Author Topic: Poping through Exhaust  (Read 1274 times)

Offline CUDA JAS

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Poping through Exhaust
« on: October 29, 2007 - 01:16:17 PM »
I started my car today :woo:. First time sice early summer.  :-\

I let the car idle and warm up.

I have two issues... 1. there is an intermitent pop coming out of the pass side exhaust and 2. The car hesitates and back fires through the carb when I bring it to W/O throtle quickly.

Are both of these timing related?

I have done all this with the car in park because there is no gas tank in it now. Should I be tuning under load?

Any help would be appreciated.

I can fix just about anything, it is just the diagnosing that I suck at!  
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Offline Chryco Psycho

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Re: Poping through Exhaust
« Reply #1 on: October 29, 2007 - 01:33:17 PM »
sounds more like a lean condition , try richening the mixture screws , or the accelerator pump is not pushing fuel in as the throttle is opened

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Offline CUDA JAS

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Re: Poping through Exhaust
« Reply #2 on: October 29, 2007 - 02:11:32 PM »
sounds more like a lean condition , try richening the mixture screws , or the accelerator pump is not pushing fuel in as the throttle is opened

Tha acell pump appears to be working, good fuel flow right as you crack the trotle (maybe to the point of a rich bog?)

The mixture screws..I assume that you mean the idle mixture srcews on the side of the primary metering block.

I am running a holley carb btw...probably should have mentioned that. ::)

Thanks,

Jas
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Offline Chryco Psycho

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Re: Poping through Exhaust
« Reply #3 on: October 29, 2007 - 02:32:04 PM »
yes the mixture screws are on the side of the metering block

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Offline MEK-Dangerfield

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Re: Poping through Exhaust
« Reply #4 on: October 29, 2007 - 06:34:59 PM »
Assuming you have the idle/fuel mixture screws right, it's really tough to diagnose when you are in park. I know my car seems to have a bog in park after "I think" it is warmed up, but it really takes a few minutes out on the road before the bog goes away.

Have you even set the timing yet? As Chryco mentioned, you could be running lean. How do your spark plugs look? If white, we have a winner.  :grinyes:


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Offline CUDA JAS

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Re: Poping through Exhaust
« Reply #5 on: October 29, 2007 - 07:28:26 PM »
Assuming you have the idle/fuel mixture screws right, it's really tough to diagnose when you are in park. I know my car seems to have a bog in park after "I think" it is warmed up, but it really takes a few minutes out on the road before the bog goes away.

Have you even set the timing yet? As Chryco mentioned, you could be running lean. How do your spark plugs look? If white, we have a winner.  :grinyes:
  Mike

I am pretty sure I do NOT have the mixture scews right.  I was trying to tune the idel mixture, but I am almost certain that they are not the same on each side, which would explain the poping on pass side only.  I am going to put them back to factory settings and try it again.

I tried to set the timing, but my timing marks are tough to read.  So am going to paint the balancer and install some timing tape and try it again.  The cam is pretty wild (old torker II cam) so it will be mostly trial and error to get the right timing.

As long as it starts and runs, I am good for now and will worry about the timing and tuning the carb once it is on the road.

Thanks for the help!

 
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Offline Chryco Psycho

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Re: Poping through Exhaust
« Reply #6 on: October 29, 2007 - 08:24:35 PM »
you will want the timing set 16-20* initial with the vacuum hose diconnected so ti doesn`t over advance with RPM
 mixture screws need to be turned out until rpm quits rising then turned in tu just where the rpm starts to drop & then turned back out about 1/4 turn
 the popping could also be a leak in the exhaust pipe on the right side

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Offline Bullitt-

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Re: Poping through Exhaust
« Reply #7 on: October 29, 2007 - 08:45:29 PM »
Just a thought seeing as the problem seems to be on the passenger side. If you have stock exhust manifolds could the heat riser be stuck closed?
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Offline CUDA JAS

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Re: Poping through Exhaust
« Reply #8 on: October 29, 2007 - 08:51:29 PM »
you will want the timing set 16-20* initial with the vacuum hose diconnected so ti doesn`t over advance with RPM
 mixture screws need to be turned out until rpm quits rising then turned in tu just where the rpm starts to drop & then turned back out about 1/4 turn
 the popping could also be a leak in the exhaust pipe on the right side

Wow that much intial.  I will give that a try.  That is idleing with the car in gear correct?

A leak in the exhaust is possible, car has sat for some time.

Just a thought seeing as the problem seems to be on the passenger side. If you have stock exhust manifolds could the heat riser be stuck closed?

Nope, running headers.
74 'cuda 360/727



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Offline 6packCuda

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Re: Poping through Exhaust
« Reply #9 on: October 29, 2007 - 08:59:10 PM »
Did it run ok the last time you ran it in early summer?
Dave

Offline Chryco Psycho

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Re: Poping through Exhaust
« Reply #10 on: October 29, 2007 - 09:39:56 PM »
generally I set timing idling out of gear

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Offline CUDA JAS

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Re: Poping through Exhaust
« Reply #11 on: November 14, 2007 - 10:57:22 AM »
Started the car on the weekend,  always a :grinyes:

I reset the mixture screws, and the poping has stopped.   :worshippy   Was definatley lean.

The hesitation is still there, but I have not played with the timing yet.

I painted the balancer and hope to put on some timing tape and reinstall the balancer, next weekend.  I will give it a try then!

Thanks for the help.

Jas


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Offline Chryco Psycho

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Re: Poping through Exhaust
« Reply #12 on: November 14, 2007 - 11:41:24 AM »
 :2thumbs:

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