I filled up my tank a few days ago and have not put much mileage on it since. At that time my “mileage/range to go” reading was in the usual range of about 375 miles (to go before empty).
When I started the car yesterday a.m., my fuel gauge needle was pegged at zero (or below) and the “low fuel” warning light was on, although the mileage range reading was still well over 300 MTG. Barring a fuel leak, which would have been very noticeable, I knew I couldn’t be out of gas…I checked this assumption by heading over to nearest gas station and topping off…it was just a gallon or so short of full, as expected.
So generally unconcerned about running out of gas, I drove around as normal for the day, maybe going about 10 miles or so and turning car off/on/off maybe three times? Then when headed out to DMS last night, everything was fine, I’d need was back up to full and has remained there since.
After reading up a bit, I gather there are three things that can affect fuel gauge reading and result in what I experienced:
Instrument cluster issue (least likely, as I understand it)
The electrical circuit involved. (also not very likely?)
The sending unit (part of the fuel pump module). My take is this is the most likely culprit.
So…wondering:
-1) What might account for intermittent (1 time so far) nature of the issue? Is this something that is a forwarning of more occurrences or a final failure?
-2) How concerned should I really be if gas gauge does finally fail, i.e. needle reads empty permanently? Assuming range/MTG reading is generally accurate, is that good enough if I use it to time fillups when I still have plenty of range? That reading seems independent of what the fuel gauge is indicating, but I don’t understand how that can be, actually…something has to feed information about tank status to whatever calculates the range/MTG, right?
-3) With my car (2007 Toyota 4runner 6cyl), I think I can access an opening to the gas tank (probably where the fuel pump is) and fuel sending unit via removing my back seat. But if I understand the Youtube vid this would be for inspection only, and I’d still have to drop the fuel tank if I needed to replace the sending unit, if that is indeed the root cause.
The Most likely issue is the sending unit attached to the fuel pump or near in the tank. (this differs by manufacturer over make, year of manufacture, metal or plastic tank etc.) If this were a 2007 German auto - accessibility for testing and or replacement would be fairly easy due to the access panel above the fuel tank / sending unit.
Looks like your fuel sending unit is Part Number 83320-60440 with a cost of $131.51
Thanks Tom. What’s your gut feel on how concerned I should be about this one-time occurrence, or if it becomes regular (every few weeks or months or whatever) or chronic/permanent?
My particular year/make/model has “easy” (remove back seat) access for inspection/testing, but not for replacement, unfortunately :–(
Marshal, no idea why Yota would not make it only half accessible but ok…
How long can you “live with it” is the real question?
(If this was a military aircraft like a Hooker, where you could thump the tanks and knock the moisture off the sending units-, problem solved)
My only real concern is running out of gas…kind the whole point of the fuel gauge, I guess.
As long as the range/mileage-to-go reading is accurate over time, i.e. it accurately tells me when I have ~50 miles of range left, I wouldn’t be very concerned with the actual needle not working.
For right now, it’s not an issue as the gauge is currently working as expected.
Let me know when you guys are going to meet. I have the same issue with my 2006 4Runner except my fuel gauge stays at Empty. This is not unusual for a 4Runner. Search for my post on this exact same issue from sometime last year and you’ll see a couple YouTube videos posted in the thread on 2 ways to replace everything.
Right now, I track my miles using the odometer. I really want to get it fixed though. I talked to @skyspook about it at one of the potlucks and we both agreed the best way would be to cut the opening under the rear seats to make it bigger using hand tools (since there’s fuel right below) and then use something like JB Weld to close it all up when done. It’s too much work to fully drop the fuel tank.
Absolutely two is better than one! Your research (plus @jast 's) and conclusions and reference vids are pretty identical to mine.
Speaking for myself, I’d be nervous cutting new holes anywhere and hoping I could restore to previous condition correctly. While I tend to agree dropping tank is a bit of a PitA, at very least if I can’t get back to status quo I can always then tow somewhere if absolutely needed, i.e. if Tom or Allen W. isn’t around :–)
I think 1st thing is to determine if the sending unit (floater) is indeed the culprit, which we can do by removing the back seat and accessing unit from the inside of car. Or so it seems when the experts do it on Facetube :–) I think I read on a forum where wiping the right area with some cleaner (isopropyl or brake cleaner) may remove some of the carbon whatever that sending unit creates or builds up when it oscillates back and forth over time.
Let’s do it then! I say we make sure someone is there that understands all this stuff so that we can consult them as we explore/work this in tandem. What days are best for you?
Without doing any actual research, just my gut feeling honed by minimal experiences, if the light is working, but the gauge isn’t, it’s not going to be a sender problem (they typically use the same sender to my knowledge). That means I would expect to find the problem in the instrument cluster (as noted in tailend of the video I linked in Jmeinel’s thread, this is “known” in 4Runner circles), wiring between sensor & cluster, etc.
I will suggest in any case testing, testing, testing before cutting anything or pulling anything as involved as a fuel tank. Get the new (or new-to-you) unit and use the portal in the floor to unplug from the tank, plug into the replacement, manually manipulate the level, and see if your gauge and/or light respond as expected. Do be advised that fuel gauges/lights in this era transitioned from “days of yore” when there was a direct correlation of float-to-gauge and you could literally watch the gauge move while manipulating the float, to a “modern” version that applies electronic magic to “even them out” (apparently once we applied lights and/or warning bells, people got edgy about them repeatedly raising the alarm during a turbulent drive on the cusp wherein the sloshing level would cause the threshold to repeatedly be violated, so they got the lithium treatment).
Some days I miss the ol’ “reserve” levers, though I personally preferred the cable operated gauges for their raw mechanical approach to automating driver intimation.
~a guy who remembers when using a stick found on the side of the road was a “valid” method of determining fuel level in an automobile/motorcycle/tractor fuel tank
I hadn’t seen this reference anywhere…ima check-in of Toyota forum and see if there is any further tribal knowledge concerning this. Thanks…
I get the feeling you (nor I) are in a major hurry, so per previous comment, let me do a little more research. I’ll help you no matter what, if for no other reason than it will almost certainly lead to better understanding on my part.
Whenever we decide, if we need to have a more experienced person there as a safety net, I’ll just be available when they are. If 1st goal is just to do what is necessary to access tank hatch for inspection and testing, that sounds like about an hour or so for one vehicle including getting everything back in place, so 2.5 hours at DMS.
For now, I am going to sit tight and see what further symptoms or problems appear regarding this for my car over time.
@jmeinel: anytime you decide you want to try and investigate and diagnose your particular issue, I am willing to come and offer whatever help I can. I’ll at least gain some experience with back seat removal and such, and hopefully also facilitate whatever you needed doing as well.
In the “old old days” car troubleshooting days one would move the cable to move the indicator.
pre can-bus when things required actual troubleshooting without a diagnostic tool, one would earth the lead to the float and the indicator would read full.
Marshall I predict a 7am Sunday or Monday in your future.
