Fuel gauge anomaly ?
 

Hello,
I have a 1993 Civic VX ( purchased in Dec of 2010 w/ 175k on the clock...).
No matter where the fuel gauge is, when I make right hand turns, the gauge "drops" about a quarter of a tank, then slowly resume it's pre-corner position. The Honda dealer says that this is normal ( ! ) I find this hard to believe and was wondering if anyone out there has had this issue and has a solution/remedy for it. I realize that one could just say to replace the sending unit, but looking for less expensive options if one exists.
Thanks,
Douglas

The least expensive option would be to ignore it, and only look at it when it's stabilized. It is normal.

Yep, normal. Happens also when heading up (or down) steep grades. I did what Frank suggested... ignored it, and read only once it's stabilized

For an illustration of why this happens, fill a wide pan about 1/2 way with water. Now tilt it a bit--not so much that the water slops out, but enough to notice. Look at the level of the water in the pan on the "downhill" side. Is it halfway up the side of the pan?

Now tilt the pan the other way, and look at the level of the water on the "uphill" side. Not halfway up the side of the pan, either, is it?

The sender for your fuel gauge is showing you the level of the fuel in the tank near one side or the other. As the fuel sloshes around, the reading changes. Most of the gauges are pretty heavily damped so that they don't react to sudden changes, but if the change goes on for long enough (probably on the order of tens of seconds??) the results will show on the gauge.

Frank's advice is, indeed, the best way to deal with it.

-soD

...it's also one of the initial "signs" that the float-level "pivots" are wearing-out inside the gas tank, causing a much large "change" in signal to the gauge in one (worn) direction than the other (not-worn).

...eventually, the gauge will only seem to "work" when it's full and then become "erratic" as the gas level in the tank goes down.

Thanks everyone for the responses ! I do appreciate your alls time.
Old Tele Man - appreciate the "why" it is happening - had my assumptions as to the mechanics of what was going on, but wanted a more definitive answer... Assuming there is no DIY fix action or mod, the only way to solve the issue is to replace the sending unit with a new one, as getting one from the junk yard would be a crap shoot...
As far as just living with it, I launch rockets into space for a living and allowing an anomaly to go unresolved is well, unthinkable ! :eek: LOL I wouldn't be able to sleep at night ! LOL I will let it ride for now as I am currently on the quest to resolve safety & mpg issues for the moment, but will get around to the sending unit as the car pays me to drive it ! i.e. I also own a 1991 5.0 Mustang ( purchased new in May of 1991 ) and it only gets 17.5 mpg ( was getting 21.5 mpg with the stock 2:73 gears 'till I dropped in a 3:55 gear in the rear... ). I set up an "excell" ( Numbers program on my iMac ) with functions set up such that every time I put gas in the VX, it tells me how much $ I saved NOT driving the 5.0 !! So, the money "saved" pays for tweaks/mods to the car ;)

If it were me, I would just leave it and check how many miles the trip odometer has when it's at about half a tank. Then if the sender completely dies, just fill it when you get to that many miles.

...I agree, that's what *I* would do, unfortunately, we had two other drivers (wife and teenage daughter) who are not so numerically-consciencious about the odometer readings.

...result? $400 to have the float/sender/pump assembly replaced in our '87 Astro Van.

I'd hook up an MPGuino if I were the OP.

My 94 VX did that from day 1 when it had less than 28k original miles in the spring of 2008.

Totally normal and if you replace the sending unit, you are wasting your money.

regards
Mech

Purchased the MPGuino last night. Will get it hooked up asap and enjoy the mpg quest !! Looking forward to tweaking my driving habits !

Anyone know the highest maintained mpg's obtained from any fellow VX owner on this site ?


Sending unit is $51 from partsgeek... Realizing it won't help in the quest for mpg's, I will let it ride for now...

Thanks guys

Try EcoModder Fleet list - EcoModder.com . There's still some searching required (try control-F to find "vx" in that page)...

-soD

basjoos' car is essentially a VX now. I've heard 95+ mpg for that AeroCivic.

A VX should be capable of better mileage than my larger, heavier, thirstier, worse aero, poorly geared 96 sedan.

About the fuel gauge - I see mine change with uphills and downhills, but not for turns, and never as much as you're reporting. Yours may not be completely normal.

Fuel gauge behavior depends on which way the float arm is oriented, tank shape, etc. I've had gauges that moved on accel/decel, and some that moved on turns.

But I've yet to have a gauge wear out the float arm pivots. :confused:

I have seen mine (94 VX) go from 1/3 tank to almost 0 on a Interstate exit ramp where I was going 45 MPH around the cloverleaf.

That's a VX, 94 model year, not some other model that might not act the same way.

Mine would generally stay on the full mark until 100 miles if it was filled completely. When it had stabilized at 1/2 reading, it took 5 gallons to fill.

Don't waste your money trying to fix it, because it will be a waste of money. Many manufacturers have developed methods to dampen the fluctuations in fuel gauge reading, including sending units that are encapsulated with small holes to allow fuel in and out of the sending unit itself. Mercedes used this design 30 years ago.

The old simple heated bimetallic gauges with the resistance wound sending unit as a variable resistance to ground single wire setups will all do that unless you add significant baffles in the fuel tank. Same gauges were used on the original F15 fighters, because they are just about as bulletproof as you can get. Even if the in tank sending unit is shorted directly to ground you just get a full tank reading, with no sparks in the fuel tank, because the voltage to the sending unit is less than 2 volts.

My 1937 ford did the same thing. Shorter more flat tanks make it worse unless extensively baffled.

regards
Mech

I'm new here but have been lurking for several months. And after a long search, I was finally able to find a '95 Civic VX that was in decent condition. I used the search function, but was unable to find a recent thread that related to my problem. Sooooo, since you are the man...

I've read about the fuel gauge problem with this car. So after running the needle as far deep into "E" as I dared to, I refilled... all I could get in the car was 6.05 gallons! Was I just premature in heading to the gas station? I checked the gauge more than once on level ground and didn't head to fuel up until the needle was parked consistently below the 'E" bar. Your comments are appreciated.

Where is the needle after you filled up. It should be solidly above the F mark. If I fill to the first click I have about 1.5 gallons until it comes down to F.

Thanks for responding. I''m pretty sure that it was above F when I filled up; I'll double-check that the next time I fill up. But I did make three attempts to continue filling after spilling/overfill when the pump read just 6.05 gallons.

Additional issues:
1. The upshift light ceases working after the engine is up to temperature (ECU?)
2. The idle is running about 1100rpm once warm (idle control motor?)
3. When the car is still cold, the rpm's seem to be sticking in between shifts (??)
4. Occasionally the engine dies when coasting to a stop (O2 sensor?)
5. Finding a driver's seat.

And of course the transmission is toast.

Thanks

I can't help with most of those. Sorry.

The high idle - there is a vacuum operated valve that may be clogged. Idle Air Control Valve, I think it's called.