my fuel pump is not getting any power?

Question

i first thought that the pump was bad but i was reading my manual and it said to check if the pump was getting power so i checked with a test light and it is not getting any power. i made sure that the fuse was good why else would i not be getting power to the pump? the manual said something about checking the relay but i dont know were it is does anyone knoe were it could be (its a 96 Nissan 200SX) so my question is were is the relay located and if its not the relay what else could it be?

i have the manual ill go look now thanks

were is the fuel pump relay? the manual says it has one but doesnt say were it is and its not were all the other ones are

Answer 1

Relays are usually under the hood in a main fuse box---the box lid should have a diagram of which fuses or relays control what systems. If relay is not bad, you'll have to get a wiring schematic to follow the circuit for where the power comes from or install a new power wire to the relay and bypass the old circuit....could be a shorted out switch, wire or fusible link. Some cars have the circuit going through the oil pressure switch to cut off the power to the fuel pump if you lose oil pressure in the engine.
Wirediagram.com or Eautorepair.net have schematics for a small fee.

Answer 2

Need some clarification: How did you check fuel pump voltage? Without the engine cranking (asusming everything else is working right) the fuel pump will ONLY prime for about 5 seconds, and no further power will go to the pump. I'm not familiar with that particular vehicle, but GM was pretty consistent that vintage on how the fuel pump operated, so confident I can get you close. You need to find the fuel pump relay. On the full size trucks that vintage it is an oval black plastic piece mounted to the firewall on the passenger side. Sometimes there will be multiple relays (AC's, fans, etc) but the fuel pump one MAY have a single red wire hanging off of it that is connected to nothing. Putting a wire from the battery directly to that wire should energize the fuel pump, so you can hear it run, or test for voltage at the tank plug at the rear of the vehicle. If you get voltage that way, then the pump or tank wiring internally is shot. If there is no hanging red wire, you can still test, just find which wire goes to the fuel pump from which relay, disconnect that plug, and put 12V to that terminal on the plug, and test again for voltage at the tank plug. You need to make absolutely sure you are getting a good ground while testing with your meter, I normally run a continuity test if I think my ground is iffy, and my voltmeter is telling me there is no/low voltage where I am expecting it. If you don't get voltage by putting 12 volts to the wire going to the tank, then you have a break in that wire. I wouldn't worry about the fuel gauge yet. It may be related, but the circuitry is completely separate for the two. The wires are run together though to/from the tank, so if a break, if may mean both were cut. If I were you, before running 12V to the fuel pump wiring, I'd check continuity between the tank pump power wire and ground, to make sure the wire isn't grounded out if it were cut/abraded. Short lesson, the fuel pump gets 12V from the relay (and probably the oil pressure switch bypass) and the fuel gauge signal wire runs from the sending unit to the gauge. The tank is grounded to the body by a wire off the tank to the body or frame. So if the fuel pump isn't running when it should, it isn't getting power, has no ground, or has failed. Easy as heck to test/narrow down. If the pump runs with the relay bypassed, the relay could be bad (although the oil pressure switch is normally used to bypass the relay if it's bad by design) or the power feeding the relay could be bad, which is more likely a fusible link, normally located around the starter, alternator, or junction block. I think you are smart enough to realize you don't splice into the wiring to test, that's why they have plugs you can disconnect all over the place. Cutting/splicing wires only leads to electrical failures that are impossible to figure out later on, when the wire under the tap is corroded, or the wire gets loose and the wires short to ground.

Answer 3

Main fuse/Relay box by the battery, you need power at two points (With the ignition on) on the 4 contact relay for it to work. if You have power there go back and pull the pump fuse before you replace the relay (Safety), Check the fuse a second time to be sure it's really good? Replace it. If the pump is good that should fix it.

Answer 4

The fuse is under the dash - or in the glovebox.

The relay is under the hood in a black box.

Also the ground wire will cause no power. It attaches from the top of the tank to the chassis of the car.

Answer 5

Here's the fuel pump relay found at AutoZone

Answer 6

check the wireing back from pump also if you can get a manuel it will show you where all of your relays are. Try your local nissan dealer ring them ask for the maintance department speak to mechanic they are useally very helpfull and its free to ask .

Answer 7

last time that happened to me, the wire from the engine to the pumphad been cut by something.