Fuel Pump Won't Work

[hybrid22l]

My car is almost done, but I can not get the fuel pump to work. When I run a hot wire to the fuel pump positive side, the pump will work and the car fires up. I need to figure out why there is no power running to the pump. There is power runnoing to the fuel pump assembly because there my fuel floaty is working. Any ideas guys?

[autotechmotoring]

I would first check the factory wiring using a test light or meter to see if your getting proper voltage to the pump. Check fuses and relays also.

If this is a project car that may have been sitting for a while, then your battery/charging system may not be up to par to start the fuel pump. If all that is fine, then I would check the wiring.

Hope this helps.

[hybrid22l]

Thganks for the tips. I did check the fuses, and they are good. The only thing I can think of is that the fuel pump relay on my s13 is bad.

[SochBAT]

Check the fuse relay in the engine bay. My guess its that. Everyone always forgets fuses, and start to alienate the _____ before checking the fuses.

[t0ttzg0tskillz]

I'm having this same problem. I have checked the fuse but I cannot find the pump relay. I have the cheap Chilton manual (IT SUCKS ASS!). Might someone be able to take a picture? Everything was working before I disconnected the tank.

[Father Time]

be sure the wires in the plugs near the pump didnt get lose. mine did last time i replaced the pump and it gave me fits till i found it.

[t0ttzg0tskillz]

Well, I know the pump works. I connected directly to the battery. What else could it be? I checked the Fuel Pump Fuse (#10) and it was fine. One question I have is what is EGI ? On the relay switches that someone said to be the fuel pump relay, it says EGI. There are 4 relays. Looking from the front of the car starting from the back. It's the 2nd one(green). What else should I look for?

[mjjstang]

EGI pump is the fuel pump, wehn you take out the relay, the pump shuts off, SOOOO... check that to make sure its working right,

[t0ttzg0tskillz]

Well, the pump doesn't start in the first place HAHA! So I wouldn't be able to tell if it was the relay or not. What else could I look for?

[g6civcx]

EGI is an acronym that stands for Electronic Gasoline Injection. This was used in the S12. The S13 actually has what's called the Electronic Concentrated Control System (ECCS). Nissan just didn't bother to relabel the relay box cover. So the relay labeled EGI Pump is your fuel pump relay.

You need to go to zeroyon.com and download a FSM for your year. They have S13 DE and S14 models covered. The wiring on the earlier S13 is very similar to the DE so you should be covered as well (I've only found very minor differences, and that's only if you're looking for differences).

I would say get a multimeter, or at least a test light to test for power flow. I built a test light out of a spare sidemarker light I had. Just take the bulb and socket, and strip the 2 wires to expose. When you connect one wire to power and the other to ground, the bulb lights up to let you know you have current flow.

Take your test light and go to the fuel pump wiring harness. It's located on the US right passenger side of the trunk. Pull the harness and use your test light to test for current flow. I can't tell you which wires because I don't even know which car you have. You will be able to find all of this information in the EC section of the FSM.

See if the pump is getting ignition power by hooking one wire to fuel pump wire and the other to fuel pump ground. The light should come on when the ingition is turned to ON.

If not, try moving the ground wire to the chassis. If the light comes on, you know you have a bad ground wire in the body harness.

If still nothing, then go check the EGI Pump relay. Again, refer to the FSM for wire colors. Check for proper power flow. If you have power at the relay but not at the fuel pump, there's a short in the body harness somewhere.

Also check the fuel pump wire coming from the ECU. That one may be damaged as well. That signal from the ECU goes to the relay, and the relay turns on current to flow to the fuel pump.

If any wire is shorted or damaged, or if the ECU isn't working correctly, your pump won't get power.

If you look in the FAQ section of Silvia, there's a writeup on fuel system upgrade. Go look for the connector for the blue fuel pump harness on the body harness, and that's the one you test. Also make sure you test the fuse because you can't always tell if it's good just by looking at it.

http://img.photobucket.com/albums/v317/bjorkluv/IMG_1921.jpg

[t0ttzg0tskillz]

g6civcx - I did pretty much all of that AND MORE! I have done enough to find that the relay isn't bad. It's just not being activated. I downloaded the FSM but I don't understand some things in there. I'll look some more. But I definatly know it's before the EGI Relay. It gets power. It's just not switching on. So, I don't know what to do as of RIGHT NOW.

[g6civcx]

If you say it's before the relay, go check the fuel pump signal from the ECU. Make sure the ECU is sending the correct signal.

Also trace the power flow that goes to the relay. Going backward, check the fuse. Then check the wire before the fuse because this is ignition power. If still no power trace it back to the ignition switch. If still no power then trace it back to battery power that goes to the ignition switch.

There has to be a broken link somewhere in that chain. I can't attach but look in the EC section for the fuel pump wiring diagram.

What specifically do you not understand in the FSM?

[NemeGuero]

LOL! That pic makes me laugh...

[t0ttzg0tskillz]

Hmm, could it be possible that when I removed the lines in the engine bay to replace the filter that I gave an error? I didn't release the pressure at first. I figured it was since I removed them down by the tank. Could this be a problem?

[t0ttzg0tskillz]

g6civcx - I found something in the FSM and i'm going to check it out tomorrow. How would I tell what signal the ECU is sending out? I don't have any programs. I get confused when I try to keep track of wires. They change colors/patterns more than once. I was thinking. Maybe I could try overriding the relay and pumping fuel into the lines thus getting the car to start. Maybe it's not working because a sensor for the injectors is saying something?

[g6civcx]

Okay, before you try anything complicated, try replacing the fuel pump fuse and the fusible links. Make sure these aren't blown.

Just because the fuel gauge works doens't mean your pump is getting power. They run on different circuits.

If that doesn't fix it, let's trace through the power flow.

1. The battery supplies power to the fusible link.
2. The fusible link connects to the ignition switch.
3. When the ignition switch is ON, power flows to the fuel pump fuse.
4. The fuse connects to the fuel pump relay.
5. When the ECU wants to turn on the fuel pump, it will draw current from the relay.
6. When the ECU draws current, the relay sends power to the fuel pump via the Super Multiple Junction (SMJ) box.
7. Power goes through the fuel pump and onto the ground wire.

If there is any disruption in this chain, the fuel pump will not work correctly.

I don't recommend hooking the fuel pump directly to the battery without a fuse in front of it, but since you already did that, how did you hook up the fuel pump directly to battery power? Specifically, which wire did you hook up to the battery?

http://g6civcx.angryhosting.com/S13/Tech/FuelPump.jpg

[t0ttzg0tskillz]

I am definately going to print this out! That's awsome! Well, I just used gator wires and connect to + and - on the motor. I guess I should have tried through the harness too. I have to take about a week off from this because I'm going to NC for some family things. But I will hit you up when I get back and let you know if this worked! Thanks alot for all your help man!

[g6civcx]

Whatever you do, don't hook the fuel pump or the ECU wire directly to battery power. That may damage the fuel pump or blow the ECU.

[rsxrcr87]

Ok so this same thing is happening to me. A year and a half ago the fuel pump worked and so did the CD player, windows and im sure a couple of other things but the main thing i need right now is the fuel pump I swapped a 94 Ka into a 95 5speed and the motor turns over but the fuel pump is not coming on at all. The battery is fully charged the fuel pump fuse in the kick panel is good. Not sure about the relay... but why would half of the car not have power now? I checked and double checked the connections on everything cleaned all connectors and battery terminals... im getting very frustrated. please what should i do next besides send it to a tech

[g6civcx]

Check your ECU harness. Sometimes when it's not seated correctly it'll do whacky things.

Then I would start checking all the fuses and fusible links in the relay box under the hood as well as under the dash.

If you still can't find it, then you have to start hunting for wires.

[cotbu]

I think you may have blown a resistor for pin 104.
1st check continuity on the wire. No continuity( track down problem, Check E9 & E10 conections also this wire is thin and will break if it sees any thing close to 12v) hint!!!

Message me if you need more in-depth info.
Like jumping the relay.

[OdessaS13]

sorry i didnt have time to read all the posts but when i was checking my pump i rember reading in the fsm that the fuel pump is assciated with the crank position sensor, that might be your rpoblem. also check pages EF&EC 33for trouble diagnostics, fsm does really good job on troubleshooting fuel system, but im sure someone already suggested that

[cotbu]

sorry i didnt have time to read all the posts but when i was checking my pump i rember reading in the fsm that the fuel pump is assciated with the crank position sensor, that might be your rpoblem. also check pages EF&EC 33for trouble diagnostics, fsm does really good job on troubleshooting fuel system, but im sure someone already suggested that
Elaborate please, because when you turn the key on, the fuel pump will prime regardless. The ecu checks for that 1º from the crankshaft position sensor after you have power not before. Which is not the problem here!