C5 Fuel Gauge
Thread Starter
3rd Gear
Joined: Jul 2003
Posts: 3
Likes: 0
From: Santa Clarita CA
C5 Fuel Gauge
This past weekend, while visiting the central California coast wine country, my check gauges light came on, I recieved a low fuel indication and the fuel gauge indicated zero fuel even though I had 3/4 of a tank. When I filled the tank (needed only 1/4 tank to fill) the gauge again worked and showed full. Later in the day, I experienced the same faulty fuel gauge problem. Thereafter, it seemed to occur after the car had been driven for several miles. I must admit that, since I don't drive particularly hard (especially with my wife in the car) I've been using regular gas. I have seen some posts that indicate the fuel sending unit should be removed and cleaned while others mention the use of Techron as the solution. Does anyone have any ideas?
Le Mans Master
Joined: Nov 2001
Posts: 6,984
Likes: 0
From: Central Coast CA
Try the Techron solution first. I'd use Chevron gas all the time though because all grades of it have Techron in it. If this doesn't correct the problem you may have no choice but to take it in for warranty service.
Race Director
Joined: Jul 2005
Posts: 11,308
Likes: 1
From: The Beautiful Greater Bay Area California
Hello Dennis,
I agree with Shylor: Do try switching over to Chevron Premium. And, insert a bottle of the Techron II fuel system cleaner additive to your full tank of gas. It appears that the integrated C5 fuel pump assembly units are very sensitive to some of the sulphur deposits that may accumulate over time when using other brands and grades of gasoline. This build up on the fuel sensor will contribute to the erratic fuel gauge reading symptomology experienced by many C5 owners. The brand of gasoline that seems to be less conducive to this problematic issue is the Chevron gasoline. In my own experience, if I use Arco or Shell, I will get erratic fuel gauge readings. Eventually, I did have the passenger side fuel pump assembly replaced, and, the PC reflashed at the Dealership. However, when I started using the Shell or Arco (these are the fuel stations closest to me), the gauge would act up again. So, I have stayed with the Chevron ever since with no more erratic reading. Also, I now regularly add the Techron II fuel system cleaner at every tune up interval. Lastly, if you have over 30K, you may look into also changing your fuel filter. Good luck to you.
I agree with Shylor: Do try switching over to Chevron Premium. And, insert a bottle of the Techron II fuel system cleaner additive to your full tank of gas. It appears that the integrated C5 fuel pump assembly units are very sensitive to some of the sulphur deposits that may accumulate over time when using other brands and grades of gasoline. This build up on the fuel sensor will contribute to the erratic fuel gauge reading symptomology experienced by many C5 owners. The brand of gasoline that seems to be less conducive to this problematic issue is the Chevron gasoline. In my own experience, if I use Arco or Shell, I will get erratic fuel gauge readings. Eventually, I did have the passenger side fuel pump assembly replaced, and, the PC reflashed at the Dealership. However, when I started using the Shell or Arco (these are the fuel stations closest to me), the gauge would act up again. So, I have stayed with the Chevron ever since with no more erratic reading. Also, I now regularly add the Techron II fuel system cleaner at every tune up interval. Lastly, if you have over 30K, you may look into also changing your fuel filter. Good luck to you.
Race Director
Joined: Jul 2004
Posts: 16,795
Likes: 62
From: Lake Havasu City, AZ
Dennis,
This is a common problem with lots of prior posts.
There are two likely culprits....
Sulfur deposits on the fuel level sensing unit caused by use of gas with high sulfur levels ( or low detergent levels)
1. Several tanks of good quality fuel might help see www.toptierfuel.com
2. Quicker results are likely from using a fuel system cleaning additive like
Chevron techron or Chemtool B-12 ( Walmart carries both)
It might take two to three tankfulls using this method before you can tell if it worked (based on previous posts)
If that does not do it the next trick is to look for corrosion on the ground connection to the sending unit. I know that I've seen some posts with photos on where to find it.
Finally others report that they have had to replace the faulty sending unit. there are alos posts on how to do that.
I like to start with the simple and work to the more difficult/expensive
That why I listed the way I did.
This is a common problem with lots of prior posts.
There are two likely culprits....
Sulfur deposits on the fuel level sensing unit caused by use of gas with high sulfur levels ( or low detergent levels)
1. Several tanks of good quality fuel might help see www.toptierfuel.com
2. Quicker results are likely from using a fuel system cleaning additive like
Chevron techron or Chemtool B-12 ( Walmart carries both)
It might take two to three tankfulls using this method before you can tell if it worked (based on previous posts)
If that does not do it the next trick is to look for corrosion on the ground connection to the sending unit. I know that I've seen some posts with photos on where to find it.
Finally others report that they have had to replace the faulty sending unit. there are alos posts on how to do that.
I like to start with the simple and work to the more difficult/expensive
That why I listed the way I did.
7th Gear
Joined: Sep 2005
Posts: 7
Likes: 0
fAULTY FUEL GAUGE
I have a 2004 Convertible Corvette, 11,700 miles. Have only used Premium gas. The fuel tank had a leak, took it to dealership, they ordered a new fuel tank, once they got inside they said it had other problems, said it happened on the assembly line when built. Took 2 weeks to get all parts and replace. 2,000 miles later I filled the tank and drove about 50 miles, tank showed empty. Stopped and refueled. put about 2 gallons in. About 50 miles later it started working. Took to dealership, they say faulty parts and they are replacing. Anyone had problems similiar to this? My driver's window has been fixed twice, fuel related problems ongoing. Thanks.
Advanced
Joined: Feb 2005
Posts: 74
Likes: 1
fuel gauge
I’ve had some sticky gas gauge problems. I tried techron. It didn’t do anything for my problem. It seams to Work for a lot of people. I’m not sure why. If you think of all the cars around that don’t use Chevron gas that never have problems. Seems like only corvettes have problems. And they probably use the same float mechanism a lot of other GM cars do. I read a thread (see below) that goes into a lot of detail about grounds, particularly the grounds under the hood that have about ten wires grouped together in black boxes. I checked mine and found the right one corroded. I cleaned it and a lot of intermittent problems went away for a while. including gas gauge problems. But after a while they would come back. Finally I cut off the black box soldered all the wires to a copper strip and fastened it to the ground lug and every thing has worked well so far. I’m sure this isn’t the answer for everyone’s gas gauge problems but it worked for me. You might try this, if your gauge is reading improperly get in the car turn on the key and have someone wiggle the wires that go into the black box on the right side and see if anything changes. If it does you should clean the ground per the thread.
http://forums.corvetteforum.com/show...nds&forum_id=1
http://forums.corvetteforum.com/show...nds&forum_id=1
Racer
Joined: Nov 2004
Posts: 288
Likes: 0
Originally Posted by W Muller
I’ve had some sticky gas gauge problems. I tried techron. It didn’t do anything for my problem. It seams to Work for a lot of people. I’m not sure why. If you think of all the cars around that don’t use Chevron gas that never have problems. Seems like only corvettes have problems. And they probably use the same float mechanism a lot of other GM cars do. I read a thread (see below) that goes into a lot of detail about grounds, particularly the grounds under the hood that have about ten wires grouped together in black boxes. I checked mine and found the right one corroded. I cleaned it and a lot of intermittent problems went away for a while. including gas gauge problems. But after a while they would come back. Finally I cut off the black box soldered all the wires to a copper strip and fastened it to the ground lug and every thing has worked well so far. I’m sure this isn’t the answer for everyone’s gas gauge problems but it worked for me. You might try this, if your gauge is reading improperly get in the car turn on the key and have someone wiggle the wires that go into the black box on the right side and see if anything changes. If it does you should clean the ground per the thread.
http://forums.corvetteforum.com/show...nds&forum_id=1
http://forums.corvetteforum.com/show...nds&forum_id=1
I was having the same problem intermittently and when I started using Chevron (from the same station) it has gone away. Knock knock knock! (knocking on wood!
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Thread Starter
3rd Gear
Joined: Jul 2003
Posts: 3
Likes: 0
From: Santa Clarita CA
Thanks, my friend. I couldn't help notice that you live in East Lansing. I'm an MSU grad (old grad, BA-1966 & MBA-1967) and try to get to the campus about every other summer when I vacation in Michigan. I've lived in Southern California for 30 years but still miss my native Michigan - the summers that is but I don't miss the winters. Go Green. Best regards, Dennis
Racer
Joined: Nov 2004
Posts: 364
Likes: 2
From: Picton Ontario
You can also remove and clean the sending unit...
http://forums.corvetteforum.com/show....php?t=1117236
http://forums.corvetteforum.com/show....php?t=1117236
3rd Gear
Joined: Jun 2005
Posts: 3
Likes: 0
I, too, have experienced the fuel gauage problem. I have had both fuel sending units repleaced and all related hoses and valves. It did not help. I contacted Pat Goss (Goss's Garage on Auto World). He has a C5 and experienced the same problem. Stated that it could be caused by sulfer content in some gasolines. He recommended adding BG44K a fuel system additive. I found it on the internet, but it is pricey. Added it to the fuel tank while using Chevron with Techtron and I have not had a recurrence of the problem.
