Popping/back firing

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Jan 23, 2011 | 06:48 PM

speedracer2536

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Popping/back firing

So i drove my car for the first time today.. Has a nasty pop that sounds like its coming from one cyl.. Its kinda random though.. New opti and wires.. Mods are as follows..

mods are as follows..
new shortblock with arp rodbolts new bearings gaskets rings etc..
stage 3 ported heads
cc306 cam
1.6 rr
arp headbolts
new opti
csr elec. wp
new wires..

Jan 25, 2011 | 07:25 PM

ss.slp.ls1

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Quote:

Originally Posted by speedracer2536

Not really much to go off of with your "pop sound".
I am assuming you are tuned for the above mods?
RR's adjusted correctly?
SES light on?
GM brand opti?
Check for arching wires or wires touching the headers.

Jan 25, 2011 | 07:42 PM

onephatZ28

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+2 is it tuned?

Jan 25, 2011 | 07:45 PM

jim ravencraft

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Hi,
i agree with above post. Check wires/coil packs/sparkplugs. If you had coil packs off/ may have out of order/check wiring diagram-color code for proper sequence.vacuum test is easy checks for leaks/valves/timing/etc.
Have a blessed day........jim

Jan 25, 2011 | 11:34 PM

speedracer2536

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Yes it is tuned

Jan 26, 2011 | 03:14 AM

onephatZ28

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could b a bad plug, what opti do u have? i had a new opti take a **** on me after 50 miles

Jan 26, 2011 | 10:47 AM

speedracer2536

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This opti has idle time on it.. and is brand new.. its a chandler.. I went through the test on shbox's website and its functioning correctly.. Im thinking its the plugs.. I should get around to pulling them tonight..

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Jan 26, 2011 | 12:45 PM

speedracer2536

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yes its popping while accel... but it sounds more like one cyl.. didnt really drive it much as the neighbors came out thinking i was shooting a shotgun..

Jan 26, 2011 | 01:01 PM

#10

WhitePhoenix99

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Yeah.. you have a burnt plug wire I would say. Get under the car and check EACH one to see if they were making contact with your headers.

Jan 26, 2011 | 01:08 PM

#11

Fazz73jr

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Burnt wire or a couple wires crossed. Check the icm if that's not your problem. The icm was my problem when I had that problem.

Jan 26, 2011 | 03:46 PM

#12

speedracer2536

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ya im gonna for sure get new plugs.. It may be worth it to get new wires as well.. I will prob. go get my icm and coil tested just for ***** and giggle as well..

Jan 26, 2011 | 05:18 PM

#13

djjab57

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Quote:

Originally Posted by jim ravencraft

Coil packs ?!?! Really ?!?!

Jan 27, 2011 | 06:48 PM

#14

myltwon

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if you've had the problem immediately after installing the h/c setup I would say it's a timing problem like crossed wires, bad valve lash, improperly installed cam, etc.

Jan 28, 2011 | 08:08 PM

#15

speedracer2536

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This is a new motor.. i installed everything.. LOL im thinking bad plugs.. bad wires or valve lash..

Jan 28, 2011 | 08:20 PM

#16

myltwon

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Quote:

Originally Posted by speedracer2536

This is a new motor.. i installed everything.. LOL im thinking bad plugs.. bad wires or valve lash..

sound like this? that's what mine sounded like when I trusted my friend to install the cam itself and was off quite a bit of degrees on my cc503/stock heads setup a while ago.

http://www.streetfire.net/video/97-t...or_814291.htm#

Jan 29, 2011 | 09:19 AM

#17

speedracer2536

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Not really.. i installed the cam with the motor on the stand.. Dot to dot.. rotated the motor over 3 times and checked the placement of the dots each time and it was dead on.. This isn't my first build..

Jan 30, 2011 | 10:32 AM

#18

speedracer2536

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So i replaced all the plugs and it got better for aabout 5 min.. NO backfiring.. but now its back.. All my plugs looked like the plug on the right.. EXCEPT no. 8.. It looked clean but was coated in fuel.. It seems like the issue gets worse after it gets warm as well.. Im thinking ICM right now.. I already have a new set of wires on the way and im gonna go get the coil and icm tested today.. LMK if anyone else can think of anything.. I'm assuming that #8 isnt firing and that its shorting on a header..

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Jan 30, 2011 | 10:55 AM

#19

myltwon

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wasn't trying to say you would make such a simple mistake but when someone wants other people to help diagnose a car over the internet, you have to assume all possible scenarios until information proves otherwise.

as for the current condition, if only a single cylinder is having a firing problem that only occurs after running for a while I would rule out ICM and Coil personally.

are the injectors new on the car? I'd do a leak test on them either way (lift fuel rail, put key in on position and look for fuel drip)

also I would check for a vacuum leak around the #8 intake port.

Jan 30, 2011 | 11:43 AM

#20

speedracer2536

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It looked like the #8 cylinder wasnt firing at all.. the plug was just coated in fuel..

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