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No fuel when gauge still reading 1/4 tank


EricCR
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Has anyone had this problem with their R50s? I already got stranded after running out of fuel. Luckily I had a gas station just a few yards away.

 

When I turn off the engine the gauge needle drops all the way to the bottom so at least I know the gauge is fine. It must be the fuel sending unit but the one for facelift R50s has apparently been long out of production (25060-2W610). The only one that can be found is 25060-1W610. Are they interchangeable? The older one appears to have one extra sensor.

 

Also, does anyone have the link to the service manual or the resistance values for the sending unit? I want to test it first before finding a new one.

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Ive had a similar issue with my 1997 R50.  Its happened about three times now over the past few years where the gauge needle would randomly descend down to empty for a few seconds or minutes while driving and then correct itself. My gauge functions a bit differently, remains at fuel level once engine is shut off and does not drop to the bottom. 

 

But I know it will completely go out one day since its already started acting up. I should also mention, my low fuel light does not get triggered in the dash (bulb is working) so I assume its related? 

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Mines been this way since I bought it about 6-7years ago!

it had just under 1/4 tank when I bought it. I test drove it for quite a bit so it was warmed up and went through the gears rigorously including 4wd.

All checked out so I bought it and headed down the way. About 5 minutes later it started sputtering really bad and I got P’OD something bad and the seller wasn’t answering his phone which made me even more upset.

He did call me back and ended up following me to the gas station to fill it up. Never a problem since now that I know that when I’m hits the 1/4 line, I better start looking for fuel. 
I now use the mileage meter as my gauge and have a Jerry can on board just incase!

 

My guess is the fuel warning light it tied to the arm placement and nothing else. Mine never comes on except for the few times it’s done as the previous post mentions where it will drop to the bottom while driving for a period of time and come back up. While it’s down at the bottom, the light comes on. Otherwise, I never see it because my truck is slap empty at right about 1/8 of a tank on the meter.

still get between 325-350 miles per tank regardless as long as I’m not hauling anything.

my gauge arm also never goes above 3/4 of a tank either. 
Just something over had to adjust to when driving it-which unfortunately is extremely rare!

Edited by 03TroutFinder
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So it seems like it's common for them to act up. I'll attempt to troubleshoot/fix mine and report back.

 

I'm planning to take it out of the tank this afternoon and check resistance.

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Aight, so I took the sending unit out, tested it and of course it's reading perfectly fine. Life just couldn't be so simple.

 

According to the service manual, an empty tank should read around 80-83 Ohms:

image.png

 

And this is what I got (took the picture as the multimeter was alternating between .2 and .3, hence the weird decimal). All other values going from empty to full read exactly as expected:

2022-10-24-13-19-20-093.jpg

 

So now I know the culprit is somewhere else. Before taking the cluster apart I found this video, which describes very similar issues with other Nissans and since I've had to fix plenty of broken solder around resistors in the Pathy as well as other Nissans in the family, I'm pretty sure this is the fix. It looks like our R50s don't have a separate module to process fuel level signals and it's all handled by the cluster's mainboard (aka "combination meter"). I'd have preferred a separate module so as to not to tinker around the cluster, but oh well. I'll keep you posted.

 

 

 

 

Edited by EricCR
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It is common. Both my R50 and my dad's R50 had these issues during ownership. Mine would stop at about 1/2 tank intermittently. Sometimes it would read accurately for the entire tank. They act up. The R50's were both VQ35DE vehicles. Not sure of the cause or the fix, both vehicles were sold with the problem still there....

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It's fixed.

 

It's not so complicated but there's one big pain in the ass: You have to remove all 4 gauge needles which means you'll need to calibrate them later.

 

  • Step 1: Remove the instrument cluster. This is the easy part. Follow this video: 

 

 

  • Disassemble the cluster. There are no screws, just plastic tabs everywhere. Start by taking the clear plastic cover out first, then the black plastic frame. It's all pretty straightforward. You'll end up with this:

2022-10-24-17-43-34-198.jpg

 

  • Now you need to take the needles off. I strongly recommend the 2 spoon method. Google how to do it. Don't worry about marking their position or anything, no matter how careful you are, you will have to calibrate them so don't waste time, just take them out.
  • Once the needles are out, you can pry off the cluster graphics and put that aside.
  • Turn the cluster around (facing the back side - be careful not to place the exposed front on a hard surface!) and bend the 2 white tabs holding the circuit board in place. Pull it straight out, towards you. Be careful with the odometer's LCD as it's connected with long, thin leads which could bend or break. In mine it stayed in place but if I had to do it again I'd remove the LCD first.
  • With the circuit board exposed, you'll need to follow pins 17 and 23 and find any resistor along the way. These 4 were suspicious (labeled 161 and 181). No matter how closely I looked, I couldn't see cracked solder but I added some more while also reheating the existing solder. I also inspected all other resistors and retouched a couple more, knowing how ****** they are in Nissans and how hard they are to find.

Inked2022-10-24-15-15-46-982.jpg

 

  • Once you finish with your soldering/inspection, it's just a matter of reassembling everything back together and testing. As for calibrating the needles, it's better to do it with the cluster plugged in and the key in ignition (waaay easier if engine is cold).
  • Turn on the ignition and lightly push in the speedo, tach and temp needles making sure they are touching their resting posts. Turn off and on the ignition a few times to make sure they don't move from there (when they receive power, they will come alive and try to jump to their zero position). Don't install the fuel needle just yet.
  • Here comes the headache: To calibrate the fuel needle you'll need an ohmmeter to calculate the fuel in the tank (unless your tank is full or completely empty, if so just place the needle accordingly). Disconnect the large plug (4 contacts) from the fuel sending unit and read resistance from terminals 2 and 3 (diagonal to each other). A full tank is ~5 Ohms, empty is ~83. Considering the resistance changes linear (more on this later), every 1/4 mark would be in ~19.5 Ohm increments. Example, if you have 3/4 tank, resistance should read about 24.5 Ohms (5 + 19.5) Alas, according to the service manual, 1/2 tank should be ~33 Ohms, which means the reading is in fact not linear (otherwise 1/2 would be (5 + 19.5 + 19.5 = 44 Ohms). I assume this is to account for the tank shape (narrower at the top). Taking that into account, it's better to consider the calculations separately, one for full to 1/2 and another for 1/2 to empty. If so, 3/4 tank would be 19 Ohms (5 + 14), 1/2 tank 33 Ohms (5 + 14 + 14) and from then on 1/4 tank 58 Ohms (33 + 25) and finally empty 83 Ohms (33 + 25 + 25).
  • This is a good time to test if you actually fixed the issue. Either disconnect the fuel sending unit plug and feed it 80+ Ohms (pins 2 and 3) or unscrew the whole fuel sending unit with the wires still connected and pull it out slightly, just enough to allow the float to drop to its lowest level. The latter is easier but super risky given that you have your fuel tank exposed and the car in ignition. Do this at your own risk.
  • If the issue is still not fixed, then rinse and repeat, check, reheat, resolder resistors. If that still has no effect, then your problem is elsewhere.

 

Hope all this helps someone at some point. Surprised nobody had attempted to fix it if it's that common.

Edited by EricCR
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4 hours ago, EricCR said:

It's fixed.

Very nice write up and investigating. It's refreshing to see a post from a Pathfinder enthusiast. These lift questions from users that can't afford a 4runner are getting old. 

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Side note: While I had the cluster disassembled I thought of adding some metal rings to the gauges. I did it to my BMW E39 a long while ago and ended up looking great so why not do the same with the R50?

 

Here's an example (this is a Maxima):

s-l1600.jpg

 

I took measurements and contacted a guy on eBay and since it's the first time he will fabricate rings for an R50, he's going to send me the first set to test. If they work then he will create a listing for them. Just in case anyone is interested. I will definitely create a new post with pictures once I install them and a link to the eBay listing. These will only work on 2001+ R50s (VQ35), not <2000 and not QX4s. Those have different clusters.

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  • 2 weeks later...

Hey new member here! Just recently purchased an R50 this week and I had to tackle this exact problem! My fuel level sensor was working correctly as well but I think it's a win/loss no matter what issue you run into. The fuel level sensor looks like an expensive part while the instrument cluster is technical but cheap. 

I will say my fuel tank seal did NOT want to go back in place. It had stretched out so much I couldn't fit it back in the grooves. I was looking for the fuel tank seal online and was struggling trying to find one that wasn't outrageous expensive.

There is one on rockauto and I believe I found a cheap part #. The Carter PTS2043. Anyways 

I took apart the instrument cluster and you really want to just take everything apart. The LCD screen just pulls straight up. Wiggle it out if you need to. I have always been terrible at soldering, especially electronics but I tried this and I believe I fixed it on the first try. I focused on the resistors you mentioned while also touching up others. 

Multiple of my bulbs in the instrument cluster were out. They are the Toshiba v-2. A quick Google search shows that you can pull the bulbs out and replace them with #74 mini bulbs. (2-pack at AutoZone for $6). I ended up grabbing them with pliers and destroying 2 out of the 4 I was replacing. A YouTube video that shows using a thumbtacks to remove the bulb just ended up breaking the plastic holder. I may end up switching to LEDs in the future but this worked out for me since I wanted to complete the project that day.

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Glad you fixed it. Not sure if you did it before finding my post or after, but in any case I hope it was useful.

 

Yeah, if the problem is the fuel sending unit then you'll run into issues with the o-ring, rusty bolts, spilling gas in the carpets (no matter if you released fuel pressure, there will be at least a slight mess). If the problem is the cluster, you'll run into needle calibration issues and there's a big risk you mess up the electronics. It's indeed a win/loss.

 

The service manual recommends replacing the fuel sending unit o-ring every time you unbolt it. IMO that's a bit overkill but after ~20 years it may be a good idea to get a new one anyway. Mine did begin leaking just so slightly and only when the tank was full. I vacuumed, cleaned and reseated the o-ring and no more leaks, but I ordered a couple off eBay, genuine Nissan (https://www.ebay.com/itm/274508079289). $22 seemed alright to me. There is a Doorman set with the 6 bolts that hold the pump/FSU in place too.

 

As for the cluster bulbs, I tried pulling one out too, it wouldn't budge so I left it alone. Don't know if you noticed but there are 2 different type of bulbs: black and brown holders. The black ones are smoked (I'm guessing to make them dimmer) and light up the gauges. The others are clear and go behind the turn signals and other indicators.

Edited by EricCR
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I fixed it after your post, just a day or two ago. It was super useful, although I haven't calibrated the fuel gauge yet. I figured I would fill up the tank to full and calibrate it that way. But when I removed the fuel level sensor i noticed the gas was very low and when I put the cluster back together it had the "low fuel" symbol lit up for the first time. This makes me think that the issue has been fixed, but i will confirm later on.

I saw the smoked bulbs but just decided to replace them regardless because I didn't know where to get smoked bulbs. Though maybe giving them a light coat of black spray paint would smoke them? Either way the new bulbs light up the cluster way better than before so I have no complaints.

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The only way to get those special cluster bulbs would be via part numbers and a Nissan dealer, but don't bother, I switched all of them around and it's basically the same thing. They are not special at all.

 

And yeah, I feel you. I just filled up and the needle went a couple mm above where I would've wanted to see it. It has since gone down but I need to adjust it a bit after filling up again. For now I'm gonna wait until it's below the 1/4 mark to see how it behaves.

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Okay so I just filled up the tank today and the gauge went to full! Success! But wait... uh oh... My speedometer isn't moving anymore! I wonder if I was too rough with the needle. I really don't think so. I'll try again tomorrow and see if I can get my speedometer to move again. Also my shifter light is off and I've tried looking at other posts but i don't see the bulb where others have posted. I don't see it at all near the P or beside the R.

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Was the speedo working after you reassembled everything back together and suddenly stopped working? Or is this the first time you actually drive the car?

I hope it's something easy like readjusting the needle but you may have gone a bit overboard with the soldering iron.

 

Take a look at the base of the needle, the round center part. It may be touching the "graphics" faceplate if it wasn't reattached properly. There are a couple of small metal tabs that prevent that graphics layer to bend outwards (they are right under the needle centers) and if that's loose it may be exerting friction on the needle. If you pressed on the needle too hard it may have gone too far down, also making contact.

 

I doubt you broke the servo actuating the needle unless you were really rough on it. My bet is that something is interfering with it, but try to find it quickly because if you keep driving the car the servo may fail as it's trying to move the needle.

Edited by EricCR
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  • 1 month later...

Proof of the fix working (it's been about 3 times already it goes to Empty, wanted to make sure the fix was consistent). In 2 years of owning the car, I never saw the low fuel idiot light until now:

 

2022-12-11-12-33-41-081.jpg

 

I also got around to installing a set of cluster rings:

DSC04271.jpg

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  • 3 weeks later...

Damn, was hoping to find some answers in this post for my issue. My 97 starts sputtering and dying a little before the needle hits E, gas light has never come on. I can also only put in 15 gal. 

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