How can I cure the odd misfire at idle?
07-22-2003, 01:31 PM
#1
Drifting
Thread Starter
How can I cure the odd misfire at idle?
At idle, every one to three seconds I get a dull air burst *pup* sound out of my tailpipes. It happens on both sides (dual exhaust). My mechanic suspects its the odd misfire and he says it can be hard to get rid of. Is this common for a 26 year old 350? Is this a symptom of running too lean? I heard that running hotter spark plugs could help. Any comments are greatly appreciated.
[Modified by Boofers, 12:32 PM 7/22/2003]
[Modified by Boofers, 12:32 PM 7/22/2003]
07-22-2003, 01:42 PM
#2
Re: How can I cure the odd misfire at idle? (Boofers)
You've obviously never heard the idle of an L82. :lol: chugga chugga thumpity lope lope
Does it really bother you that much? I've had perfectly running fuel injected cars do that. You might be running a little rich, but honestly if it's as minor as you describe I wouldn't even bother trying to tune it away if it's running right in the rest of the RPM range.
That's a beautiful color by the way. It looks awesome with those wheels. You're making me rethink my plans for black paint.
Does it really bother you that much? I've had perfectly running fuel injected cars do that. You might be running a little rich, but honestly if it's as minor as you describe I wouldn't even bother trying to tune it away if it's running right in the rest of the RPM range.
That's a beautiful color by the way. It looks awesome with those wheels. You're making me rethink my plans for black paint.
07-22-2003, 01:53 PM
#3
Drifting
Thread Starter
Re: How can I cure the odd misfire at idle? (wcsinx)
Well it doesn't bother me a lot but I just want my car to be as good as it can be... :rolleyes: :D
Thanks for the compliment!
Thanks for the compliment!
07-22-2003, 02:12 PM
#5
Drifting
Thread Starter
Re: How can I cure the odd misfire at idle? (pws69)
Plugs, wires, cap & rotor all have less than 1000 miles on them. Ignition module has less than 500 miles. I was thinking new ignition coil or maybe my pickup coil?
[Modified by Boofers, 1:16 PM 7/22/2003]
[Modified by Boofers, 1:16 PM 7/22/2003]
07-22-2003, 02:13 PM
#6
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Re: How can I cure the odd misfire at idle? (Boofers)
my 79 L-82 does this as well. I have been unable to find it-changed plugs, plug wires, carb, manifold etc. and its still there. i ignore it.
p.s. the "pop" was not my reason for changing all of those things-im not that obsessive :D
p.s. the "pop" was not my reason for changing all of those things-im not that obsessive :D
07-22-2003, 02:18 PM
#7
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Re: How can I cure the odd misfire at idle? (nicecurves79)
try working with the idle mixture. It may be lean. Just remember how many turns of the screwdriver you add, so you can go back if you want.
07-22-2003, 06:33 PM
#8
Drifting
Thread Starter
Re: How can I cure the odd misfire at idle? (BSeery)
Yup, richened the carb up by changing my stock primary rods from size 52 to size 48, and adjusted idle mixture screws. I still get my 'misfires'. My friend has a spare performance ignition coil I'll try that out and see if it makes any difference.
[Modified by Boofers, 5:34 PM 7/22/2003]
[Modified by Boofers, 5:34 PM 7/22/2003]
[Modified by Boofers, 5:34 PM 7/22/2003]
[Modified by Boofers, 5:34 PM 7/22/2003]
07-22-2003, 07:23 PM
#9
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Re: How can I cure the odd misfire at idle? (Boofers)
Just wondering if u have point or hei ignition? My 74 did it real bad so i went with hei never ran better and it dropped 2 tenths off my 1/4 mile time
07-22-2003, 07:53 PM
#10
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Re: How can I cure the odd misfire at idle? (Boofers)
My 79 L-48 does the very same thing, a slight puff or pop from either pipe. it really is nothing and when it's in gear it can't even be felt. I wouldn't worry about it. :chevy
07-23-2003, 12:15 AM
#11
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Re: How can I cure the odd misfire at idle? (Boofers)
:rolleyes: First place I'd look is the #5 and #7 wires running along side each other. These two need to be spead out/separated and cross at 90degree angles if possible. :rolleyes: With the 18436572 firing order missfires are possible here.
Now I have to mention that my new (<30k mi.) Goodwrench motor had a low RPM/idle miss that I couldn't tune out. A brand new MSD6A and MSD distributor couldn't cure it either. :confused: Upon cam inspection during a cam swap discovered #4 exhuast lobe wiped nearly round. Whoever installed the motor for previous owner failed to break in the cam properly. :( This is fairly rare I would guess but depending how desperate you get - you could verify valve lift with a dial indicator on magnetic base. Remove the plugs first to turn the motor over by hand (Duh). :skep:
Good luck Boofers.
Now I have to mention that my new (<30k mi.) Goodwrench motor had a low RPM/idle miss that I couldn't tune out. A brand new MSD6A and MSD distributor couldn't cure it either. :confused: Upon cam inspection during a cam swap discovered #4 exhuast lobe wiped nearly round. Whoever installed the motor for previous owner failed to break in the cam properly. :( This is fairly rare I would guess but depending how desperate you get - you could verify valve lift with a dial indicator on magnetic base. Remove the plugs first to turn the motor over by hand (Duh). :skep:
Good luck Boofers.
