cylinder #6 misfiring
#1
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cylinder #6 misfiring
so i was on my way home today (150 mile drive) and when i go to pull out of the parking lot i noticed a slugish feel like if i was trying to take off in third gear... so i'm pissed because i just rebuilt the tranny and replaced the clutch... anywho get on the road and when rpm's go above 2k it seems to kick into gear lol... i stop off at my cousins house (it's on the way home) he scans it get a o2 sensor dtc for too much voltage which is bull because i just replaced these most likely it touched the collector and grounded itself... and pull up running data and cylinder 6 is misfiring
so what to do i'm still over 100 miles from home so i drive it my cousin said i'd get bad mpg due to the misfire but that should be the extent of the damage so i drive car feels normal i got home took out #6 plug it looks fine no cracks in the porcelain??? (i'm running ngk tr 6's) and it's intact... so i remove #6 plug and wire and exchange it for #2 to see if the ses light would go away for the misfiring... hook the battery back up ses light still on
so i've been looking on here (SEARCH) and have come up with if it is a bad plug or wire it should be misfiring on #2 now...
it could be a bad coil (not likely on ls1's)
WORST ONE I READ: bent pushrod (i have chromoly ones from comp cams) or bent valve...
i don't have a scanner and won't get to find out till tomorrow after school so if anybody else has any info it would be greatly appreciated, as i am literally shattin a brick... yeah i know if you wanna play you gotta pay but i just payed for the tranny and clutch so it would be great for the car to be working properly for a while...
*end rant*
so what to do i'm still over 100 miles from home so i drive it my cousin said i'd get bad mpg due to the misfire but that should be the extent of the damage so i drive car feels normal i got home took out #6 plug it looks fine no cracks in the porcelain??? (i'm running ngk tr 6's) and it's intact... so i remove #6 plug and wire and exchange it for #2 to see if the ses light would go away for the misfiring... hook the battery back up ses light still on
so i've been looking on here (SEARCH) and have come up with if it is a bad plug or wire it should be misfiring on #2 now...
it could be a bad coil (not likely on ls1's)
WORST ONE I READ: bent pushrod (i have chromoly ones from comp cams) or bent valve...
i don't have a scanner and won't get to find out till tomorrow after school so if anybody else has any info it would be greatly appreciated, as i am literally shattin a brick... yeah i know if you wanna play you gotta pay but i just payed for the tranny and clutch so it would be great for the car to be working properly for a while...
*end rant*
#3
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yeah i don't have any spark plugs laying around or i would have checked for spark... i didn't want to ruing something i don't have a replacement for... (worried about grounding the plug and it braking somehow lol... tomorrow i'm going to check it out (knock on wood) hopefully it's just a plug... i'm going to start with cheapest to most expensive lol that way hopefully it's the cheapest...
here's the order i'm going to do:
spark- that way if there is none i'll check the plug as that would be the cheapest (hopefully problem is here lol) then i'll check wire, then coil pack,
fuel- injector for #6
and finally hopefully resolution is found back in step one: compression test
what do you guys think? any other help opinions welcome
here's the order i'm going to do:
spark- that way if there is none i'll check the plug as that would be the cheapest (hopefully problem is here lol) then i'll check wire, then coil pack,
fuel- injector for #6
and finally hopefully resolution is found back in step one: compression test
what do you guys think? any other help opinions welcome
#4
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i agree with 87silverbullet.stick to the basics when you dont have scan tools.I dont really know how your car is running but i will give you examples that you can compare to your car . a fuel problem would most likely cause multiple cylinders to misfire. it will cause a running rough, sluggish, lack of power condition.if you have an intermittent misfire on just one cylinder you will almost only feel it under load. which is like when going up hill or low speed in a high gear.it will also get worse as the vehicle gets warmer. compression problems in one cylinder like a burnt valve or a bent pushrod, depending how severe the problem is,on a v8 is mostly felt more at idle.but when running you get a back fire because the valve is not fully opening and pressure builds up more than normal. i dont know what add ons you have or mileage but if mileage is low and you have no major internal work done i will rule out compression. coil pack issues usually throw codes also.so if you have no ignition codes i would also rule out the coil pack. i would check to see if your injector is hanging open in that cylinder.quick check, pull up the fuel rail turn the key on (dont crank ) and see if that injector is spraying fuel. swapping plugs and wires from cylinder to cylinder is a good test but only if your able to monitor live data. if you are able to view live data, drive your car with the scanner and see if the misfire moved.
#5
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You can check spark without pulling the plug just pull the wire and it will spark to the closest path to ground. You can find the root of this problem without a scan tool. If it is a fuel problem such as a bad injector that is not firing just swap an injector with another one and then pull the injector wire off and see if the engine idle speed changes. When the idle speed doesn't change then that is your culprit on that cylinder.
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#8
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***update***
*** UPDATE ***
so i worked on the car today... turns out it wasn't just cylinder 6 misfiring it was all of them it's just six climbed faster than the rest... spark was present wire was fine... pulled the injector and appereantly it's working because as soon as you pull it you can hear that piston drop... did a compression test on that cylinder needle went up to 125-130 psi?kpsi? what's the spec for this if anyone knows??? seems to be normal for a car with 95,000 miles... so ruled bent valve out because i'm sure the pressure wouldn't go up that high if the valve was f/d up... replaced coil pack from 6 with 1 misfires started to climb higher on 1 but all were still misfiring... (maybe coil pack isn't working as great as other) did a crank relearn... eureka car idled better and just sounded better... went for a test drive drove for about ten minutes and it was fine... parked and sat for about 5 minutes and went to take off again felt like i was trying to take off in third gear rolls ten-fifteen feet and it's like all of a sudden it realizes i'm in first gear and sees the throttle is partly in life comes back and it rips down the street odd much??? it's an m6 by the way... it's just at take off right now that it does this (knock on wood, fingers crossed, all that superstition stuff) no more misfires after crank relearn ses light was also on for p0152 high voltage to bank 2... which happens when the car runs rich... anyways when i was looking at the data on the o2 sensors they jump from 1xx-9xx and fluctuate is that normal??? as the mechanic that was helping me said that's not good... but they both fluctuate like that??? any help would be great as i don't wanna go out and dump 120 odd bucks if they are good
thank you
cesar
so i worked on the car today... turns out it wasn't just cylinder 6 misfiring it was all of them it's just six climbed faster than the rest... spark was present wire was fine... pulled the injector and appereantly it's working because as soon as you pull it you can hear that piston drop... did a compression test on that cylinder needle went up to 125-130 psi?kpsi? what's the spec for this if anyone knows??? seems to be normal for a car with 95,000 miles... so ruled bent valve out because i'm sure the pressure wouldn't go up that high if the valve was f/d up... replaced coil pack from 6 with 1 misfires started to climb higher on 1 but all were still misfiring... (maybe coil pack isn't working as great as other) did a crank relearn... eureka car idled better and just sounded better... went for a test drive drove for about ten minutes and it was fine... parked and sat for about 5 minutes and went to take off again felt like i was trying to take off in third gear rolls ten-fifteen feet and it's like all of a sudden it realizes i'm in first gear and sees the throttle is partly in life comes back and it rips down the street odd much??? it's an m6 by the way... it's just at take off right now that it does this (knock on wood, fingers crossed, all that superstition stuff) no more misfires after crank relearn ses light was also on for p0152 high voltage to bank 2... which happens when the car runs rich... anyways when i was looking at the data on the o2 sensors they jump from 1xx-9xx and fluctuate is that normal??? as the mechanic that was helping me said that's not good... but they both fluctuate like that??? any help would be great as i don't wanna go out and dump 120 odd bucks if they are good
thank you
cesar
Last edited by beezer1519; 12-02-2008 at 01:16 AM.
#10
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check your oxygen sensors for a bad connection or frayed wires its possible its just bad o2s though i had the same thing on my car just dumping fuel into the one bank from a shorted o2 sensor