Misfire
02-18-2008, 01:04 AM
#1
Melting Slicks
Thread Starter
Misfire
Can anyone tell me what a misfire sounds like/acts like?
I've tried looking up videos from Youtube and similar places but can't really find a good video to hear what a misfire really sounds like. Plus, from what I read, it can range from a slight vibration to an audible noise.
I've tried looking up videos from Youtube and similar places but can't really find a good video to hear what a misfire really sounds like. Plus, from what I read, it can range from a slight vibration to an audible noise.
02-18-2008, 06:45 AM
#2
Safety Car
You already said it .... it can range from a slight vibration to an audible noise ..... depends on how many cylinders are misfiring, and how often. The PCM will post a P0300 DTC when it detects a misfire .... have you checked for that ???
02-18-2008, 07:14 AM
#3
They happen all the time and you never know it. There are an amount of misfires that are acceptable (and you can see them on a scanner). When they pass this threshold it's logged in the ECM, 2 in a run cycle and the CEL light is set. P0300 for random misfire and/or P030X where X is the cylinder misfiring.
Last edited by dougbfresh; 02-18-2008 at 03:08 PM.
02-18-2008, 10:56 AM
#4
Melting Slicks
Thread Starter
Hmm...
You guys notice any misfires in my video?
http://www.youtube.com/watch?v=gMIoB4LCNA8
There is a sharp POP! when I let off the gas, but otherwise it's ok I suppose.
...just trying to narrow down a ticking noise I've been hearing for a while on what it could be.
You guys notice any misfires in my video?
http://www.youtube.com/watch?v=gMIoB4LCNA8
There is a sharp POP! when I let off the gas, but otherwise it's ok I suppose.
...just trying to narrow down a ticking noise I've been hearing for a while on what it could be.
02-18-2008, 12:02 PM
#6
Le Mans Master
Hey quickshift what are the codes your PCM giving? As doug and Black where saying start with the code and then go from there.
Last edited by Brandon619; 02-18-2008 at 09:19 PM.
02-18-2008, 08:56 PM
#7
Melting Slicks
Thread Starter
02-19-2008, 02:18 PM
#8
Tech Contributor
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
Using the C5 Diagnostics, the P-0030 DTC will only post under an excessive misfire situation. During that misfire situation, the Check Engine Light (CEL) will FLASH during the event.
To see what a TRUE misfire is, just unhook one spark plug wire from the spark plug and take her for a spin around the block!
Yep, that will be a misfire and you will see the flashing CEL and the set P-0300 DTC. The DTC will only stay set in memory until you turn the ignition OFF. Once it is off,,,,it resets it self until the next misfire event. It wont hurt anything for a short experiment. Once the car cools off, reinstall the wire.
The popping in the exhaust is normal on our engines!
Bill
To see what a TRUE misfire is, just unhook one spark plug wire from the spark plug and take her for a spin around the block!
Yep, that will be a misfire and you will see the flashing CEL and the set P-0300 DTC. The DTC will only stay set in memory until you turn the ignition OFF. Once it is off,,,,it resets it self until the next misfire event. It wont hurt anything for a short experiment. Once the car cools off, reinstall the wire.
The popping in the exhaust is normal on our engines!
Bill
