Fuel Gauge isn't steady

[Amnesia]

Hey all!

I'm hoping someone has been down this road before & has some advice for me. My fuel gauge has been acting up for almost a couple years now. It used to be nice & steady, but one day it started to fluctuate a lot when the vehicle is in motion. The rise & fall of the needle corresponds with turning, vehicle attitude, and apparent fuel sloshing.

I finally broke down & replaced the fuel sending unit, because I had heard that it had a "resistor" in it that dampened this action. I finally got around to swapping them out yesterday and no joy. The problem is still the same.

I wonder if our tank has internal baffles in it that may came loose, but I don't hear anything odd going on inside. Or maybe, the "dampening resistor" is part of the instrument cluster. :confused:

Anyway - Hopefully someone on here has some insight they could share!

[H3_VX]

Hey all!

I'm hoping someone has been down this road before & has some advice for me. My fuel gauge has been acting up for almost a couple years now. It used to be nice & steady, but one day it started to fluctuate a lot when the vehicle is in motion. The rise & fall of the needle corresponds with turning, vehicle attitude, and apparent fuel sloshing.

I finally broke down & replaced the fuel sending unit, because I had heard that it had a "resistor" in it that dampened this action. I finally got around to swapping them out yesterday and no joy. The problem is still the same.

I wonder if our tank has internal baffles in it that may came loose, but I don't hear anything odd going on inside. Or maybe, the "dampening resistor" is part of the instrument cluster. :confused:

Anyway - Hopefully someone on here has some insight they could share!

I can't really help you out on that yet, but I've noticed that whenever I fill up it takes a while to actually show that I put any gas in it. I know my Isuzu is not a Lambo, but for a car that originally cost $30k or more it has some issues that should not happen in a vehicle that expensive. Don't get me wrong though, I'm in love with the thing.

[VXobsession]

Mine's been fluctuating since I've had her.......turning sharply to the right REALLY drops my gauge, especially if I'm already low.

[vt_maverick]

Mine's been fluctuating since I've had her.......turning sharply to the right REALLY drops my gauge, especially if I'm already low.

+1 - Best (and by far the cheapest) solution is just to reset your trip meter at each fill-up, then learn your VX's average fuel economy and judge by that.

[PittVXr]

I consider my fuel gauge to be a "rough estimate" of how much fuel I have left. Going up and down hill can cause it to move almost a 1/4 of a tank. I just do what vt maverick suggests, reset the trip meter at each fill up and stop at the gas station every 200 miles. Yeah I get 10miles per gallon....

[Scott Larson]

You could have a bad ground strap somewhere, just a thought...:confused:

[samneil2000]

I usually fill up at 250 miles and get 16 gallons or so. Not too bad considering I'm running 33 inch MT tires.

[Buffy]

Mine does the same thing. I was considering replacing the sending unit, glad I didn't now.

[Amnesia]

Thanks all for the input. Yeah, I always reset my ODO & use the gauge for a ball-park estimate. It's really pretty accurate when it gets down below 1/4... Thing is, it use to be rock solid & steady. Then one day, it got the floaties! (Like the baffles in the gas tank were removed... asssuming it has internal baffles... baffles me.)

I just finally got tired of watching the needle bob around, and so I'm on the hunt now! I lived with the CEL for most of it's 211,000+ miles & I just recently got that to go away. (Or maybe it burned out?!) lol

Anyway - Still looking for a solution. I'll have to maybe go on a ground strap hunt and see if that helps. In the meantime... If anyone needs a fuel sending unit, I have a spare that I could cut you a deal on!

[tom4bren]

The dancing fuel guage is typical. I just consider it an added entertainment aspect of the VX.

When Boy is driving it, I ask him if he needs gas. His usual response is no ... I've got 1/4, 1/2, 1/4, 1/2 tank.

[VXobsession]

I actually get about 300 miles between fill-ups, sometimes a little less, depending on what kind of driving I'm doing. I noticed the harder and faster I drive her, the better gas mileage I get....yes, I know, that doesn't sound right but it's true. If I'm just farting around, driving the speed limit and being courteous, she sucks up the gas like she's starving for it. My fiance' is a mechanic and he hooked up his fancy expensive scanner to her while I was driving one day. He had an explanation for it, it was right there, on the screen, why she gets better gas mileage the harder I drive her........I don't understand it necessarily, but who actually understands that mechanic language anyway...

[Amnesia]

OK - I discovered that the fuel gauge itself can be replaced w/o replacing the entire cluster assy... For about the same price as I paid for a new fuel sending unit. (Didn't fix my dancing fuel gauge.)

So who wants to be the guinna pig & try this out? $88.55
Here is the p/n & link: 8-97211-467-0
http://myisuzuparts.com/

Then go here to put the p/n in to determine pricing: http://isuzuparts.com/partscat.html

C'mon, I already blew roughly $80 on the fuel sending unit... :)

[vxnewb]

I had the exact same issue with my 01. It actually drove me nuts, every time I drove it, thats what I stared at. I did a-lot of research on the net on fuel gauges, and found there is a resistor tied into the gauge to damper the quick movement of the sending unit. So I ordered the new Fuel/Temp gauge from Merlin 4/9/13, he informed me it was on back order. I received it 7/30/13. I installed it, took very little time to do so, I also changed a couple bulbs out in the dash while I was in there.

After 2 full tanks, I can confirm that it is fixed!! Every corner I turn, the gauge stays still where it is supposed to be. No more erratic gauge!

Any questions go ahead and ask

[Mile High VX]

Looks to be about a $100 fix...

[vxnewb]

Looks to be about a $100 fix...

yes sir, I can't remember exact price. it really surprised me I had forgotten all about it, until I got the package 4 months later lol.

[jasonm621]

My fuel gauge wouldn't fluctuate but would work intermittently. Finally just quit working and the past year the fuel needle has been pegged on the "F" The low Fuel light works just fine though so im assuming its the gauge that has crapped out on mine as well. I use the ODO method and can accurately predict when the fuel light will come on (within 20 miles). Especially in the summer months when there isnt as much ethanol in the fuel and the idiot 2WD drivers hitting the snowy hills clogging up the city streets for the 4WD people who really should be on the road... I would like to know a way to diagnose the situation instead of throwing $200 at the situation for both parts. Especially since it isnt really an issue that bothers me...

[hughesdt]

I too have a dancing fuel gauge. And like others it quit working on the full side, but the low fuel lamp continued to work. And of course mileage method is always in use. I finally replaced the sender with the high hopes that it would fix the dancing fuel gauge with no joy either.

Jason, I'm sure that you are correct, your dash gauge is bad. I had the temp gauge do the same thing. I found out that they where sold as a pair and back ordered. So I took it apart, unwound the magnet wire, found the break and wound it all back together. Worked! Since then I have seen a lot of Rodeos with the same or similar gauges, I'm sure the fuel gauge from a junk yard Rodeo will work.

VXNewb, Do you have a picture of the back side of the fuel gauge that might show an added resistor, or more likely a capacitor? Wondering if it is a mechanical dampening that wears out, or if another component was actually added.

[vxnewb]

VXNewb, Do you have a picture of the back side of the fuel gauge that might show an added resistor, or more likely a capacitor? Wondering if it is a mechanical dampening that wears out, or if another component was actually added.

sure

[hughesdt]

Very nice, now I have a reason to pull my dash apart and change my Power lamp and compare my gauges against your pictures.

THANKS!

[vxnewb]

I thought about trying to find some caps and resitors that were the same, and solder them in then reflow the board, but now that its working fine I really dont want to take the new one out to test lol. If someone wants my old one, id be more than happy to send it out....

[Baldwin]

i had this problem. replaced the fuel guage and it's been great for 10+ years now.

[longiotti]

if the fuel gauge moving everywhere is a resister issue then you should be able to solder in a new resister. I wander if it is the one that connects each side of the fuel gauge poles?

[vxnewb]

if the fuel gauge moving everywhere is a resister issue then you should be able to solder in a new resister. I wander if it is the one that connects each side of the fuel gauge poles?

Sending my old one out to Dan (hughesdt) today. I believe he is going to attempt to fix it. I'm sure he will keep us posted!

[eternal21]

n/a

[hughesdt]

Sorry I didn't get back any sooner. The 3 that I looked at all look identical. Have seen the one in a rodeo as well, and can't tell the difference. So far I can't figure out why one will dance and the next will not???

[bartmanS4]

Are you sure the troubles are in the gauge display and not the float/sending unit? I ask this because I would always suspect a mechanical assembly before an electrical one. After I swapped my ECU my fuel gauge was reading incorrectly, it stayed at full for a while and never went all the way to empty more like 1/8. I ended up pulling the fuel float assembly out of the donor car and once installed the gauge read correctly. The float simply moves the wipers on a variable resistor as it goes through its travel. Very possible the resistor is dirty, corroded, or broken.

[tom4bren]

A consistent incorrect reading will probably be your sending unit. The dancin' needle thang is probably electrical. There should be an RC circuit to dampen the signal to reduce abrupt changes in the reading. The RC circuit could be at the sending unit or at the guage.

[hughesdt]

I thought that it was an electrical dampening that was different from the OP new gauge compared to the one in my VX. That is why I asked to see pictures of his and got his old gauge to try and modify it. But I couldn't see any difference in the 3 that I have looked at, 4 if you count the Rodeo in the scrap yard.

It does have an electrolytic capacitor in that circuit and I assume that it is there for dampening, but they are all the same.

[eternal21]

n/a

[tom4bren]

I thought that it was an electrical dampening that was different from the OP new gauge compared to the one in my VX. That is why I asked to see pictures of his and got his old gauge to try and modify it. But I couldn't see any difference in the 3 that I have looked at, 4 if you count the Rodeo in the scrap yard.

It does have an electrolytic capacitor in that circuit and I assume that it is there for dampening, but they are all the same.

It doesn't suprise me that the guages are all the same. I have no clue as to why our guages are having a problem with the dampening circuit & the others aren't. I'm pretty sure that either the electrolytic capacitor or a resistor are bad (either could be bad without showing any visible clues).

[Amnesia]

I'm curious about the comments about the clusters being the same from those who have "looked" at them... Are we talking a visual inspection and comparison or has anyone measured the ohms on the resistors to see if they're good or not.

I haven't had my cluster out, but it looks a lot simpler and less complex than I'd imagined. Seems like it'd be easy to test it and replace the offending resistor(s)...

Has anyone tried ohm'ing them out?

[eternal21]

n/a

[WyldWeasel]

Wow, my husband's Proton just started doing this yesterday. Good to know what the fix is and that there's a chance the Rodeo part may work. Keep us posted on actually replacing the resistor. If it does fix the issue, then I'll be telling the hubby to get his soldering iron ready. :)

[eternal21]

Trooper clusters won't work. The printed circuit board on the back of the fuel/temp portion of the cluster is different than that of the VX, and it has 5 posts in which to mount it in the cluster, whereas the VX has 4 posts.