Gas Guge Question: Needle Bouncy; Bad Ground? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 09-29-2003, 05:26 AM

I think my Gas Gauge problem may lye in a bad ground connection. Tonight, I was driving around on a PERFECTLY smooth road, yet the needle was still bouncing. Also, when I was stopped at a red light, it was still bouncing. So, what wire should I check for continuity or what?
IIRC, the guage used in our trucks has only one wire going to the tank, and it's a ground wire, because the sensor in the tank is basically a resistor, when the tank is full, it reads 0ohm, when the tank is empty it reads 90ohm, right?

loweredd · 09-29-2003, 02:46 PM

I was wondering the same thing. Mine goes all over the place. I never know how much gas I hav for sure. It doesnt really bounce, just goes all over the dial.

79Chevypickup · 09-29-2003, 03:51 PM

Mine does the same thing...
I just look at what I think is about the middle of
the bouncing and assume thats how much gas I
have.
I accutally started to think it was normal...
Is it?

Prerunner1982 · 09-29-2003, 05:38 PM

depends on what you mean by bouncy? every old chevy truck i have seen the needle will move when you accelerate or brake, But if it bounces on a straight smooth road at a constant speed then it may be a wiring or sending unit problem. The connection the float makes with the unit, not sure what it is called the part that controls the ohm that is sent to the guage.. you know what i am talking about?

79Chevypickup · 09-29-2003, 05:49 PM

So what you are saying is, is that it could be the sending unit for the gas gauge (the one on top of the gas tank)
or
It could also be bad wiring
or
A combination of the both

This is what you are saying right?

79BIG10 · 09-29-2003, 05:59 PM

First check your ground. Then if that's good it's your float inside the tank. It's probably moving alot and thus giving the bouncy reading to the gauge itself.

Prerunner1982 · 09-29-2003, 06:47 PM

mine "bounces" but only under acceleration and braking. As far as i know from what has been discussed on here that is fairly normal.

*1FaastC10* · 09-29-2003, 08:25 PM

of the 30+ GM trucks ('49-'97)i have had experience with (most of which belonged to family/friends) ALL had a "bouncy" gas guage. the only exceptions i've found are the 99+ trucks. if my assumptions are correct, they have a baffled fuel tank.

loweredd · 09-29-2003, 08:39 PM

oh yeah, that could be the case. Probably just replacing the sending unit isn't going to do it.

We'll see when I put in a foamed fuel cell.

09-29-2003, 05:26 AM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Gas Guge Question: Needle Bouncy; Bad Ground? I think my Gas Gauge problem may lye in a bad ground connection. Tonight, I was driving around on a PERFECTLY smooth road, yet the needle was still bouncing. Also, when I was stopped at a red light, it was still bouncing. So, what wire should I check for continuity or what? IIRC, the guage used in our trucks has only one wire going to the tank, and it's a ground wire, because the sensor in the tank is basically a resistor, when the tank is full, it reads 0ohm, when the tank is empty it reads 90ohm, right? __________________ I have a few cars... See Them Here

09-29-2003, 03:51 PM	#3
79Chevypickup MY TRUCK IS FOR SALE!! Join Date: Sep 2003 Location: Pasadena, TX Posts: 292	Me Too Me Too!! Mine does the same thing... I just look at what I think is about the middle of the bouncing and assume thats how much gas I have. I accutally started to think it was normal... Is it? __________________ 1979 Chevy LWB 350ci / 700R4 Edelbrock under the hood F O R S A L E OR T R A D E

09-29-2003, 05:38 PM	#4
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,906	depends on what you mean by bouncy? every old chevy truck i have seen the needle will move when you accelerate or brake, But if it bounces on a straight smooth road at a constant speed then it may be a wiring or sending unit problem. The connection the float makes with the unit, not sure what it is called the part that controls the ohm that is sent to the guage.. you know what i am talking about? __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

09-29-2003, 05:49 PM	#5
79Chevypickup MY TRUCK IS FOR SALE!! Join Date: Sep 2003 Location: Pasadena, TX Posts: 292	So what you are saying is, is that it could be the sending unit for the gas gauge (the one on top of the gas tank) or It could also be bad wiring or A combination of the both This is what you are saying right? __________________ 1979 Chevy LWB 350ci / 700R4 Edelbrock under the hood F O R S A L E OR T R A D E

09-29-2003, 05:59 PM	#6
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	First check your ground. Then if that's good it's your float inside the tank. It's probably moving alot and thus giving the bouncy reading to the gauge itself. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

09-29-2003, 02:46 PM	#2
loweredd www.loweredd.com Join Date: Aug 2002 Location: Struble IA Posts: 808	I was wondering the same thing. Mine goes all over the place. I never know how much gas I hav for sure. It doesnt really bounce, just goes all over the dial.

09-29-2003, 06:47 PM	#7
Prerunner1982 Registered User Join Date: Oct 2002 Location: Edmond, OK Posts: 5,906	mine "bounces" but only under acceleration and braking. As far as i know from what has been discussed on here that is fairly normal. __________________ Jon 1982 Chevy Silverado 350/th350.... RETIRED 1993 Jeep XJ 2 door(Cherokee) 4wd 4.0ltr/AX-15 (5spd)/NP231 .... Oklahoma Roll Call

09-29-2003, 08:25 PM	#8
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,400	of the 30+ GM trucks ('49-'97)i have had experience with (most of which belonged to family/friends) ALL had a "bouncy" gas guage. the only exceptions i've found are the 99+ trucks. if my assumptions are correct, they have a baffled fuel tank.

09-29-2003, 08:39 PM	#9
loweredd www.loweredd.com Join Date: Aug 2002 Location: Struble IA Posts: 808	oh yeah, that could be the case. Probably just replacing the sending unit isn't going to do it. We'll see when I put in a foamed fuel cell.

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