On the way home from getting the Vette from the car lot I discovered that the gas gauge never moved. It appeared to be stuck at full so I figured that it was the fule sending unit. Not a major issue I can changed that later. I filled it up and according to the display I can get over 300 miles from a fill up. I have been doing a bunch of city driving so the MPG is showing 17.9 right now (a little heavy in the foot at times... ) So, yesterday evening we roll the car over 200 miles on the trip meter and the gas gauge drops to 3/4 of a tank. The expected miles display drops to 222 miles and I am sitting with 212 on the trip meter when I see it.

I drive to the gas station and put in 13.5 gal. So, here is my question... Do I have just a 14 Gal tank? I was expecting a bigger tank more like around a 20 or so.

And, has anyone changed out the fuel sending unit recently? Is it part of the fuel pump assembly where I have to change EVERYTHING out?

Rocket Sapp

P.S. Yeah... I am getting the serivce manual right after the new year. I have to get Christmas for the boys you know....

 

I'm not sure, but if Corvettes are like most newer cars the fuel guage and fuel pump are all together. It's easier to change the whole assembly, than it is to swap out the defective sending unit.

 

Yeah it's easer... But will probably more than triple the cost involved. At least according to the Haynes book that I have for the car I would not have to drop the tank.


Tim

 

My 92 has a 20 gallon tank.
When my gauge reads 1/2 I start thinking about gas... when it hits 1/4 I need gas because I usually have 20-30 city miles till it reads "reserve".
I hate my gas gauge... the last 1/2 tank goes real fast.

 

It's a 20 gal tank.

 

All you have to do is remove the gas door/flap unit & there it is, the top of the tank.

 

Yeah, it would cost more, that's for sure, but is a lot easier. I've always changed the whole unit, as most have been in there several years, and the fuel pumps do weaken over time, and can cause problems. It's your call.

 

On my 93 I set the trip gauge with each fill up and then when I want to know how much gas I have left I look at the avg milage gauge and divide it into the number of miles I have on the tank. That tells me approximately how many gallons I have used and I deduct that from the tank capacity of 20 gallons. The other way to do it is to divide the number of miles it says you can drive by the avg. Miles per gallon and that will tell you approximately what you have left. Either way is a whole lot cheaper then trying to fix something that appears to be a common trait of this cars fuel gauge readout.

 

My 86 is exactly the same way.

 

I recently had the same problem with the sending unit on my '91 coupe.

While at MAM"s funfest this past September, I asked Gordon Kilebrew for his opinion on troubleshooting the system. He explained that the sending unit has a variable resistor which should have a resistance of 0 ohm's when the tank is empty and should increase to 90 ohms when the tank is full. He also explained a way to confirm or eliminate the sending unit as the cause of the problem. He suggested that I should remove the gas cap and the related parts below it. This allows access to the wiring connector for the fuel sending unit/fuel pump assembly. The next step is to disconnect the connector. Terminal A on the connector is a ground and terminal B is for the fuel sending unit. Gordon suggested that I should place a 90 ohm resistor across A and B. The fuel gage should read full. Next place a 45 ohm resistor across A and B. The gage should read 1/2 full. Next place a short piece of wire across A and B (effectively a 0 ohm resistor). The gage should read empty. If all of these check OK, then the problem is likely in the sending unit. Terminals A and B on the sending unit side of the connector can be checked with an ohm meter. If you happen to know exactly how much fuel is in the tank, then you can predict how much resistance it should have.

After returning home, I performed these checks and decided that my sending unit was at fault.

I nearly had a heart attack when I priced a new sending unit!

Being the independent-think I can fix anything-sort of person, I decided to take the sending unit out and investigate the problem. Come to find out, the float level & variable resistor assembly is pretty simple. The variable resistor is inside a small metal box which can be opened by bending back 3 tabs. Once it is opened you can see how the contact from the float arm wipes across the little resistor metal strip. On the unit from my car the metal strip had corroded and was giving an excessively high ohm reading. This is why the fuel gage read full for so long (I could travel 200 miles before the gage moved off of full). I used some very fine wet or dry emory cloth and carefully removed the corrosion from the metal strip and also the wiper contact.

I reassembled the unit and now it works perfectly!

By the way, if you want to buy a new sending unit, Gordon suggested that I should buy one for a '92 up as these were upgraded to a ceramic type unit.

 

There's still a Tech Tip on how to repair it, but I don't know if the photos are still there. It doesn't seem to matter if you have a Vette or a Pinto, all of these senders seem to run around $300! If you do a GOOGLE Search, you usually get a bunch of hits leading you to the individuals who have had this problem due to bad gas (too much sulphur). Shell seems to have the most problems/payouts for this condition, but there may be others too.

 

Hey, you maybe can get your fuel sender, filter and fuel pump replaced for free.......I just had mine done for free at a Chevy dealer and I even got ten bucks of free gas!!!!!
You were using Shell gasoline when they had that bad sulfur problem.....Well down here in South Florida Shell replaced everyones fuel pumps and everything for free if you said you used their fuel and filed a claim. So when my gauge gave me issues I took it in and the dealer reminded me that I used Shell gas and bada' bing...free fix and ten bucks free gas...

 

Well, I have had this car for about three weeks now and have never bought Shell gas. So, I could not go in and say that and feel right about it. If I was going to take the low road and the cheap way I would have bought a Mustang and not a Vette.

Tim

 

SIR, I HAVE THE DIRECTIONS AND DETAILED PICTURES IF YOU WISH. SEND ME AN E-MAIL VIA THIS SITE AND I WILL FORWARD THEM TO YOU.

 

I just replaced my fuel sending unit and fuel pump a month ago. Bought it here from the Corvette Forum ( and saved a lot ).
My fuel tank would always say that I was full. No matter how much fuel I really had. I was carrying around a brazing rod, just so I could dip my tank every day or so.

It can be pulled from the top of the fuel tank, without removing the fuel tank. Once I pulled the unit out from the tank, I noticed that the ground wire for the fuel gauge sending unit was loose. Since I had just purchased a sending unit that was known to be good, I installed it, instead of trying to re-solder the old one.

If you were to find that the ground wire on yours is loose, too, you may want to try re-soldering the wire. That way, all you are wasting is just your time, and a little effort. If it works, you saved a lot of money.

Since your symptoms sound like mine, it may be worth a shot.

Good luck!

 

Most of us have a 20 gallon tank but the gagues are not accurate. The last 1/2 of tank registeres fast and the first 1/2 real slow.

 

I wrote the tech article, and can email it with pics to anyone who wants it.

This is a $20 2 hour (max) repair. Go for it, it's nice to have a working fuel gauge.

ps....here it is without the pics.

https://www.corvetteforum.com/techti...=277&TopicID=2

 

YES FRIZLEFRAK DID AND IT IS A GOOD AND COMPREHENSIVE ARTICLE.

 

I would love to get a copy of it with pictures. Can you please send it to Rocket_Sapp at Hot mail.Com

Thanks Frizlefrak

Rocket

 

Well, They kinda helped me out as I just spent over $6 grand there on mods...some cheap way out huh....