Breaking up under hard acceleration
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Breaking up under hard acceleration
1968 327 350horsepower
Completely restored, everything is new
Put 550 miles on the car last year, no problems .
This year runs fine until you push it hard and then it breaks up at 3500 -4000 RPM.
Could it be bad fuel, ignition(everything is new, wires, points, condensor)clogged fuel filter???
What say you all?
Thanks
Kurt
Completely restored, everything is new
Put 550 miles on the car last year, no problems .
This year runs fine until you push it hard and then it breaks up at 3500 -4000 RPM.
Could it be bad fuel, ignition(everything is new, wires, points, condensor)clogged fuel filter???
What say you all?
Thanks
Kurt
Burning Brakes
Joined: Jan 2007
Posts: 1,164
Likes: 1
From: Port Clinton Ohio
St. Jude Donor '08-'09-'10-'11-'12-'13
Mine is doing the same thing. Runs great until it gets to about 4000rpm. Then it totally loses power. Let off the gas and it runs fine again. It has a GM performance 330hp 350 engine with quadrajet. Fuel pump was new last year. I've replaced the s shaped hose that goes from the steel fuel line to the pump, the fuel filter inside the carb, and removed the sock around the fuel pickup in the tank. Plugs and coil are new and the distributor was rebuilt by Lars just before he retired. When I pulled the plugs, the electrodes were white. I think that means a lean condition.
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
War Bonnet,
When you say fuel sender sleeve, are you referring to the sleeve over the gas pickup tube inside the gas tank or are you referring to something else?
Can the sleeve in the tank be replaced without dropping the tank or removing the entire pickup unit?
Thanks,
Kurt
When you say fuel sender sleeve, are you referring to the sleeve over the gas pickup tube inside the gas tank or are you referring to something else?
Can the sleeve in the tank be replaced without dropping the tank or removing the entire pickup unit?
Thanks,
Kurt
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
Ya, I think he means the sock thing at the end of the fuel sending unit pickup where the gas gets sucked up. Just roll up your sleeve and reach into your gas tank. Seems like many of us have had the same problem and it can be difficult to track down. Mine runs fine around town, even when I get on it, but under extreme acceleration will sometimes cut out, cough, bog, at high rpm. Difficult to test.
Race Director
Joined: Jun 2005
Posts: 10,189
Likes: 206
2018 Corvette of Year Finalist
2017 C3 of Year
War Bonnet,
When you say fuel sender sleeve, are you referring to the sleeve over the gas pickup tube inside the gas tank or are you referring to something else?
Can the sleeve in the tank be replaced without dropping the tank or removing the entire pickup unit?
Thanks,
Kurt
When you say fuel sender sleeve, are you referring to the sleeve over the gas pickup tube inside the gas tank or are you referring to something else?
Can the sleeve in the tank be replaced without dropping the tank or removing the entire pickup unit?
Thanks,
Kurt
A way to check the tank/sender or at least how I found the problem was to connect a 2 1/2 gal gas can to a 10' piece of fuel line. Now connect that to the inlet at the fuel pump, thus eliminating the gas tank and lines. Take the car for a ride (with the gas can in the passenger seat) see if the problem is resolved. I then tested the lines by installing the fuel line in the rear at the tank, take the car out again. That showed me my problem was in the tank. My arm can not fit into the neck so I syphoned out the gas, dropped the fuel sender and replaced it, no more problem!
Here's what I found!
WB
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Safety Car
Joined: Feb 2006
Posts: 3,557
Likes: 0
From: Ridgeway VA
Another thought since I had the same problem. Check the modulator valve on the tranny. The metal tube on the back of the manifold goes to the modulator valve on the tranny and if clogged it can effect performance.
