Dumb Question, but....
Thread Starter
Melting Slicks
Joined: Mar 2009
Posts: 2,300
Likes: 115
From: Odessa FL
St. Jude Donor '10-'12-'13-'14-'15-'16-'17
Dumb Question, but....
...why do C5's (I am assuming that it is particular to C5's) have so much difficulty with the fuel gauge? I have run into it and treated it with Techron and now only use Exxon gas, but can't wonder why this is an issue. I know some of the issues with sulphur deposits, but why only with the vette? I guess I am asking what is the fundamental engineering problem that needs to be fixed, the sending unit, the gauge,...?
I haved owned and currently own a vast array of other cars and none seem to have had this issue. I always took the fuel gauge operating correctly as a given in todays automotive environment and I am perlexed that the vette would have this type of an issue.
I haved owned and currently own a vast array of other cars and none seem to have had this issue. I always took the fuel gauge operating correctly as a given in todays automotive environment and I am perlexed that the vette would have this type of an issue.
Last edited by alxltd1; Nov 21, 2009 at 03:15 PM.
Team Owner
Joined: Jul 2006
Posts: 22,164
Likes: 4,172
From: Kannapolis NC
It happens a lot, but nearly as much as it sounds like when you read the forum. Remember, for every one you read about, there are thousands that don't have a problem. I've had two and have never seen the fuel gauge or oil pressure sensor, or the rear end leak. I don't think I'm lucky, I think the majority don't have the problem.
Thread Starter
Melting Slicks
Joined: Mar 2009
Posts: 2,300
Likes: 115
From: Odessa FL
St. Jude Donor '10-'12-'13-'14-'15-'16-'17
It happens a lot, but nearly as much as it sounds like when you read the forum. Remember, for every one you read about, there are thousands that don't have a problem. I've had two and have never seen the fuel gauge or oil pressure sensor, or the rear end leak. I don't think I'm lucky, I think the majority don't have the problem.
Team Owner
Joined: Jul 2006
Posts: 22,164
Likes: 4,172
From: Kannapolis NC
The problem is that the sending unit is inside the tank and in the fuel. I think that's a bad idea, but it's the way it is. The only fix for sure is to replace the sending unit. I don't know of any improved unit available, but if someone has one, I think they can make good money. The Techron helps clean of the deposits on the rheostat part of the sending unit so that it makes better contact to read the position of the sensor. Personally, I think keeping the tank full all the time increases the likelihood of seeing the problem. Running down to a lower amount and refilling forces the movement of the sensor and therefore helps keep it from becoming coated. I can't prove it, so take it for what it is.
Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
The problem is that the sending unit is inside the tank and in the fuel. I think that's a bad idea, but it's the way it is. The only fix for sure is to replace the sending unit. I don't know of any improved unit available, but if someone has one, I think they can make good money. The Techron helps clean of the deposits on the rheostat part of the sending unit so that it makes better contact to read the position of the sensor. Personally, I think keeping the tank full all the time increases the likelihood of seeing the problem. Running down to a lower amount and refilling forces the movement of the sensor and therefore helps keep it from becoming coated. I can't prove it, so take it for what it is.
Safety Car
Joined: Apr 2003
Posts: 3,732
Likes: 21
From: Napa Ca
I always thought it was the other way around. You should keep the gas tank full at all times to keep everything submerged. Aren't deposits formed when a liquid is allowed to evaporate and thus leaving behind contaminants and undiluted chemicals? I may be wrong but I was always under this assumption. It does make sense though.
I seem to get the problem if I let the vette sit too long with a near empty tank.
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Racer
Joined: Dec 2007
Posts: 413
Likes: 1
From: Simi Valley CA
I've owned two C5's. Both have had the gas gauge problem. I only use Chevron fuel. But, of course don't know what the previous owners used. Both cars had less than 18k miles on them at the time of the problem. I remember cruising on the freeway in my Jeep, when a C5 passed by. I looked over and noticed his dash also had the red low fuel warning light on. Maybe he was just running low on gas, maybe not. I'm guessing for those that haven't had that problem . . . it's only a matter of time. I'm in California and my brother lives in Oregan. His low mileage 03 Z06 also had the gas gauge problem. Hmmmm! I've owned alot of cars and trucks over the 45 years that I've been driving. My two C5's where the only cars that had a gas gauge problem.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
I always thought it was the other way around. You should keep the gas tank full at all times to keep everything submerged. Aren't deposits formed when a liquid is allowed to evaporate and thus leaving behind contaminants and undiluted chemicals? I may be wrong but I was always under this assumption. It does make sense though.
I had my first problem 4 years ago in Vegas. I used Techron and it was fine until a few months ago. I had one glitch when I ran the tank very low to get to a gas station that sold 98 octane. the most recent example, I still had nearly 1/2 a tank. No consistency. I found on both occasions recently that if I top the tank off it starts working again. As a precaution I've added Techron each time. I've also switched to Shell V Power gas.
If it becomes a regular problem I'll have to bite the bullet and change the sender.
Here's a pic of the sender that RJ1AZ kindly posted. You can see the offending pick offs that get corroded or contaminated.
His post is worth a read
http://forums.corvetteforum.com/show....php?t=2027250
Last edited by DeeGee; Nov 21, 2009 at 02:37 AM.
Thread Starter
Melting Slicks
Joined: Mar 2009
Posts: 2,300
Likes: 115
From: Odessa FL
St. Jude Donor '10-'12-'13-'14-'15-'16-'17
So it seems that the consensus opinion is that it is the sending unit that causes the problem, though there is still debate as to why.
However, just replacing the sending unit with another from GM would seem to mean that it will only again go bad over time. But without an aftermarket alternative, or unless the new units from GM are improved, there is no other option. I would wonder if anyone has ever converted another make sending unit or even an alternative set up, say outside the tank?
Oh well until there is another option I will continue to run Techron through it on occassion. Thanks for all the info.
However, just replacing the sending unit with another from GM would seem to mean that it will only again go bad over time. But without an aftermarket alternative, or unless the new units from GM are improved, there is no other option. I would wonder if anyone has ever converted another make sending unit or even an alternative set up, say outside the tank?
Oh well until there is another option I will continue to run Techron through it on occassion. Thanks for all the info.
Melting Slicks
Joined: Nov 2008
Posts: 3,146
Likes: 203
From: Edmonton Alberta, Canada
I recall some years ago Shell lost a class action lawsuit with Chrysler/Dodge owners over just such issues, gummed up fuel sending units. So you see, it is not the fuel sending units that are the problem...but the fuel. Hence, certian gas suppliers seem to fix the problem. Others are the problem. Stay away from suspect suppliers eg. Shell gas. Rob
Safety Car
Joined: Apr 2004
Posts: 3,996
Likes: 77
From: Louisville KY
It happens a lot, but nearly as much as it sounds like when you read the forum. Remember, for every one you read about, there are thousands that don't have a problem. I've had two and have never seen the fuel gauge or oil pressure sensor, or the rear end leak. I don't think I'm lucky, I think the majority don't have the problem.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
I think were drifting into symptom vs cause here
The sulfur in the gas clogs up the sender
Either way Techron usually fixes it.
The sulfur in the gas clogs up the sender
Either way Techron usually fixes it.
Le Mans Master
Joined: Sep 2007
Posts: 7,604
Likes: 8
From: Belleville Il
IMO Techron IS treating the root problem.I drive mine all the time,thus the float is always moving,,I only run top tier gas(including Shell 93 octane V power) and a few times a year add extra Techron. So far not even a HINT of a problem(Knock on wood
)!!I agree that just from reading many post on this a very common factor seems to be cars that are not driven,,,SITTING with less than full tanks, MAY very well be a contributing factor. Not often are these problems reported on cars that are on the move on a very frequent basis. Just an observation,,not a researched fact though!! Add Techron,,,and drive on!!
Last edited by itzza427; Nov 23, 2009 at 10:03 AM.