does the engine run ok other than popping a little when it is really cold out?
Quadrajet Making A Popping Sound
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Originally Posted By: tom slick
does the engine run ok other than popping a little when it is really cold out?
tom, once the engine is totally warmed up she runs fantastic, meaning once she is at normal temp there is no popping sounds.
Hopefully this choke adjustment should work. If we get a really warm day like 70 degrees or higher and I take the car out and there are no issues then this car will only be driven in the warm weather.
I took the car out 2 weeks ago when it was 72 degrees out and she started up and did not pop while the car was warming up.
I have to realize that since this car has shorty headers and a dual exhaust that she will take longer too warm up, if the temp is 70 degrees or higher she warms up quicker, the colder it is out, the longer it takes to warm up.
I just have a feeling that with a carburetor and headers you do not have the tube going from the manifold to the air cleaner which will help with warm ups, I remember being at a speed shop and watching the guys start up an old Dodge Charger with headers and she ran rough for a few minutes, this was in the winter time.
I have checked the thermostat and it is not stuck closed, I did the test in a hot pot of water on the stove.
does the engine run ok other than popping a little when it is really cold out?
tom, once the engine is totally warmed up she runs fantastic, meaning once she is at normal temp there is no popping sounds.
Hopefully this choke adjustment should work. If we get a really warm day like 70 degrees or higher and I take the car out and there are no issues then this car will only be driven in the warm weather.
I took the car out 2 weeks ago when it was 72 degrees out and she started up and did not pop while the car was warming up.
I have to realize that since this car has shorty headers and a dual exhaust that she will take longer too warm up, if the temp is 70 degrees or higher she warms up quicker, the colder it is out, the longer it takes to warm up.
I just have a feeling that with a carburetor and headers you do not have the tube going from the manifold to the air cleaner which will help with warm ups, I remember being at a speed shop and watching the guys start up an old Dodge Charger with headers and she ran rough for a few minutes, this was in the winter time.
I have checked the thermostat and it is not stuck closed, I did the test in a hot pot of water on the stove.
is it popping out the exhaust or through the carburetor?
Thats a great question Tom. I assumed popping through the carb, since all of my cold weather Q-jet experience has involved sneezing through the carb. If it is popping through the exhaust, that is a horse of a different color. Possible same causes, just a different direction, i.e. through carb=too lean, through exhaust=too rich.
When exactly does it pop through the exhaust, at idle, accell, decell?
When exactly does it pop through the exhaust, at idle, accell, decell?
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I thought he was talking about muffled backfires through the carb too.
If the misfires occur when you push the accelerator pedal under load ..then retreat when you back off, then I'd say it's a vaporization issue, aka choke. I'd normally look to bad wires or a plug or two that was fouled ..but since you indicate that they're new, I'll reject that for the moment.
Go find an functional OEM air cleaner and get the hose kit from JCW or whomever. 85F air after 30 seconds.
Your choke may not be able to be adjusted to keep a good fuel mixture for the duration of your warm up without the heat stove warming the intake air. They were designed to limit the fuel enrichment process.
Exhaust valves are easy to check. Take any old piece of paper to the exhaust. If it flaps around and stays off the tail pipe at idle ..fine. If it's whacking back against the pipe (if it's thin enough you can see the circle of the pipe through the paper) ..then you've got some exhaust valve leakage.
If the misfires occur when you push the accelerator pedal under load ..then retreat when you back off, then I'd say it's a vaporization issue, aka choke. I'd normally look to bad wires or a plug or two that was fouled ..but since you indicate that they're new, I'll reject that for the moment.
Go find an functional OEM air cleaner and get the hose kit from JCW or whomever. 85F air after 30 seconds.
Your choke may not be able to be adjusted to keep a good fuel mixture for the duration of your warm up without the heat stove warming the intake air. They were designed to limit the fuel enrichment process.
Exhaust valves are easy to check. Take any old piece of paper to the exhaust. If it flaps around and stays off the tail pipe at idle ..fine. If it's whacking back against the pipe (if it's thin enough you can see the circle of the pipe through the paper) ..then you've got some exhaust valve leakage.
I guess when you said it was running perfectly, it wasn't.
If the car is lacking power when it's popping I doubt it would be the header bolts. If you nail it, it pops and is lacking power it is either carb or engine related. I would check timing, the plugs, and compression, rule them out then fiddle with the carb again. Remember, you adjusted the choke a few times, and adjusted the air fuel mix a few times without success. You checked vacuum and said it was good, so we can hopefully rule that out.
Aren't older cars a hoot?
Edit to add:
How about trying to set up a hand choke to see what happens. The carb could be going bad too, and a hand choke would take the choke out of the equation.
Aren't older cars a hoot?
Edit to add:
How about trying to set up a hand choke to see what happens. The carb could be going bad too, and a hand choke would take the choke out of the equation.
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I talked to my friend at the speed shop and if I can't get this thing right he is going to check my timing.
He also said that he would look into setting up a hand choke since he thinks these electric chokes are worthless and are a pain to dial in.
He also said that he would look into setting up a hand choke since he thinks these electric chokes are worthless and are a pain to dial in.
A hand choke will rule the choke out. It could also be a bad carb. If you use a hand choke, are certain the engine is OK, no bad rings or valves, the timing is on, plugs, wires, etc are good, and the accelerator pump is good, then something is wrong with the carb. At that point I would have someone who knows what their doing rebuild it.
Oh yea lets not forget the air/fuel mix is properly set.
Oh yea lets not forget the air/fuel mix is properly set.
SUCCESS!
I adjusted the choke too stay on longer, the car started up and the choke went from closed too open in about 3 minutes.
There was a faint popping sound, so I richened each mixture screw a half turn. I got the vacuum gauge out and made sure I had good manifold vacuum.
I took the car for a ride and she was fine, the temperature outside was about 48 degrees.
I did have 2 header bolts that were slightly loose, I tightened them down and made sure everything else was fine.
I adjusted the choke too stay on longer, the car started up and the choke went from closed too open in about 3 minutes.
There was a faint popping sound, so I richened each mixture screw a half turn. I got the vacuum gauge out and made sure I had good manifold vacuum.
I took the car for a ride and she was fine, the temperature outside was about 48 degrees.
I did have 2 header bolts that were slightly loose, I tightened them down and made sure everything else was fine.
1/2 turn is a lot, especially if it was set up with a vacuum gauge recently as you mentioned. There are a lot of variables here, and it is hard to determine which one is causing your issues, because now the choke and air fuel has been changed again.
A point of info: Once the engine is hot, and the air fuel mixture is set properly that would not be the cause of the popping, unless the needle valves or seats are bad, making a proper adjustment impossible. Have you checked them?
I would also check the things I mentioned above and rule them out. My gut is telling me the next big swing in temps either hot or cold is going to give you a headache again.
A point of info: Once the engine is hot, and the air fuel mixture is set properly that would not be the cause of the popping, unless the needle valves or seats are bad, making a proper adjustment impossible. Have you checked them?
I would also check the things I mentioned above and rule them out. My gut is telling me the next big swing in temps either hot or cold is going to give you a headache again.
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I went ahead and took the car out on Saturday night since my Dad needed to use my Marauder. It was 40 degrees outside when I left the house.
The car started up fine, I let it warm up for a minute, and she drove away fine. No stumbles, bogs, popping sounds. The car runs very smooth, and I took it out on Sunday when the temp was about 61 degrees and she was fine.
The car started up fine, I let it warm up for a minute, and she drove away fine. No stumbles, bogs, popping sounds. The car runs very smooth, and I took it out on Sunday when the temp was about 61 degrees and she was fine.
I bet you had some moisture in the fuel.
The carb is last on the list of adjustments.
EVERYTHING else should be right first, THEN adjust the carb.
EVERYTHING else should be right first, THEN adjust the carb.
Sounds like you've got it fixed, c3po; good job!
Originally Posted By: flanso
Sounds like you've got it fixed, c3po; good job!
I knew that if I kept at it I would get it fixed, I will probably pick up a book about Quadrajets since I cannot trust any mechanic in my area to fix mine.
I talked to a guy at a speed shop and everyone now seems to be running Hollies.
Sounds like you've got it fixed, c3po; good job!
I knew that if I kept at it I would get it fixed, I will probably pick up a book about Quadrajets since I cannot trust any mechanic in my area to fix mine.
I talked to a guy at a speed shop and everyone now seems to be running Hollies.
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