and sorry about the long post.
John

 

If you're getting juice, I have a feeling that you hooked them up backwards (or you checked the wrong wire for voltage). Im not sure what color code the new pump came with but they usually come with red and black. black, the negative wire, can be connected directly to the frame/chassis. I cant remember the stock color code so you will need to check the wiring diagram.

If you're in a hurry, run a new wire but use a relay which can be triggered by any of the ignition wire. OR, if ur lazy, run a wire from the battery to the pump but install a fuse in between (Instant fuse holder = cut the wire and crimp a female connector on each end). To turn off, remove the fuse.

 

Actually it was the stock so the connector is the same. It is a T connector so there is really no way to hook it up backwards. Is it possible for the polarity to be reversed somehow to the connector? Doesn't seem possible to me, but I am no expert on the car's wiring. Thanks for the reply. Keep those ideas coming.

 

Use test light or VOM on the stock connector to identify the positive wire and to ensure the presence of juice.

Use 2 short pieces of jumper wires so you can reverse the polarity; say A1wire to B2wire, A2wire to B1 wire. If it works, then the manufacturer fucked up in the replacement pump's polarity. Just to play it safe, install a fuse in either wire.

 

Well it is doing the same thing with the old pump, so it has to be in the car wiring somewhere. I will check what you are saying. I could of made a mistake of course. Thanks again for the replies.

 

if you have juice, then its just an open circuit. Cut the wire with no voltage and ground it directly to the frame/body of car. Hopefully its only a grounding issue.

 

That's a good idea. I will try just jumping the ground to the body tomorrow and see if that helps. I hope that is the problem. Thanks for all of your help.
John

 

Fuel line filter!!!!

 

Is that different than the fuel filter. I changed the fuel filter at the same time. Besides, I am almost positive that it is electrical. Thanks.

 

I'll bet it's the rear ignitor. When this fails, it cuts off the fuel pump (ask me how I know). Before figuring out my fuel pump wasn't working because of the failed rear ignitor, I learned to wire the pump, through the left storage compartment, to the lead for the rear hatch light. This got the car running again; now I keep a jumper wire in the storage compartment in case the rear ignitor goes out again, killing the pump.

 

I will keep that in mind, but I just figured out the problem. I got rearended back in the fall, and took the license plate lights off so that the body shop could fix the dent and repaint. Unfortunately the car never made it to the body shop because the car wouldn't start because of the fuel pump. Well the fuel pump wouldn't go because the ground for the rear harness which includes the fuel pump is wired onto the license plate light screw. So the ground was not connected properly therefore the pump could not get adequate power. I connected the ground and sure enough, the fuel pump pumped fine. Thanks to everybody for your help. At least now I can get it to the body shop! Thanks again.
John