I keep a log of everything that I do to the car, and I have noticed that the intown gas mileage has dropped from a constant 14 mph to 8 mph for the last two tanks. I have also noticed that the exhaust seems to smell rich after i turn it off. I did a quick check under the hood tonight a see nothing wrong. PVC is connected , choke appears to be functioning. This is a 300/327 with a year old edelbrock 600 cfm carb. The power level seems fine. No hard start or run on issues. No back fires. Nothing has been modified to the car other than a oil change in 6 months. What could case this condition. Where should I start checking?
Vacuum piston not working right? Pull the air cleaner off, and make sure its all the way down at idle. Might have got some shit in there, causing it to stick in the up position.
Check the color of your tailpipes-should be a grey color. If black, then the carb is running rich. These conditions are only if you are getting out on the highway for 10 miles or so. Around town the accelerator pump & stop & go traffic will keep it too rich to diagnose by looking at the tailpipes.
What a let down ,after reading your title, I thought you may have found a big bag of cash. Good luck with your fuel problem. >...........Jack
Too much fuel or too little air. I would check the air side first..air cleaner clean and unobstructed?
Don't get me started ..... but, when you said "Edelbrock carb" .... well .... let's just say "I am not a fan" of those.
Choke not opening right or all the way. Dirt under needle or needle sticking. Vacuum piston not working as previously mentioned. Timing off for some reason. You might want to check the vacuum advance to make sure it is working right as that would cause the timing advance to be less than desired.
Well I did some investigating. I guess I had a small pin hole in the line from the carb to the distributor.I measured a vacuum of 21 at the carb but just for grins I measured the other end of the line and it only read 7. So im guessing I developed a small vacuum leak that was causing me to run rich. Thanks for the tips and I will update to let everyone know if that was it.
Good to hear ykp. I've seen this too, they run a higher ethanol content in the winter. May be contributing to your problem. Ever notice how gas drops way down in price when it starts to get cold?
You are probably riding around with your left foot on the brake, remove your foot and you will be right back to 14 mph just like before.
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