Scotty,
We have a 2008 Toyota 4Runner, just bought recently so no history. 110k and seems in pretty decent shape. The fuel gauge has started reading incorrectly. Usually won't get past 3/4 full even when full, and goes down to empty before it's used a half tank.
We're using the trip odometer to track gas usage but I wanted to fix the gauge if it's possible to do it cheap.
Interweb legend suggest using something like Techron or another product might clean up the slider on the sending unit and get it working reliably again.
Have you heard of this possible fix? I'm going to try it, just wanted your thoughts and suggestions for a better additive if there is one.
Thanks!
The fuel gauge has started reading incorrectly. Usually won't get past 3/4 full even when full, and goes down to empty before it's used a half tank.
That sounds like the float is sinking. Replacement is the only way to fix it. (Even if the problem is the electrical part of the sensor it's highly doubtful that a fuel system cleaner is going to make any difference.)
Thank you.
@chucktobias Well, an update. It's anecdotal evidence to be sure, but the darn thing started working again after a dose of Techron and a couple weeks driving around town. We'll keep tracking the fuel via the trip odometer as it may be a flukey thing, but wanted to follow up.
@pablo-picasso Sound like you might have gotten lucky! I suppose if there ware a very small amount of varnish on the sensor the Techron may have helped, though it would be the first time I've seen that happen. You'll have to see if it lasts.
@chucktobias I thought the float part was a form of very light plastic and it couldn't really "sink". The only modern-day fuel pump I've handled though, is my uncle messed up a fuel pump, and at the time 14-year-old me came up with the idea of splicing the old fuel pump assembly that didn't work, but was otherwise intact onto the new fuel pump that he damaged. If my uncle had purchased another fuel pump, he would've not gotten anything for doing the job. Lol. The fuel pump was the same price as what he was charging.
That spliced fuel pump worked great, until they totalled it a few years later. Haha.
@justin-shepherd Usually the stuff I'm working with is so crudded up with age there's really no choice but replacement when the fuel sending unit goes bad.
@justin-shepherd Also the really old stuff (like Ramblers) have a metal float that can develop leaks and sink partially or completely.
@chucktobias That might make some sense, actually. How long did they do that? That might make some sense. Suddenly, the gas gauge in my '79 Pontiac now reads full, and I know there's not a full tank in that car. It took a year to install, I still have functional use of only one hand.
@justin-shepherd Not sure when the switch was made from metal to plastic floats. However if the float sank you'd have the opposite effect, the gas gauge would never read full.
Years ago Ford issued a Special Service Message regarding slow to respond/erratic fuel gauge readings do to contamination of the fuel sender card.
They recommended using Techron® Concentrate Plus Complete Fuel System Cleaner. Let the fuel level get low and add a bottle and then fill the tank.
It said to do it on 2 consecutive fill ups and it should clean up the fuel sender card
So Techron has been proven to work just like it worked for you
@jack62 Interesting, a little like cleaning a scratchy pot in electronic gear. Just goes to show no matter how long one deals with this stuff there's always a new wrinkle to learn.
Had the identical issue on my 96 Tacoma last year. I used a large Techron with only 10 gallons gas and drove the truck low and filled it up again. The gauge still wouldn't report above 3/4. However, after filling up the 3rd tank the gauge suddenly read full again and it's been fine since then.