RD Stephenson

I have a 01 Maxima that is not engaging the fuel pump relay when connected. The relay works fine when I hook it up to the battery but for whatever reason will not engage when plugged in. I thought the fuel pump was bad at first but when I jumped the relay the fuel pump works fine so it has to be in that relay somewhere. Has anyone ever ran across this problem before?

Whostheboog

Sounds like corrosion on the relay terminals or connector maybe. If not a new relay will probably fix it. My ecm relay for my 5 speed started acting up selectively and sent me through a nightmare. But every once in a while would click on and be fine...

DennisMik

iTrader: (2)

Please don't post the same problem in multiple threads. Here is my answer I typed in the other thread.

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This is one of the most mis-diagnosed circuits in the car.

There are 4 pins on the bottom of the relay. They are numbered 1, 2, 3 and 5. Look on the bottom of the relay for tiny, tiny numbers. If you see a diagram on the top of the relay, DO NOT go by that.

To start with, you should always measure battery voltage (12 volts) on 2 of the 4 relay connections, specifically pins # 1 and 5. Pin 1 is for the electromagnetic coil in the relay that closes the contacts. Pin 5 is the power that will go to the fuel pump.

Power to pin 1 comes from fuse # 1. Power to pin 5 comes from fuse # 29.

The ECU puts a ground on pin 2 of the relay to energize the electromagnet coil and close the contacts. When the relay contacts close the 12 volts from fuse 29 comes out of the relay on pin 3.

As I stated previously, the relay will energize for about a second when you turn the ignition key on and then de-energize if you do not crank the engine. What keeps the relay energized is the ECU receiving pulses from the crankshaft flywheel sensor CKPS[POS].

Your responses are a bit vague, so I am not sure of exactly what you have discovered. Please use more detail.

Whostheboog

If you're telling me to clarify my bad I try to be descriptive but I guess not so much. Basically my relay box was smashed when car was wrecked by previous owner. As a result they just hang there by the battery. Not thinking I didn't stand them back up right and condensation shorted and or ruined my ecm relay. It also caused a bit of corrosion build up on the relays connector so when I replaced the relay it intermittently worked. Cleaned connector and new relays terminals. Problems solved. Another problem I've been having is ever since I lost my key and the other key chips I have won't seem to work with the cars Nats I ended up getting the 2k1 Gle key key chip to work. But I still use it for the Gle so I have to hold them together when I insert and start the car. Sometimes if I drop the Gle key or forget to put it to the ignition my fuel pump will not kick on until I lock the doors, step out, close them, and proceded to unlock them with the key (I don't have a remote for this car only the Gle). After which when I pair the two keys, turn the ignition, and presto fuel pump.

RD Stephenson

When I plug the fuel pump relay in I can push it manually and it works fine, however, it will not engage without me doing it. I have been told that it could be the cam relay or the two crank relays. I just didn't want to go out and buy new relays if there was something obvious I may be missing. Car runs fine if I jump the fuel pump relay though, so I figured it would have to be somewhere in the wiring or on a connecting relay by the engine. I appreciated the suggestions to, thanks, my first Nissan I have ever owned and up until this point it has been a stellar vehicle.

Whostheboog

Gotcha kinda sounds like a broke wire possibly. I have dealt with quite a few at this point

DennisMik

iTrader: (2)

If you can push on the relay and it works, add a jumper wire and it works, it is not the relay itself. The pushing part makes me think that maybe the wire is backing out of the socket. Maybe you can look into the socket and see if the metal contacts are all the same height. If you can't tell by looking, you will have to take the entire plastic socket assembly out and look from the back side.

DennisMik

iTrader: (2)

I was not responding to you. I was responding to the op.

RD Stephenson

This car is driving me crazy. After putting a code reader on it I changed the crank flywheel relay sensor. After that it coded with a cam shaft relay sensor. Not it doesn't show a code but will still not start. I finally zip tied the fuel relay together so the car can run and be moved in and out of the shop but I don't know if rigging it up this way will cause the fuel pump or something else to burn up after awhile. Any ideas?

maxiiiboy

You keep asking questions, but you don't follow up on good advice given to you. Go back, and follow up on post #7 - it's the best advice you are going to get!

RD Stephenson

Maxiiboy, I did do that, and the crap didn't work. However, thanks for replying and letting me know how stupid I am. Starting to think you are dating my ex.

DennisMik

iTrader: (2)

I am missing something here. In post # 5 you say that pushing on the relay or adding a jumper makes it work. In post # 9 you say that you zip tied the relay together and it works. Those statements sound like the same thing to me, meaning you have a bad connection.

The camshaft sensor will certainly prevent the engine from starting, but I don't think it has any bearing on the fuel pump circuit.

Speaking of the fuel pump relay, have you tried swapping it with another relay? You only mentioned jumpering 12 volts to it. You could use the fog lamp relay (under the hood by the power steering reservoir).

havihav

Dude i wanna thank you .. I know its an old post but because you i was able to fix my car .. Thank you so much man !!!!!! I followed your guide for the fuel pump relay circuits and was able to find a cut wire that was causing a no start i repaired the wire and it was up and running .. Thanks again i created an account just so i can thank you ..