'76 Tank / Sending unit Question.
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Joined: May 2006
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From: Schenectady New York
'76 Tank / Sending unit Question.
Howdy guys. I went to start my baby after the snow melted a few days ago, pulled open the cover, opened the garage, re-hooked the battery...
Turned the key ... and ... well .. no ignition.
It rotates, no starting though. I added 2 gallons of gas (knowing that last year I had a minor tank leak toward the end of autumn,) tried again... nothing. I checked my haines manual, did the routine, pump the gas 2 dozen times, manually played with my choke etc. I noticed after even all of this, I didn't get my usual gas smell from my carb, so I pulled my gas line out, and saw it was bone dry. 
Long story short (too late) I have convinced myself this is a problem with my fuel sending unit, however, if this is indeed the case, and knowing my tank had already previously had problems, I am wondering when I drop the tank if it would be possible to just put in a non-repro tank and sending unit without any major modifications or if I am forced to stretch the very limited college budget on a reproduction.
Any help or advice would be greatly appreciated, and thank you again for your time guys.
Turned the key ... and ... well .. no ignition.
It rotates, no starting though. I added 2 gallons of gas (knowing that last year I had a minor tank leak toward the end of autumn,) tried again... nothing. I checked my haines manual, did the routine, pump the gas 2 dozen times, manually played with my choke etc. I noticed after even all of this, I didn't get my usual gas smell from my carb, so I pulled my gas line out, and saw it was bone dry. Long story short (too late) I have convinced myself this is a problem with my fuel sending unit, however, if this is indeed the case, and knowing my tank had already previously had problems, I am wondering when I drop the tank if it would be possible to just put in a non-repro tank and sending unit without any major modifications or if I am forced to stretch the very limited college budget on a reproduction.
Any help or advice would be greatly appreciated, and thank you again for your time guys.
Last edited by Fatty_VM; Apr 9, 2008 at 10:32 PM. Reason: spelling and smilies
Drifting
Joined: Feb 2005
Posts: 1,438
Likes: 2
From: Melrose Florida
NO WAY a no-start condition is related to the fuel gauge or sender.
Most likely the fuel pump lost its prime over the winter (via evaporation), and needs some cranking/vacuum developed to get fule to the pump, and on to the carburetor.
Use quick start, or gas in the carb, to get it to fire, this will develop enough vacuum to pull the gas through the lines.
Definitely check your rotor, cap, and plugs, to ensure a hot spark.
Steve
Most likely the fuel pump lost its prime over the winter (via evaporation), and needs some cranking/vacuum developed to get fule to the pump, and on to the carburetor.
Use quick start, or gas in the carb, to get it to fire, this will develop enough vacuum to pull the gas through the lines.
Definitely check your rotor, cap, and plugs, to ensure a hot spark.
Steve
Thread Starter
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Joined: May 2006
Posts: 50
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From: Schenectady New York
NO WAY a no-start condition is related to the fuel gauge or sender.
Most likely the fuel pump lost its prime over the winter (via evaporation), and needs some cranking/vacuum developed to get fule to the pump, and on to the carburetor.
Use quick start, or gas in the carb, to get it to fire, this will develop enough vacuum to pull the gas through the lines.
Definitely check your rotor, cap, and plugs, to ensure a hot spark.
Steve
Most likely the fuel pump lost its prime over the winter (via evaporation), and needs some cranking/vacuum developed to get fule to the pump, and on to the carburetor.
Use quick start, or gas in the carb, to get it to fire, this will develop enough vacuum to pull the gas through the lines.
Definitely check your rotor, cap, and plugs, to ensure a hot spark.
Steve
GD - Fuses seem ok, The gauge moves, but I never look at my gauges as being even 25% accurate
This is my last resort (the sending unit and tank)Durango - wow, I neglected to check, I'll pull it tonight and see.
Halfmoon - I've tried some off the shelf carb starter (spray stuff, seems like it's almost like grill starter fluid) Cap, plugs and rotor should be alright. I'll try direct gas in the carb (have never done it before..) the fuel pump just might be it.
Either way, let me experiment tonight and get back to you all. Thank you very much though for the help guys regardless =). :o
btw, does anyone know offhand if it's ok to swap tanks and sending systems anyway (for future reference)
Drifting
Joined: Feb 2005
Posts: 1,438
Likes: 2
From: Melrose Florida
Halfmoon - I've tried some off the shelf carb starter (spray stuff, seems like it's almost like grill starter fluid) Cap, plugs and rotor should be alright. I'll try direct gas in the carb (have never done it before..) the fuel pump just might be it.
btw, does anyone know offhand if it's ok to swap tanks and sending systems anyway (for future reference)
btw, does anyone know offhand if it's ok to swap tanks and sending systems anyway (for future reference)
Try also attaching a long piece of fuel hose (3/8") to the engine end of the long steel fuel line from the tank, suck on it a few times while holding down near the ground, you should be able to get the fuel flowing out of the tank and through the lines, maybe a little gummed up at the tank or in the lines, but it should flow with a little persuasion.
Feel free to swap tanks and sending systems...a lot of work for components that don't seem to be involved.
Steve
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From: Schenectady New York
If it doesn't fire on quick start, then it is a SPARK problem. If it fires and runs just long enough to burn the quick start (or gas in carb), then it is a FUEL DELIVERY problem, either pump (maybe not bad, just no fuel at pump) or lines.
Try also attaching a long piece of fuel hose (3/8") to the engine end of the long steel fuel line from the tank, suck on it a few times while holding down near the ground, you should be able to get the fuel flowing out of the tank and through the lines, maybe a little gummed up at the tank or in the lines, but it should flow with a little persuasion.
Feel free to swap tanks and sending systems...a lot of work for components that don't seem to be involved.
Steve
Try also attaching a long piece of fuel hose (3/8") to the engine end of the long steel fuel line from the tank, suck on it a few times while holding down near the ground, you should be able to get the fuel flowing out of the tank and through the lines, maybe a little gummed up at the tank or in the lines, but it should flow with a little persuasion.
Feel free to swap tanks and sending systems...a lot of work for components that don't seem to be involved.
Steve
Thanks for the help Steve
I'll be back tonight with updates and 
for any further advice. 
Thread Starter
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Joined: May 2006
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From: Schenectady New York
ok, checked my fuel pump and lines .. they are still bone dry. It's not a sparking problem either....
Brought it down to my mechanic, he had an electric pump laying around, we hooked it up .... it could pull nothing.
Ok, line of thinking NOW it IS my sending unit or something gumming up my tank itself.
But as I was talking to him, he sounded unsure of putting any 'ol tank up there. Said something along the lines of the tank and units being special made for the years ... is this really true? I thought the response was that anything could really go up there as long as it wasn't too big.
What say you corvette gods?
Brought it down to my mechanic, he had an electric pump laying around, we hooked it up .... it could pull nothing.
Ok, line of thinking NOW it IS my sending unit or something gumming up my tank itself.
But as I was talking to him, he sounded unsure of putting any 'ol tank up there. Said something along the lines of the tank and units being special made for the years ... is this really true? I thought the response was that anything could really go up there as long as it wasn't too big.
What say you corvette gods?
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Team Owner
Joined: Aug 2006
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From: Columbia Missouri
The mounting position is relatively specific to your year.
I have a feeling it's your pump. It's cheap and easy to install. Then if that doesn't work, drop the tank.
Now, something to consider, you'll likely be able to solve the problem by dropping the gas tank and evaluating everything you have. You'll be able to see if your lines are all still in good shape, if the bladder is okay, and if something is wrong or blocking fuel.
You'll have to buy all new rubber lines, S/S if you have the money, and just check out the actuation of the assembly in the tank.
I have a feeling it's your pump. It's cheap and easy to install. Then if that doesn't work, drop the tank.
Now, something to consider, you'll likely be able to solve the problem by dropping the gas tank and evaluating everything you have. You'll be able to see if your lines are all still in good shape, if the bladder is okay, and if something is wrong or blocking fuel.
You'll have to buy all new rubber lines, S/S if you have the money, and just check out the actuation of the assembly in the tank.
Team Owner
Joined: Aug 2000
Posts: 21,457
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From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
But as I was talking to him, he sounded unsure of putting any 'ol tank up there. Said something along the lines of the tank and units being special made for the years ... is this really true? I thought the response was that anything could really go up there as long as it wasn't too big.
What say you corvette gods?
What say you corvette gods?
Race Director
Joined: Apr 1999
Posts: 15,143
Likes: 477
From: NM
...not a Corvette God by any means, but 1975-1977 Corvette fuel tanks have a "rubber bladder" in them originally. These bladders over the years are collapsing and deforming inside the tank itself. It is remotely possible that the bladder itself could be blocking the pick-up tube or the bladder developed a hole and the fuel is between the bladder and tank itself. I removed my '75's bladder in '94 and it's been that way ever since. You should be able to take a flashlight(with the fuel cap off)and look down to see if fuel is covering the sock(intank fuel filter)or the sock itself could be so clogged it's not letting any fuel pass through.
What he said.
Burning Brakes
Joined: May 2005
Posts: 1,145
Likes: 5
From: South of London, Engerland
My '76 had a filter between the tank and the chassis fuel lines, at the back of the car. I had to remove the tank to discover it. I had running problems with my car for months before I discovered this filter and the cracked pipes that it was connected to. I removed the filter and replaced the rubber pipes and it's been good since.
This filter in my car was blocked, so when the fuel pump was sucking hard on the fuel lines, it was drawing air into the pipe through weaknesses in the old perished rubber fuel lines after this filter.
Dropping the tank and checking the condition of these neglected pipes and filter will cost you nothing except some time and might save you all sorts of trouble. That's what I'd do, I think.
You can see into the tank with a torch (don't drop it
) so check the condition of the fuel pick-up sock visually too. Don't worry about the gauge/sender yet - it can't be the cause of the problem, as someone said above.
This filter in my car was blocked, so when the fuel pump was sucking hard on the fuel lines, it was drawing air into the pipe through weaknesses in the old perished rubber fuel lines after this filter.
Dropping the tank and checking the condition of these neglected pipes and filter will cost you nothing except some time and might save you all sorts of trouble. That's what I'd do, I think.
You can see into the tank with a torch (don't drop it
) so check the condition of the fuel pick-up sock visually too. Don't worry about the gauge/sender yet - it can't be the cause of the problem, as someone said above.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
My '76 had a filter between the tank and the chassis fuel lines, at the back of the car. I had to remove the tank to discover it. I had running problems with my car for months before I discovered this filter and the cracked pipes that it was connected to. I removed the filter and replaced the rubber pipes and it's been good since.
This filter in my car was blocked, so when the fuel pump was sucking hard on the fuel lines, it was drawing air into the pipe through weaknesses in the old perished rubber fuel lines after this filter.
Dropping the tank and checking the condition of these neglected pipes and filter will cost you nothing except some time and might save you all sorts of trouble. That's what I'd do, I think.
You can see into the tank with a torch (don't drop it ) so check the condition of the fuel pick-up sock visually too. Don't worry about the gauge/sender yet - it can't be the cause of the problem, as someone said above.
This filter in my car was blocked, so when the fuel pump was sucking hard on the fuel lines, it was drawing air into the pipe through weaknesses in the old perished rubber fuel lines after this filter.
Dropping the tank and checking the condition of these neglected pipes and filter will cost you nothing except some time and might save you all sorts of trouble. That's what I'd do, I think.
You can see into the tank with a torch (don't drop it
) so check the condition of the fuel pick-up sock visually too. Don't worry about the gauge/sender yet - it can't be the cause of the problem, as someone said above. But in the US we call it a flashlight. Torch usually refers to something with fire here.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
You mentioned in your first post that you had a minor gas tank leak. There is no such thing as a minor gas tank leak. If you smell gas you have to find the source of the leak. Possible effects of a gas leak are: burning your house down if you store your Vette in a garage near a furnace, or burning the car up when the leaking gas catches fire on the exhaust system.
You may have a clogged fuel line - if you have a leak there might very well be rust in the tank or lines or a rotted hose sucking in air, but you really need to get under the car and find out where the leak is coming from.
Rick B.
You may have a clogged fuel line - if you have a leak there might very well be rust in the tank or lines or a rotted hose sucking in air, but you really need to get under the car and find out where the leak is coming from.
Rick B.
Burning Brakes
Joined: May 2005
Posts: 1,145
Likes: 5
From: South of London, Engerland
Thanks for the clarification. Will try to remember that one. We brits have a few weird ones to remember: What you call fenders, we call "wings". I have no idea why
And don't even get me started on tramp => bum => fanny => vagina
Last edited by BenUK; Apr 17, 2008 at 06:23 AM.
Thread Starter
Advanced
Joined: May 2006
Posts: 50
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From: Schenectady New York
...not a Corvette God by any means, but 1975-1977 Corvette fuel tanks have a "rubber bladder" in them originally. These bladders over the years are collapsing and deforming inside the tank itself. It is remotely possible that the bladder itself could be blocking the pick-up tube or the bladder developed a hole and the fuel is between the bladder and tank itself. I removed my '75's bladder in '94 and it's been that way ever since. You should be able to take a flashlight(with the fuel cap off)and look down to see if fuel is covering the sock(intank fuel filter)or the sock itself could be so clogged it's not letting any fuel pass through.
Paul, you hit the nail on the head, I added a ton more fuel cleaner, and dropped it off at my mechanic who worked his mumbo jumbo (using a funny looking snake with suction) and managed to get this sock gas permeable again.
Thank you everyone for all of your help again, every one of you did me a great deal of help by your suggestions. i hope in the future I am able to do the same
.
Originally Posted by 1981Z06Vette and BenUK
But in the US we call it a flashlight. Torch usually refers to something with fire here.
I knew what he meant, but that could be VERY bad!!!
I knew what he meant, but that could be VERY bad!!!
Last edited by Fatty_VM; Apr 17, 2008 at 07:27 AM.
Team Owner
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From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
...I stumbled upon my "bladder issues" quite by accident. Was going to a car cruise-in in the summer of '94 about 40 miles away. Bladder was "deforming" inside the tank itself and with the gas gauge showing about 3/8 tank and 20mi away from the cruise-in going 70mph on the expressway, car quit deader than a doornail. The bladder was deformed to the point where it was actually holding the gauge float up in the air showing the 3/8 tank of fuel, but yet I ran the car til the tank was bone dry.
