Relay Testing and Fuel pump help

[nefiwashere]

Pic of how I wire up the relay. Grounded both arms move. No ground only 1 moves.
I poke at the solder points and the wires but nothing changes. Still get no continuity on grounded.


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[Captain Obvious]

If you are getting the correct reactions on pins 91, 95, and 97, then the relay is working properly.

I suspect the "failure" you are seeing on the test between 95 and 96 is a test procedure error. You're trying to measure resistance on a device while it's under power, and your meter is not interpreting the results as you would expect.*

Out of curiosity... What resistance do you read between 95 and 96 if you swap the two meter leads? Put the meter on the 2K range, not the 2M range.

 

 

* For those who care... The Ohmmeter works by applying a small known voltage across the device being tested and then measuring the amount of current that flows. If you try to measure the resistance of something that already has a voltage applied to it, the meter doesn't interpret the results correctly. And in this case, if pin 95 is connected to +12 and 96 is connected to ground, you're putting an Ohmmeter directly across a 12V power source. Meter will display incorrect results.

[Zed Head]

I did ponder the measurement of resistance on a circuit that had voltage.  My reasoning didn't give me an answer.  A test light to represent the pump circuit might be a better test.  I thought that somebody had found a flaw in Nissan's overall test procedure for the pump control.   Maybe that was it.

The test results don't fit the original problem very well.  As SteveJ noted in post #11.  I just tried to move things along.  Might have extended the barking instead.  Sorry.

[nefiwashere]

1 hour ago, Captain Obvious said:

If you are getting the correct reactions on pins 91, 95, and 97, then the relay is working properly.

I suspect the "failure" you are seeing on the test between 95 and 96 is a test procedure error. You're trying to measure resistance on a device while it's under power, and your meter is not interpreting the results as you would expect.*

Out of curiosity... What resistance do you read between 95 and 96 if you swap the two meter leads? Put the meter on the 2K range, not the 2M range.

 

 

* For those who care... The Ohmmeter works by applying a small known voltage across the device being tested and then measuring the amount of current that flows. If you try to measure the resistance of something that already has a voltage applied to it, the meter doesn't interpret the results correctly. And in this case, if pin 95 is connected to +12 and 96 is connected to ground, you're putting an Ohmmeter directly across a 12V power source. Meter will display incorrect results.

I get   .059 on the meter.

so my relay is working as it should.   If thats the case what else can be causing my fuel pump to turn off?   seem that after it runs for a bit it stops pumping, I dont hear it whining.  

[SteveJ]

7 hours ago, nefiwashere said:

I get   .059 on the meter.

so my relay is working as it should.   If thats the case what else can be causing my fuel pump to turn off?   seem that after it runs for a bit it stops pumping, I dont hear it whining.  

Loss of signal on the oil pressure switch. Your oil pressure sender has two posts. One goes to the oil pressure gauge. That one will have variable resistance. The other post is linked to a switch. When you have enough oil pressure, the switch closes and provides a path to ground. It's a way of killing the fuel pump if the engine stops running. A bad sender or low oil pressure in the engine could cause the pump to cut out.

[nefiwashere]

Loss of signal on the oil pressure switch. Your oil pressure sender has two posts. One goes to the oil pressure gauge. That one will have variable resistance. The other post is linked to a switch. When you have enough oil pressure, the switch closes and provides a path to ground. It's a way of killing the fuel pump if the engine stops running. A bad sender or low oil pressure in the engine could cause the pump to cut out.

I see. To test it do I just disconnect both wires?


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[nefiwashere]

Also, thanks everyone for all the help so far.


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[Zed Head]

13 hours ago, nefiwashere said:

 If thats the case what else can be causing my fuel pump to turn off?   seem that after it runs for a bit it stops pumping, I dont hear it whining.  

The pumps do wear out or get damaged.  I had one that I picked up from a wrecking yard that worked great for about 5 minutes then slowly lost pressure and started making noise.

FastWoman has posted about one that she had in her car that did similar.  This might also explain the drop in voltage that you mentioned early on, as the motor gets loaded up and pulls more current.

Might be worth your time to remove the fuel pump and bench test it.  Or crawl under the car, set your meter up on the pump terminals measuring voltage, and have somebody actuate the pump for you.  You'll hear it and see what voltage is doing.  If it looks great with a low voltage drop for a minute or two but slowly drops voltage and runs slower, that's a clue.

[nefiwashere]

The pumps do wear out or get damaged.  I had one that I picked up from a wrecking yard that worked great for about 5 minutes then slowly lost pressure and started making noise.
FastWoman has posted about one that she had in her car that did similar.  This might also explain the drop in voltage that you mentioned early on, as the motor gets loaded up and pulls more current.
Might be worth your time to remove the fuel pump and bench test it.  Or crawl under the car, set your meter up on the pump terminals measuring voltage, and have somebody actuate the pump for you.  You'll hear it and see what voltage is doing.  If it looks great with a low voltage drop for a minute or two but slowly drops voltage and runs slower, that's a clue.

I can give that a try, but it is a new OEM fuel pump.

After some reading on this site I noticed that my fuel damper is bypassed. Didn’t think anything of it cause I thought it was a small filter. Having it bypassed cause any of my related issues?


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[Zed Head]

I would just set up your volt meter, remove your oil pump sender connection and turn the key to On.  The pump will start running.  Watch, listen, wait.  It should sit at 36-37 psi for hours.  That's what it does when you're driving, it just sits back their and spins.  Watch the gauge, listen to the pump, and wait for something to happen.  If nothing happens and fuel pressure holds steady, you're problem is probably not related to fuel pressure.

Break the problem in to small pieces.

[nefiwashere]

I would just set up your volt meter, remove your oil pump sender connection and turn the key to On.  The pump will start running.  Watch, listen, wait.  It should sit at 36-37 psi for hours.  That's what it does when you're driving, it just sits back their and spins.  Watch the gauge, listen to the pump, and wait for something to happen.  If nothing happens and fuel pressure holds steady, you're problem is probably not related to fuel pressure. Break the problem in to small pieces.

 

I did as you suggested and turning they key to the on position the fuel pump is working but it looks like its not getting gas.   I have a clear fuel filter on the outlet of the pump and its barley pushing any gas into it.  it get some pulses of gas but its not very much and sometimes it goes a good while with no gas pulsing in. is that normal or should there be a constant flow of gas ?   i have put at least 10gal of gas so i know there is gas in the tank.  sometimes during when it does pull gas from the tank i here some burping in the tank.   when i turn the car off i also here some burping. 

 

Meter stayed around 11.45 volts

 

some extra info

there is a dent in my tank on the passenger side.   i know the outlets are also on that side.   Inside the tank how do those outlets look? are they flush to the inside of the tank or are the tubes inside as well?     had the car for years and never had an issue with the tank cause of the dent.  car also had the tank removed and cleaned out cause of bad gas.

 

Pic of dent attached

 

[Patcon]

What year car? It's not in your signature line...