Gas Gauge failure
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Army
What DTC do you get when it trips? My buddy increased the potentiometer arm tension some and eliminated his issues.
Have you examined the connectors for bad female pin connections? GM has VERY poor female pins. They have a tung that looses tension and makes a poor intermittent contact. Ive had that same urge to burn the bitch but, figured where all my issues were stemming from.
Obtain and old male pin the same size and shape as the circuit male pin. Heres the one that I use for most all the pins i test:
Just insert the pin into a female pin. There should be a nice tight fit on each female pin.
Bill
What DTC do you get when it trips? My buddy increased the potentiometer arm tension some and eliminated his issues.
Have you examined the connectors for bad female pin connections? GM has VERY poor female pins. They have a tung that looses tension and makes a poor intermittent contact. Ive had that same urge to burn the bitch but, figured where all my issues were stemming from.
Obtain and old male pin the same size and shape as the circuit male pin. Heres the one that I use for most all the pins i test:
Just insert the pin into a female pin. There should be a nice tight fit on each female pin.
Bill
Drifting
Joined: Feb 2005
Posts: 1,770
Likes: 0
From: in ur mirror, 'bout to pass.. CA
Hi Bill, thanks for responding. I came to this post late; I took the car to Hargreave Chevy on the recommendation of my service manager at Mike Savoi Chevy (bought the Camaro there). He said they have a Corvette-only mechanic, Tom, that's one of the best in the business. Dropped if off this morning, and Tom asked some very good questions, listened to what I had done so far, and said he could fix it (of course he's going to say that!). Labor rate hurt though; $95 an hour!
So I've caved and decided to let a pro handle the job. I can keep throwing money at it, but in the long run that's not a good idea. Pay someone with waay more knowledge of these cars than me to fix it right. Right?
So I've caved and decided to let a pro handle the job. I can keep throwing money at it, but in the long run that's not a good idea. Pay someone with waay more knowledge of these cars than me to fix it right. Right?
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
Army,
C5s aren't the only cars affected by the sulpher in the gas. Every make has the problem. I just ran across a Honda TSB for the same issue. Several years ago a refinery in the Northwest section of PA ran a really bad batch of gas that ruined hundreds of gas gauges pretty much all at the same time. The PA Attorney General forced them to pay for the damages they caused.
Bill
C5s aren't the only cars affected by the sulpher in the gas. Every make has the problem. I just ran across a Honda TSB for the same issue. Several years ago a refinery in the Northwest section of PA ran a really bad batch of gas that ruined hundreds of gas gauges pretty much all at the same time. The PA Attorney General forced them to pay for the damages they caused.
Bill
Drifting
Joined: Feb 2005
Posts: 1,770
Likes: 0
From: in ur mirror, 'bout to pass.. CA
Oh, I know, but we are a rather narrow audience of fools, so the instances of faulty gauges amonsgt the years seems abnormally high.
SO; just got home from picking up the car from it's second day of diagnosing. Still busted. Tom Adams (the corvette mechanic exclusively) tells me he cannot find anything mechanically wrong with the system; both sensors are working as they should, according the the Tech II scan. He spoke with someone else familiar with the C5 models, a retired designer/engineer, who recommended pulling the entire system out and conducting a detailed inspection of all hoses, lines, connections, tanks and pumps. Then clean everything up and put it back together. Tom thinks there might be an obstruction within the lines to and from the senders, causing one tank to fill/empty at a different rate than the other. This imbalance in levels makes the computer fail to compensate, thus my erratic gauge. He wants $1000 to do it at the shop. I'm for doing it in my garage, if at all.
Army
SO; just got home from picking up the car from it's second day of diagnosing. Still busted. Tom Adams (the corvette mechanic exclusively) tells me he cannot find anything mechanically wrong with the system; both sensors are working as they should, according the the Tech II scan. He spoke with someone else familiar with the C5 models, a retired designer/engineer, who recommended pulling the entire system out and conducting a detailed inspection of all hoses, lines, connections, tanks and pumps. Then clean everything up and put it back together. Tom thinks there might be an obstruction within the lines to and from the senders, causing one tank to fill/empty at a different rate than the other. This imbalance in levels makes the computer fail to compensate, thus my erratic gauge. He wants $1000 to do it at the shop. I'm for doing it in my garage, if at all.
Army
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Oh, I know, but we are a rather narrow audience of fools, so the instances of faulty gauges amonsgt the years seems abnormally high.
SO; just got home from picking up the car from it's second day of diagnosing. Still busted. Tom Adams (the corvette mechanic exclusively) tells me he cannot find anything mechanically wrong with the system; both sensors are working as they should, according the the Tech II scan. He spoke with someone else familiar with the C5 models, a retired designer/engineer, who recommended pulling the entire system out and conducting a detailed inspection of all hoses, lines, connections, tanks and pumps. Then clean everything up and put it back together. Tom thinks there might be an obstruction within the lines to and from the senders, causing one tank to fill/empty at a different rate than the other. This imbalance in levels makes the computer fail to compensate, thus my erratic gauge. He wants $1000 to do it at the shop. I'm for doing it in my garage, if at all.
Army
SO; just got home from picking up the car from it's second day of diagnosing. Still busted. Tom Adams (the corvette mechanic exclusively) tells me he cannot find anything mechanically wrong with the system; both sensors are working as they should, according the the Tech II scan. He spoke with someone else familiar with the C5 models, a retired designer/engineer, who recommended pulling the entire system out and conducting a detailed inspection of all hoses, lines, connections, tanks and pumps. Then clean everything up and put it back together. Tom thinks there might be an obstruction within the lines to and from the senders, causing one tank to fill/empty at a different rate than the other. This imbalance in levels makes the computer fail to compensate, thus my erratic gauge. He wants $1000 to do it at the shop. I'm for doing it in my garage, if at all.
Army
The fuel level in EITHER tank has nothing to do with the sensor DTCs. The sensors just tell the PCM what is in each tank and the PCM gives the IPC the info to display fuel level. If a sensor fails to provide the PCM fuel tank level data, it will error out and cause a DTC. It can error out because of a poor electrical connection, dirty Sensor, or both.
SO,,,,ripping all the fuel pluming out and cleaning it, will most likely not (in its self) solve the issue. However,,,removing and inspecting, cleaning , repairing all the ELECTRICAL CONNECTIONS in that circuit, can resolve the issue.
Hope this helps and saves you some cash!
Bill
Drifting
Joined: Feb 2005
Posts: 1,770
Likes: 0
From: in ur mirror, 'bout to pass.. CA
The fuel level in EITHER tank has nothing to do with the sensor DTCs. The sensors just tell the PCM what is in each tank and the PCM gives the IPC the info to display fuel level. If a sensor fails to provide the PCM fuel tank level data, it will error out and cause a DTC. It can error out because of a poor electrical connection, dirty Sensor, or both.
SO,,,,ripping all the fuel pluming out and cleaning it, will most likely not (in its self) solve the issue. However,,,removing and inspecting, cleaning , repairing all the ELECTRICAL CONNECTIONS in that circuit, can resolve the issue.
Hope this helps and saves you some cash!
Bill
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Heres the fuel pump/gage schematic. The switch MUST be in the ON or START position to run the pump.
Check the VOLTAGE on the fuel pump fuse. The C5 ignition switches are failing left and right lately. Make SURE that you have full battery voltage on the fuse. If not, the ignition switch contacts are burnt and maybe have some relationship to your issues.
Bill
Check the VOLTAGE on the fuel pump fuse. The C5 ignition switches are failing left and right lately. Make SURE that you have full battery voltage on the fuse. If not, the ignition switch contacts are burnt and maybe have some relationship to your issues.
Bill
Melting Slicks
Joined: Aug 2000
Posts: 2,618
Likes: 5
From: Overland Park KS
I had my gauge drop to empty over 40 times over a period of probably 6 months. If you get good at clearing your DIC codes you can have a working gauge in about 15 seconds. Seems the error code must trigger a "go to empty" state with the gauge and once the code is cleared the gauge returns to normal operation. Clearing the codes worked for me every time.
I used Techron and that fixed it for the most part but I wasn't happy having to use a bottle of Techron with about every other fill up.
I went on a mission to use a specific gas until either the problem went away or the gauge dropped to empty again. Fuel is different all over the country so I can't say what works/doesn't work will be the same for you. I tried the major and local brands and each one I got the fuel gauge dropping to empty. Eventually I tried Shell V-Power and for the last 15k miles I haven't had one issue with my gauge and haven't had to add techron. We don't have Chevron stations in this area, I believe Techron is an additive in Chevron gas.
I never did replace a pump or sending unit and now my '02 has 59k miles...
I used Techron and that fixed it for the most part but I wasn't happy having to use a bottle of Techron with about every other fill up.
I went on a mission to use a specific gas until either the problem went away or the gauge dropped to empty again. Fuel is different all over the country so I can't say what works/doesn't work will be the same for you. I tried the major and local brands and each one I got the fuel gauge dropping to empty. Eventually I tried Shell V-Power and for the last 15k miles I haven't had one issue with my gauge and haven't had to add techron. We don't have Chevron stations in this area, I believe Techron is an additive in Chevron gas.
I never did replace a pump or sending unit and now my '02 has 59k miles...
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Instructor
Joined: Dec 2005
Posts: 147
Likes: 3
From: Howell NJ
I have over 200,000 miles on my 2000, and this problem has ocured numerous times. Adding Tekron has fixed it every time. The car still has the original sending unit in it. It may take a couple of bottles but a bit of patience is a lot cheaper then a new sending unit every 30,000 miles.
I have a friend that is a mercades tech and he told me they have the same problem, so it is not unique to corvettes.
I have a friend that is a mercades tech and he told me they have the same problem, so it is not unique to corvettes.
Drifting
Joined: Feb 2005
Posts: 1,770
Likes: 0
From: in ur mirror, 'bout to pass.. CA
Maybe I got some magic working here...
Still on my first 20oz bottle of Techron. Picked up the car on Thursday from the dealer, drove home. Needle stayed at 1/4 full BUT DID NOT DROP to empty like all the other times. Drove the car on Friday too. Again, the gauge stayed in place, as if it were reading the correct fuel levels. Did drop some 'cuz I'm not light footed. Ima gonna fill up with Shell tomorrow and drop another 20oz bottle of Techron in the tank. We'll see...
Haven't pulled the fuel tanks yet; just pulled the sensor connections and cleaned them out as instructed!
Still on my first 20oz bottle of Techron. Picked up the car on Thursday from the dealer, drove home. Needle stayed at 1/4 full BUT DID NOT DROP to empty like all the other times. Drove the car on Friday too. Again, the gauge stayed in place, as if it were reading the correct fuel levels. Did drop some 'cuz I'm not light footed. Ima gonna fill up with Shell tomorrow and drop another 20oz bottle of Techron in the tank. We'll see...
Haven't pulled the fuel tanks yet; just pulled the sensor connections and cleaned them out as instructed!
Heel & Toe
Joined: Jan 2010
Posts: 16
Likes: 0
Wow...good to know I'm not the only one with this problem! I actually thought mine was heat-related. Only seems to happen to me on long trips. I drove from Salt Lake City down to Las Vegas. About 90 minutes into the trip (starting with a 3/4 tank of gas), the level suddenly dropped from a little above 1/2 tank to E. Scared the heck out of me when that light came on. I limped to the nearest gas station, and put in about 8 gallons of gas. Strange. Pulled the owner's manual just to be sure I didn't drive into the Twilight Zone...
So, I had the passenger side unit replaced. Drove it home, no trouble. Drove it back and forth to work, 30 minutes each. No problem. Moved to Houston last week and drove it here. About two or three hours into the trip, it dropped to E again. At first it was only doing it when I got down to about 1/2 tank. I went to Baton Rouge last week, and it started dropping from higher levels, even from 3/4. BUT...after it cools off...say a day later, and I start it, half the time it works fine.
Gonna go pick up two bottles of Techron and begin the treatments!!!
So, I had the passenger side unit replaced. Drove it home, no trouble. Drove it back and forth to work, 30 minutes each. No problem. Moved to Houston last week and drove it here. About two or three hours into the trip, it dropped to E again. At first it was only doing it when I got down to about 1/2 tank. I went to Baton Rouge last week, and it started dropping from higher levels, even from 3/4. BUT...after it cools off...say a day later, and I start it, half the time it works fine.
Gonna go pick up two bottles of Techron and begin the treatments!!!
Racer
Joined: Nov 2009
Posts: 488
Likes: 0
From: Corpus Christi Texas
Hey guys, sorry to hijack but I had a question. So the corvette has TWO fuel tanks correct? Does it siphon fuel out of one into the other when it goes into "Reserve Fuel" mode? I'm a little confused reading all this stuff about LHS and RHS tanks.
Le Mans Master
Joined: Sep 2006
Posts: 5,256
Likes: 1
From: Charlotte NC
St. Jude Donor '08-'09-'10-'11
Wow...good to know I'm not the only one with this problem! I actually thought mine was heat-related. Only seems to happen to me on long trips. I drove from Salt Lake City down to Las Vegas. About 90 minutes into the trip (starting with a 3/4 tank of gas), the level suddenly dropped from a little above 1/2 tank to E. Scared the heck out of me when that light came on. I limped to the nearest gas station, and put in about 8 gallons of gas. Strange. Pulled the owner's manual just to be sure I didn't drive into the Twilight Zone...
So, I had the passenger side unit replaced. Drove it home, no trouble. Drove it back and forth to work, 30 minutes each. No problem. Moved to Houston last week and drove it here. About two or three hours into the trip, it dropped to E again. At first it was only doing it when I got down to about 1/2 tank. I went to Baton Rouge last week, and it started dropping from higher levels, even from 3/4. BUT...after it cools off...say a day later, and I start it, half the time it works fine.
Gonna go pick up two bottles of Techron and begin the treatments!!!
So, I had the passenger side unit replaced. Drove it home, no trouble. Drove it back and forth to work, 30 minutes each. No problem. Moved to Houston last week and drove it here. About two or three hours into the trip, it dropped to E again. At first it was only doing it when I got down to about 1/2 tank. I went to Baton Rouge last week, and it started dropping from higher levels, even from 3/4. BUT...after it cools off...say a day later, and I start it, half the time it works fine.
Gonna go pick up two bottles of Techron and begin the treatments!!!
I never had the problem until I drove from NC to MO a few weeks ago. Seemed like if I hit a big bump when it wasn't working it could come back for a bit. Also on the return trip I didn't have a passenger and it happed not nearly as much. Not worth fixing imo since it only occurred on long trips, but I did have to stop more than normal so I wouldnt risk running out of gas. Ill give the techron a try next time Im planning a big trip though since it doesnt happen around town.
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Race Director
Joined: Mar 2006
Posts: 15,449
Likes: 1,716
From: Everywhere and Nowhere at all
I am with Bill... check all of the connections, grounds on the car. Inexpensive and a god thing to do anyway. unplug the harness's in both doors, clean, re-attatch. BEST advice BILL ever gavem me.. 
Patience grasshoppa... these are far nice than the Porsche if you mod them right.
GL...
Patience grasshoppa... these are far nice than the Porsche if you mod them right.
GL...
