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Discussion Starter #1
Hello:) I have a 2005 Altima with the 2.5 auto. When I first bought the car I ran out of gas on the first day. I’ve noticed that the gas gauge works fine from full to half but after half it is in accurate and have ran out of gas multiple times. I know it will get about 425 miles to a tank but would like to gas gauge to work properly. I figured it was a bad fuel pump unit so I replaced it. That didn’t work. So I replaced the dash cluster (used) to see if that would fix it and nothing. So now I’ve pulled the pump back out of the car with it connected and I can make the gas gauge move properly from full to half full and to empty. It’s seems to be working then. Put back in tank and still inaccurate:( Nothing seems to be in the way in the gas tank. So I’m just confused on why it doesn’t Work properly. Just wondering if anybody else has had the same problem with theirs and maybe they were able to fix it. Thanks for all your help:)
 

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It's not enough that it works with pump out and turned on. The swing of the fuel level arm must match the tank depth closely. If say the arm touched bottom of tank and you are reading at half tank then you see the problem. The arm has to be bent to where it reads at zero with it at the proper distance for bumping bottom of tank. Your arm setting point is NOT full, it is always empty. Also, if there is any stiction in the arm working that will make it tend to hang at that point over and over. Ethanol in local fuel often does that, you have to work the arm and even take it off sometimes to make it frictionless if possible. Ethanol induced corrosion inside the tube and on the rod that serves as axle.
 

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Is the float arm properly mounted? Facing the trunk when installed?
My rule of thumb with sending units is the float arm should sit level with the base of the sending unit at the lowest point.
Occasionally I have run into baffles that have come loos in the tank and interfere with the float arm, but have never had a problem with a Nissan one
 

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'Rule of thumb with sending units is the float arm should sit level with the base of the sending unit at the lowest point.'

Great idea that may not necessarily work well. You have to have some idea of the construction of the module, some can have an entry slightly higher than pump bottom and then you are too low. I tend to set looking at absolute fuel height and set the level to slighter higher to make sure the gas gauge always goes slightly below zero to prevent running out of gas at exactly zero, which can be a problem. Because if you are at zero, sometimes you will run out before zero, they are never exact repeats. I throw out the last 1/4", you never ever run a tank 100% dry of fuel, they run out before that at the sloshing fuel finally becoming so small an amount the pickup in module loses prime before grabbing it. If not using a module and pump is out in the open you toss the next 1/4" too as the fuel quits going into the strainer as soon as the top of it is exposed, the air then acts like a break to stop pickup. Meaning top of strainer is the fuel level setting point. I often build a primer tube to direct older type pressure regulator return fuel to impact the top of strainer to stop that.

You have to look at what you have there and work it as needed.
 

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Discussion Starter #5
It's not enough that it works with pump out and turned on. The swing of the fuel level arm must match the tank depth closely. If say the arm touched bottom of tank and you are reading at half tank then you see the problem. The arm has to be bent to where it reads at zero with it at the proper distance for bumping bottom of tank. Your arm setting point is NOT full, it is always empty. Also, if there is any stiction in the arm working that will make it tend to hang at that point over and over. Ethanol in local fuel often does that, you have to work the arm and even take it off sometimes to make it frictionless if possible. Ethanol induced corrosion inside the tube and on the rod that serves as axle.
Ok thank you! I will take it out again and see if it’s level with bottom of pump. It seems to (after the half full mark. It seems to linger in one spot. Shit the car off and start again and fuel level is in a different leave?! Just Wierd! Thanks for the info:)
Is the float arm properly mounted? Facing the trunk when installed?
Rule of thumb with sending units is the float arm should sit level with the base of the sending unit at the lowest point.
Occasionally I have run into baffles that have come loos in the tank and interfere with the float arm, but have never had a problem with a Nissan one
ok thanks! I’m going to take it back out and see if it’s level:)
'Rule of thumb with sending units is the float arm should sit level with the base of the sending unit at the lowest point.'

Great idea that may not necessarily work well. You have to have some idea of the construction of the module, some can have an entry slightly higher than pump bottom and then you are too low. I tend to set looking at absolute fuel height and set the level to slighter higher to make sure the gas gauge always goes slightly below zero to prevent running out of gas at exactly zero, which can be a problem. Because if you are at zero, sometimes you will run out before zero, they are never exact repeats. I throw out the last 1/4", you never ever run a tank 100% dry of fuel, they run out before that at the sloshing fuel finally becoming so small an amount the pickup in module loses prime before grabbing it. If not using a module and pump is out in the open you toss the next 1/4" too as the fuel quits going into the strainer as soon as the top of it is exposed, the air then acts like a break to stop pickup. Meaning top of strainer is the fuel level setting point. I often build a primer tube to direct older type pressure regulator return fuel to impact the top of strainer to stop that.

You have to look at what you have there and work it as needed.
Thanks!!! I’m watching the fuel gauge over the next couple days:)
 

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Discussion Starter #6
So it’s still not working properly. I think it’s in the gauge cluster in dash? Is there a way to test this?
 

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If this from the OP was correct..............

'I can make the gas gauge move properly from full to half full and to empty.'

..........then most likely nothing wrong with the gauge.
 

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Discussion Starter #8
So your saying if the pump showed it worked properly when we had it out the gauge in cluster should be fine?! I just don’t know what else to check??
 

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And where everybody ends up. I'm telling you, if the arm or float is compromised on pump you have to be able to think it out to get it back. The resistor track on pump indicator can give trouble too. You just tested gauge unit if you got full and empty on it. Simply handling the pump wrong can make them misread. The arm swing (AS MOUNTED IN TANK) must match what it takes to get full and empty on the gauge. Possible resistance in the wiring from gauge to pump.
 

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Discussion Starter #10
And where everybody ends up. I'm telling you, if the arm or float is compromised on pump you have to be able to think it out to get it back. The resistor track on pump indicator can give trouble too. You just tested gauge unit if you got full and empty on it. Simply handling the pump wrong can make them misread. The arm swing (AS MOUNTED IN TANK) must match what it takes to get full and empty on the gauge. Possible resistance in the wiring from gauge to pump.
Oh ok Thank you:) So I have noticed when I fill tank up it seems to register way over full on gauge so when it runs out the gauge is at about 1/4 tank. So bend the pump arm down a little I assume then:) I’ll try that:) Thanks
 

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No, bend it the OTHER way. Think about it. You are hitting physical end limit of the arm before you have used up all of the gauge bandwidth. You set the arm to empty NOT full. When you bend the arm up the arm then drops lower to read the lower part of the resistance track (toward zero). You are right now hitting tank bottom with the arm before you are at zero on the resistor track.

You have to hit bottom of tank and the resistor track must be at zero both at the same time, let full be where it will.

If you bend the arm down more you will be running out of gas at 1/2 tank instead of 1/4.
 

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I replaced the fuel pump in my '05 Altima S 2018. The replacement pump did not have the same resistance range for the fuel level arm. The original was 5.6 ohms full tank and 82.1 ohms very low. The current fuel pump tells me I have a full tank for more than 100 miles and when the gauge indicates a half tank it is in my best interest to get more fuel soon.

I have run out of fuel in the Altima once and when I got more gas that day I put in a total of 20.5 gallons from the gas can dose and fill up after driving less than 5 miles. Running out of gas makes for a long day.
 

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If the same pump you should be able to swap the old fuel sensor setup and back to working fine.

Without you giving the resistance numbers for the new pump there is no proof the readers are different.......I never change a pump without a level check before I permanently install it.
 

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Discussion Starter #14
I replaced the fuel pump in my '05 Altima S 2018. The replacement pump did not have the same resistance range for the fuel level arm. The original was 5.6 ohms full tank and 82.1 ohms very low. The current fuel pump tells me I have a full tank for more than 100 miles and when the gauge indicates a half tank it is in my best interest to get more fuel soon.

I have run out of fuel in the Altima once and when I got more gas that day I put in a total of 20.5 gallons from the gas can dose and fill up after driving less than 5 miles. Running out of gas makes for a long day.
Ok wow!! I’ll check this out! Sounds like what mine is doing. I have noticed it’s on full along time!!
If the same pump you should be able to swap the old fuel sensor setup and back to working fine.

Without you giving the resistance numbers for the new pump there is no proof the readers are different.......I never change a pump without a level check before I permanently install it.
Well shoot:( Unfortunately I threw old pump away cause I thought it just needed replaced. I usually never throw parts out right away but the gas smell is why I did:( Thanks for the info tho:)
 

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It's only hearsay until somebody backs it up with numbers matching or not. Why I said it.

The '04, '05, and '06 49 state pumps all call for 80-5 ohm reading on the fuel sensor.

Easily checked with a voltmeter to verify it.
 

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Sounds like the new sensor has a lower resistance range than the old. We might be able to 'pad' it out electrically to make it behave closer to what you need, without having to replace it again, but still need the full/empty resistance ranges to do so.
 

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Yes.

I've added a $1 resistor to a temperature sensor output before to do the same to a sensor that substituted for the original value. Same idea if possible. Need to know what the new fuel gauge readings were, the guy above never said.
 

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Yes.

I've added a $1 resistor to a temperature sensor output before to do the same to a sensor that substituted for the original value. Same idea if possible. Need to know what the new fuel gauge readings were, the guy above never said.
Sorry for the slow response.

I can't find the values for the replacement fuel pump's level sensor but I know they are different than the original. In order to install the new pump I had to put the float arm on the pump after the pump body was in the tank. The original went in and came out without removing any parts.

I chose a non OEM fuel pump because the least expensive OEM ones I found were more than 130 dollars. The one I found was less than 70 and I accept my incorrect fuel level gague as punishment for not getting the OEM.
 

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That can easily happen what with the wonky pricing strategy used on Nissan fuel pumps. Some are reasonable and some are priced to the stratosphere and no seeming logic to it at all.

If a 'universal' pump type was used no wonder the sensor doesn't work right and having to put the arm on after pump is in tank sounds way wrong. Pointing that way.

I know if I was faced with a $400 pump I would be looking at the original pump to determine differences and any modding needed, I have swapped $35 pumps for $400 modules on Ford that had no replacement at cheap and they have worked fine. Haven't had to do it on Nissan yet but that means nothing. A pump is a pump to me as long as the FP range is correct. I generally mod every pump I put in anyway as there are always things I don't like about this or that. The rubber mounting vibration absorbers on them are often contrary to what is needed and I rework them as necessary and no trouble with any one I've ever done.
 

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Discussion Starter #20
So I warranty the pump and I got a new one for O’Rileys. Same part number as last one but completely different looking pump. I fueled up after install and with ignition on I watched fuel level as it filled. It didn’t move for about 6 gallons till I hit the dash and then it rose to full. I just feel it’s in the dash?! Should I have cluster checked or rebuilt? I even tried a used cluster and same thing:( Ugh!!!
 
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