I have the G35 Sedan and been having issues with the fuel gauge as many have.
I replaced the sending unit on the drivers side and have ordered the fuel pump assembly 2 or 3 times now (I lost count) for a "2005 Infiniti G35" and keep getting an assembly different than the one in my car.

The area where the fuel pickup line connects to the pump inside the tank is totally different between the new pump and the old pump.

All the listings say the pump fits a 2003-2007 so out of curiosity I looked up a pump for a 2002 Infiniti and the one that came up is just like mine....

My pump looks like this one:

"edit" I think I am wrong calling the line a pickup line...The black line in the picture isn't a pickup line is it? Is it a return line or what?



I guess my question would be: Did they carry over the parts on the 2005 cars from earlier ones or did somebody maybe put the wrong pump in previously maybe?
The thing with assuming somebody changed the pump in the past with the wrong is the lines are different inside the tank unless he changed them also.

Maybe I need to use the new type pump and also change the pickup lines in the tank also??

I am not sure what to do...

Also, when I remove the fuel pump and sending unit (passenger side) with the key on the gauge reads correct even though it's only getting a reading from the other sending unit. I thought with the pump out and plugged in & key on I would see a difference on the gauge by manually moving the sending unit float by hand..... it made no difference on the gauge.

- The tank is half full -
Before I removed the fuel pump the gauge read 3/4's of a tank
After I removed the fuel pump and with it disconnected the gauge reads 1/2 tank (which is correct)
With the pump out but plugged in and the key on it goes back to 3/4 tank reading..... Moving the sending unit float arm up or down makes no difference.
I am thinking that means the pump sending unit has a short or grounding problem?

 

The picture looks like my 04' and 05' G35x pumps. I have 2 laying in the garage just like it. The black line siphons fuel from the driver side to keep both sides equalized. It is connected to a venturi on the side of the pump body. Fuel comes out of the pressure regulator through the venturi to make a siphon but has a check valve to keep it from siphoning when the tank is full on the passenger side. The tank has a hump in the middle and only one fuel pump so this is the only way to keep the fuel equalized. While you are in there make sure to change the fuel filter. It is the whole lower section and not fun to change later. They cost about $21-$22 on ebay. I'll ohm check my 2 fuel level floats and let you know the results.

Edit: another tip - if you are replacing the whole fuel pump assembly with another unit just unhook the venturi from your old one and install it on the new unit. The black plastic line will probably break if you try to remove it and then your in lots of trouble.

Edit: Empty 84.3 ohms and Full 3.4 ohms

 

Ok, I didn't know it drew fuel from both sides. I was thinking there was a tube that just let it equalize on it's own by flowing through somewhere.

Thank you for checking the resistance for me, where do I check that exactly? On 2 of the prongs where the plug goes on or on the pump itself?
There is a screw with 2 wires attached right next to the sending unit part.....

I am assuming best to check where the plug goes on, would you know which 2 connectors I would test?

 

I just tested it right off the level sensor wires but I can OHM check them to the pins on top tonight if you need. One of the two pumps I had in the garage must have had a dirty level sensor because it would read open in spots as i slowly raised the level. The other one went down in ohms towards full consistently and never opened up. I would guess this is the problem most are having with them.

 

The few people I personally know that had this problem ended up solving the problem by having their cluster repaired. I believe they found someone on ebay that they sent it to and he shipped it back a few days later.

Your problem may be different but it's worth a shot in checking out.

 

It combines the readings from both fuel sending units to determine how much fuel you have. I would look up the cluster self test before you start messing with your fuel pump and sending units. The temperature and fuel level should go to the halfway mark during this test. If they don't then your cluster needs to be fixed and it's from solder connections.

 

I'm not sure but i think the bad resistors won't cause the fuel gauge to fail the self test. I think the resistors are in the sensing circuit not the motor drive (i could be wrong though...). The self test just proves the stepper motor can put the needle in the designated spot. You do that test to make sure your gauge/motor works. If the gauge works and you still don't display fuel level correctly, it's down to sensing the correct level. That's when you test the sending units according the manual by testing the resistance over the range of motion of the floats. If those both read normal, it's almost certainly in the cluster resistors. My problem was solved by touching up the resistors in the cluster.

My car needed the needle to be in a slightly different position during the self test compared to what the manual says. If I put it in the center, the gauge indicates well over full when full and about 1/4 when empty. It was roughly 1/4 below mid-point when i did the self test but I chalked this up to the problem with the circuit so I put it back in the middle during reassembly. But then when everything was back together and I filled the car up, the gauge indicated way over full. For anybody doing their own cluster disassembly and repair, I recommend you perform the work when you know the level in the tank (like full or preferably empty because that's where they read incorrectly) so you can be sure that after the repair you can plug the cluster in while still disassembled and confirm the fix before you put the whole cluster back together. If you don't know the level, you may know the problem is solved like I did because it could read something other than half full but I had no idea that I added an offset to the reading by my needle placement. And it's enough of a pain to take it all apart again that I'm just living with it even though it bothers me to look at it like that.

But I do agree with coffee that everybody should start with the fsm and do the sending unit tests and the gauge self test and read the whole fuel gauge problem - detailed thread before trying to replace any parts. It will save you time and money.

 

Looking for a new fuel pump assembly but the ones on the market have a few differences that cause it to be near impossible to install.

1. The size of the original pump is so much smaller than what is currently on the market.
2. Fitment issues- the black gas line that connects my tanks can't connect to the nozzle on the new pump due to its shape. Also the way the ports face are opposite to what the original fuel pump layout is.

Thats the one that is "compatible with my car"

Anyways spent over 3hrs trying to install the new one and with no luck, here i am.

 

^^^
Where are you obtaining the parts from?
If they are not genuine OEM that may be your problem?
Visit a Infiniti parts department to observe the correct one

 

Looks like a 2007 up fuel pump assembly. Totally different so I have no idea if that will even work or can be made to work. I would just get the right one for your year and be done with it.

 

We had the same problem a couple of years ago. The pumps you are getting are for a coupe not a sedan. And for the life of me I don't remember where we got the correct part. Here's a used one on ebay that you could take a chance on or buy a new factory unit.

https://www.ebay.com/itm/2003-2004-2...cAAOSwO-RdsMuH

 

Ok, Since I never listen to advice, I replaced the fuel pump / sending unit on the drivers side at considerable cost and it didn't fix the problem.
So now both sending units have been replaced so I guess it is the gauge.

Found a youtube video on how to remove the gauge cluster so what do I need to do then? Replace the fuel gauge or is there something that can be fixed that is a known problem like a wire or soldered connection?

 

^^
Wiring harness!

 

Yep, next step is to unplug the dash, unplug the fuel pump, check continuity on the wires between the two.

 

Ok, Next step is too check wiring harness.

With my disability it was easier to rule out the sending units first because they are so easy to physically change, it's not that I didn't believe everyone's advice. I just wanted to do what was easier for me first. The next is going to be harder for me to do.