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Discussion Starter #1
I can hear a pop in the exhaust on the passenger side as one of the cylinder is missing once in a while, as soon as it is warmed up no more pop. The distributor is new, the plugs are new. Could it be the plug wires? Why no pop when it reaches temperature?
 

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I will suggest that you have an exhaust leak, and when the engine warms up, the metals expand and the leak is sealed.

Once the engine cools down, the process starts all over again.
 

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Discussion Starter #3
I will suggest that you have an exhaust leak, and when the engine warms up, the metals expand and the leak is sealed.

Once the engine cools down, the process starts all over again.
Interesting I did think about an exhaust leak.
 

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What Derald said.
 

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Discussion Starter #6
Could be an exhaust leak. Do you have any logs from your Fitech? Could be a DECCEL setting.
The poping happens at idle so deccel should not be an issue, right?
 

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If you are talking about cold idle with out ever rising the rpms...then yes DECCEL is not involved. ACCEL is used during idle control and uses a temp curve to determine how much fuel should be used at idle. You should be able to see ACCEL with different temp level settings on the default curve in you hand held.
Before making any changes to the cold settings you should make sure the IAC is between 3 - 10 during warm idle. If not fix this first.

Data logging from a cold start should tell you more what’s happening during this popping. If you don’t know how to use data logging, there use to be some videos on how use it on YouTube.

You can also, if you know the side that is popping, pull a couple plugs and see if it’s running or burning rich which could be a plug issue.
Good luck.
Rich
 

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Discussion Starter #8
Getting ready to get the car out of hibernation and still trying to find the source of that problem. I pulled the plugs on PS and found 3 of them rich and #4 lean, looked for vacuum leak found nothing...still scratching my head, I’ll do a data log and post it
 

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Where do you have your O2 sensor? If you have it in one of the header pipes, would it be the one indicating lean on the spark plug? I suggest you pull and check all the plugs.
If you are positive you have no vacuum leaks then I would pull the valve cover and check the valve movement on the lean cylinder.

Good Luck

Norm
 

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Discussion Starter #10
I have the O2 sensor on the DS header and the lean cylinder is on PS
 

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I have the O2 sensor on the DS header and the lean cylinder is on PS
Well that almost for sure rules out the easy stuff. It could still be an exhaust leak and I would check that first. I would still pull the plugs on the driver’s side to see if they match the rich plugs on the pax side. The only things that I can think of that could cause it to lean out while all the others are running rich are a vacuum leak at the manifold gasket or something wrong in the valve train on that cylinder. Maybe a call to Levy is in order or someone smarter than me has another idea.
 

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Correct me if I'm wrong on the newer engine set-ups but the O2 sensor controls one bank, not one cylinder. If one plug on one bank is lean and the others are rich then it has to be due to something particular with that cylinder, like the plug, the plug wire, the distributor cap, the fuel injector, one of the valves, one of the lifters, the rings, a gasket problem or a crack in either the block or head. I'd suspect the plug or wire first.

Regards, Rick.
 

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When checking for exhaust leaks, also check to make sure that you don't have a cracked header where it comes out of the flange. I cracked mine - twice on #1. A friend's car did the exact same thing in the same place. Look for some black soot marks and that tell-tale clicking sound.
 

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Discussion Starter #15
When checking for exhaust leaks, also check to make sure that you don't have a cracked header where it comes out of the flange. I cracked mine - twice on #1. A friend's car did the exact same thing in the same place. Look for some black soot marks and that tell-tale clicking sound.
It is not a clicking sound it is more like a pop coming from the side pipe
 

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It is not a clicking sound it is more like a pop coming from the side pipe
I think he is talking about, at the point of the leak. An old trick is to use a length of hose, from your ear around the header attachment points and you will easily hear if it is leaking.
 
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