I am having difficulty with what I think is poor fuel flow. I have a 1967 corvette with a 1964 engine and (4 spd Muncie) transmission. I have a four barrel Carter (WCFB) carburetor on it. My primary symptom is the loss of power; it feels like the engine is starved of fuel. The engine sort of pulsates, almost like it's chugging. I have done many things from carb rebuild, inline fuel filter replacement, fuel line replacement, fuel pump replacement, cleaned fuel tank, new sock, new points and condenser, to name some of the more obvious things I have done. I have had many suggestions that I have had checked out such as a flat cam (none found), in addition to the above changes. I have the problem always when I am pushing hard on the throttle around 55 mph in 3rd and 4th gear. If I back off on the throttle it appears to smooth out. Also, I get it if I go through the gears at high throttle as though I am drag racing the car and then I get it in all gears. I also get it when I take a sharp turn pushing hard on the throttle. The car starts, idles, and runs great as long as I do not push hard on the throttle. It always happens when I enter traffic as I try to merge with traffic. It is embarassing as I cannot move ahead as I should. Here is my question. I replaced the tank sock and when I look at it I notice that it is fine except that the last two inches or so is flat against the tank bottom with a little kink in it. I dont know if this is a problem as I dont know how it should look. Should it be touching the tank bottom? Or, should it be perfectly straight? Is this little kink preventing gas from going into the sender unimpeded? Right now the sock is at a diagonal on the sender pickup and then bends where it comes in contact with the tank bottom. Can someone tell me if this is normal or possibly the cause of my problem? Thanks, Rick.
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Re: Fuel Sock in a 1967
Thanks, Joe. I have performed this task (putting gas senders in the tank) several times and really never looked in the tank to see how it laid. I am grasping to find out what causes my fuel decline (assuming that is what it is) and I thought it might be the sock. On to other hypotheses. RickComment
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Re: Fuel Sock in a 1967
As Joe says, situation normal. Here's what I think is the original on my late '65. No fuel starvation problems.
xComment
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Re: Fuel Sock in a 1967
Rick,
Go after the easy stuff first, fuel bowl level, timing, timing advance cannister working? Is dwell to tight? What are carb jets size? Does it lean surge? You say "The engine sort of pulsates, almost like it's chugging" do you think surge? That is lean condition.Comment
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Re: Fuel Sock in a 1967
Nikon Coolpix S4, only 2_9/16" high, and a lens barrel that you can rotate through 270 degrees. But what made this shot really easy is that I had the tank out and the filler neck off, and you can see by the atached pic that I have lots of room.
nComment
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Re: Fuel Sock in a 1967
Richard,
So the problem manifests itself when the engine is put under load. Does the problem occur when the choke plate is still closed? If you have a spare ignition coil try swaping it out to eliminate that as a possible cause and how ols are the spark plugs and wires.Comment
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Re: Fuel Sock in a 1967
Ya, great pic! My sock is up further on the stem of the sender. I would say there is only about two inches that are not on the stem and this is where it lays on the floor of the tank (where the "kink" is). Should I pull the sock down more so more of it is on the floor? I might try this anyway. My elec choke works fine as it opens as the engine warms and idles fine. I have not changed the coil this Spring (it was a brand new delco-remy last year). However, another person recommended this as the coil put out more juice under load and maybe it is not functioning properly. As for the symptoms, you have to drive it to really understand. My gift for telling is limited. My best analogy would be it feels as though someone has pinced my fuel line and then released it only to pinch it again. And, it only happens under load particularly at high speeds, 55 and up. When entering the freeway I cannot "goose it" w/o the intermittent acceleration, slow down; acceleration, slow down. When I push more gradually on the accelerator it seems to smooth out. It runs great in local street traffic and I can accelerate fine. Thanks so much for the FB. Ill try a few more things and let you know. RickComment
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Re: Fuel Sock in a 1967
Richard:
There are some post/stories in the archives that address this issue. Often the new, replacement fuel sock has a natural/permanent fold or crease in the sock. If during installation this crease is accidently positioned so it covers the fuel line opening, it can restrict fuel flow to the fuel pump and carb. The solution is to reposition the fuel sock on the fuel line so that this does not reoccur.
I know that I paid special attention to this when I replaced my gas tank a few years ago. It appears to have paid off............as I do not have this problem with my car.
Something to check into. LarryComment
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Re: Fuel Sock in a 1967
Richard,
If that's one of those reproduction Delco Remy coils, change it to test and let us know.Comment
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Re: Fuel Sock in a 1967
Chapter 1
Here's the way to cure the sock problem! If it is indeed a sock problem! Take the sock out and throw it away!!!!! It only filters out the big stuff anyway. If that fixes the problem you have you can rest assured it was the sock!
Chapter 2
I'm betting that you have a non stock cam, headers, al intake etc. etc. Well that old WCFB ain't gonna feed that hot rod stuff!!! Get you a carb that will!
JRComment
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Re: Fuel Sock in a 1967
I wanted to let all that gave me suggestions about my hesitation problem that it was the carburetor after all. I replaced the fuel pump, fuel lines, fuel filters, coil, points and condenser, and I had the distributor rebuilt all to no avail (plus numerous other checks such as the fuel sock). The clincher was the distributor as the weights were bad, there was play in the shaft, and there was a crack in the base holding the weights. When this did not fix the problem, my carb guy took the carb again and this time found several problems with crud in the carb (he blamed on my using seafoam over the winter) and a bad accelerator pump. He also adjusted the floats to run richer. My car now runs much better. By the way, I have this carb (Carter Wcfb) as it was used in 63-64 and matches my 64 engine. I might try to sell the engine after I post it to see if it might belong to someone that has the matching car. I might then try to find a 67 engine for my 67 car. Thanks again for all your assistance and suggestions. RickComment
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Re: Fuel Sock in a 1967
Hi Rick,
Glad you found the problem. We had a very similar problem with our 67 L-79 right after we received our rebuilt 3810 Holley back. After going through many possibilities our fix was replacing the spark plugs. Its been running right as rain since then.
ChuckComment
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