Gas Guage.

My gauge also drops like a rock after the 1/2 mark is reached. If I let it go to the actual E line, it takes about 16gal to fill. I don't like to go below 1/4 though.

On my '95 it does seem to stay on the top half a good bit longer, then drops a little quicker on the bottom half. On the '99 they must or might have corrected something because it seems to go from full to half to as low as I let it get more evenly.

1998 Riv wrote:

My gauge also drops like a rock after the 1/2 mark is reached. If I let it go to the actual E line, it takes about 16gal to fill. I don't like to go below 1/4 though.

my 98 experiences about the same...

This was a complaint on the Riviera and the Aurora. I'd read a few years ago about Aurora complaints where the needle stays on full forever, then drops like a stone...

My Riv isn't quite that bad, but it does go down quicker once it's past 3/4's

Staying at full after filling up is normal with most cars. Once the level is above the sensor's limit, what is it supposed to do?

Mine doesn't bother me. Only thing I notice is the level goes down faster below about 1/3 tank. I have 30-50 miles after the light comes on, and the needle is reading well below "E" at that point. It's always consistent though. To run out of gas in this car is near impossible.

95 Riviera SC... My gas guage does not work for some reason. It jumps from empty to full alot and I was wondering if there is any simple explanation for this...

Thanks.
RivRuss.

The simple explanation would be a short in the wiring. Did you touch any of the stock wiring when installing the system. Drill any holes?

I didnt do the wiring.... Someone else did.. Im sure thats where the problem lies. I was just hoping it wasnt....

RiviRuss wrote:

I didnt do the wiring.... Someone else did.. Im sure thats where the problem lies. I was just hoping it wasnt....

lol, what? you dont trust your installer?

RiviRuss wrote:

I didnt do the wiring.... Someone else did.. Im sure thats where the problem lies. I was just hoping it wasnt....

It may not be. Many Rivs have fuel guages that do not read correctly. My system is stock and the fuel guage acts crazy. What I have heard in the past is that there are parts on the sending unit that corrode, and the only solution is to replace the sending unit (big $?).

The sending unit is stll extremely basic. Just a float that moves a contact over a resistive wire, similar to the dimmer for your interior lights. It's a design that hasn't really been improved on since the 50's. Every GM I have owned has eventually lost the gas gauge.

Just for kicks, my dad has a '54 MGTF. It has an aftermarket dipstick in the tank that tells how many gallons are in there. You check it before you drive. If the gas level gets really low a big amber light glows on the dash (factory). No gauge.

My '86 suburban's gas gauge gave up the ghost while I was offroading one day. Just tripped over to F and never came back. I just put gas in it every 250 miles and I knew I'd be safe. (it had a 45 gallon tank).

deekster_caddy wrote:

My '86 suburban's gas gauge gave up the ghost while I was offroading one day. Just tripped over to F and never came back. I just put gas in it every 250 miles and I knew I'd be safe. (it had a 45 gallon tank).

I had an 89 F150 with dual tanks. Both sending units died during the 4-5 years I owned it. Filled at 150 miles in winter, 200 in summer. Switched between tanks from time to time to keep the gas fresh, but always kept one full. Dealer wanted $350 per tank to replace the pump/sending unit combo. I said no thanks, and had no desire to do it myself, would have to drop the tanks.

quote: "Many Rivs have fuel guages that do not read correctly. My system is stock and the fuel guage acts crazy. "

Does this include jumping from fuel to empty, like RivRuss is experiencing?

oh yeah, that does sound more like a break in the wire, or it's rubbing against a ground somewhere.

I forget - if you ground the sending unit wire does that put the gauge to full or empty?

AA wrote:

quote: "Many Rivs have fuel guages that do not read correctly. My system is stock and the fuel guage acts crazy. "

Does this include jumping from fuel to empty, like RivRuss is experiencing?

From half to full anyway. I don't let it get lower than that for fear of running out.

It may be a ground problem as you say, and probably is if it showed up right after his stereo install.

mine seems to work normally from a full tank to about half, then it kind of just sits and sometimes goes to full. It's consistent with this behavior so I'm pretty sure its the resistor for the float. I'm not spending all kinds of money and pulling the tank and pump to fix that. Thank you trip meter

turtleman wrote:

mine seems to work normally from a full tank to about half, then it kind of just sits and sometimes goes to full. It's consistent with this behavior so I'm pretty sure its the resistor for the float. I'm not spending all kinds of money and pulling the tank and pump to fix that. Thank you trip meter

mine has always gone from full to half slowly, and from half to empty fast.

now it still does that, just more dramatically. And sitting on an incline affects the gauge alot more too. I can get and extra 1/8 tank at least sitting on a 30degree incline.

now if it were only accurate. I think I will just check/clean my connections whenever I have to replace the fuel pump.

There is a fix for this (staying past F for a long time then dropping like a rock). I posted about it a while back. It is common to many GM cars. They all have basically the same wiring for the fuel gauge.

by adding a small resistance you can calibrate what is the "full" mark on your car. It usually evens out the bottom half too.

That's a very good idea, Jason. Has anyone done this? By using a potentiometer, you could fine tune a full tank of gas to register as "F".

Jason, that's a great solution. Any chance you have a link to it? I thought of the same solution a few years ago but never did anything about it

I can show you exactly what I mean, but not on a riviera.
fuel gauge calibrator for the b-body.
There are even detailed istructions on how to install it. You could just buy his, it's only 10$ Install is exactly the same, it's the same 0-90 ohm system.

having the gauge jumping up and down can have to do with the sending unit but you do not have to replace the whole unit. there is a sensor that goes with the float the sensor is ontop of the sending unit outside it is a/b 1"x2" with a pulg in. they are expencive but cheeper then a new sending unit.