Cylinder Misfire but not Coil Packs or Plugs
#1
06-29-2017, 05:57 PM
Cylinder Misfire but not Coil Packs or Plugs
Hello Everyone,
Im new, so go easy on me!
My 2007 Fit Sport is throwing codes P0300 and P0302 for random misfires and misfires in cylinder #2 (the dreaded fit curse). Ive just replaced the coil packs with Hitachis (not the best, I know) and all of the spark plugs are gapped to spec, though they are at maximum.
No matter if I switch out coil packs and spark plugs, the misfire is always in cylinder #2, so I think that those two items can be ruled out. Where should I go from here?
Im sure that there is an answer in the forum that I am just not finding...probably multiple.
Im new, so go easy on me!
My 2007 Fit Sport is throwing codes P0300 and P0302 for random misfires and misfires in cylinder #2 (the dreaded fit curse). Ive just replaced the coil packs with Hitachis (not the best, I know) and all of the spark plugs are gapped to spec, though they are at maximum.
No matter if I switch out coil packs and spark plugs, the misfire is always in cylinder #2, so I think that those two items can be ruled out. Where should I go from here?
Im sure that there is an answer in the forum that I am just not finding...probably multiple.
#3
06-29-2017, 10:32 PM
If misfire stays on cylinder 2 with known good plug and coil,
--The coil connector may be damaged or dirty (with engine running wiggle wire next to connector, also take it off the coil and inspect wire terminals inside using flashlight)
-- the exhaust valve(s) might be tight in this particular cylinder (valve clearance adjustment required)
Need to know mileage and misfire pattern:
engine cold, hot, at idle or at acceleration?
misfire with cold engine goes away at acceleration or as engine warmed up - tight valve
misfire on hot engine with high ambient heat and a/c on--ignition coil
In rare instances e-bay or amazon coils might be counterfeit (copies of Hitachi-053 part which should be made in Japan and have blue boots and vent hole on the back)
Also visually inspect the shorting connector under air cleaner net to intake (under black rubber boot for extensive dirt or moisture!)
--The coil connector may be damaged or dirty (with engine running wiggle wire next to connector, also take it off the coil and inspect wire terminals inside using flashlight)
-- the exhaust valve(s) might be tight in this particular cylinder (valve clearance adjustment required)
Need to know mileage and misfire pattern:
engine cold, hot, at idle or at acceleration?
misfire with cold engine goes away at acceleration or as engine warmed up - tight valve
misfire on hot engine with high ambient heat and a/c on--ignition coil
In rare instances e-bay or amazon coils might be counterfeit (copies of Hitachi-053 part which should be made in Japan and have blue boots and vent hole on the back)
Also visually inspect the shorting connector under air cleaner net to intake (under black rubber boot for extensive dirt or moisture!)
#4
06-29-2017, 10:46 PM
Tyvm doc! I'll try those this weekend and post the results here.
The cylinder is a dead miss off idle in the mid rpm range. The car has 107,000 miles and is on its 3rd full set of coils. I just changed coils last weekend. I did not test the resistance of the old coils, so they may not have even been bad.
The cylinder is a dead miss off idle in the mid rpm range. The car has 107,000 miles and is on its 3rd full set of coils. I just changed coils last weekend. I did not test the resistance of the old coils, so they may not have even been bad.
#6
06-30-2017, 06:57 AM
Perhaps running compression test would be nice for cylinders 2 and 3, but injectors are not so easy to unplug.
If valves were never adjusted in this car its time to do it now
If valves were never adjusted in this car its time to do it now
#7
06-30-2017, 07:05 AM
Try reducing the gap
What mods have you done? What plugs are you using?
If you are N/A, and using the correct OEM plugs, try reducing the gap to 0.032" (or 0.8mm). I used that trick on my 2007 GD3 ever since I fried my first coilpack.
Better yet, here is what Ive been using since 2009 with great results. I went one step lower, using Denso IK22 Iridium Power Spark Plugs PN:5310. I then check the gap to make sure it is set down to at least 0.8mm (0.032"). I have set them as low as 0.7mm or 0.028".
I now have 332,500 miles on this Fit, and 2 of the coil packs are still original.
I've read that the larger the gap, the harder it is on the coil pack. The smaller gap requires less resources from the coil pack, therefore extending the life of the coil.
The trade off is that they say a larger gap gives a larger spark, and therefore better combustion. However, my thinking is that a reliable spark from a smaller gap is better than no spark from a larger gap.
Anyway, give this a try. Hopefully this will solve your problem, it did for me.
If you are N/A, and using the correct OEM plugs, try reducing the gap to 0.032" (or 0.8mm). I used that trick on my 2007 GD3 ever since I fried my first coilpack.
Better yet, here is what Ive been using since 2009 with great results. I went one step lower, using Denso IK22 Iridium Power Spark Plugs PN:5310. I then check the gap to make sure it is set down to at least 0.8mm (0.032"). I have set them as low as 0.7mm or 0.028".
I now have 332,500 miles on this Fit, and 2 of the coil packs are still original.
I've read that the larger the gap, the harder it is on the coil pack. The smaller gap requires less resources from the coil pack, therefore extending the life of the coil.
The trade off is that they say a larger gap gives a larger spark, and therefore better combustion. However, my thinking is that a reliable spark from a smaller gap is better than no spark from a larger gap.
Anyway, give this a try. Hopefully this will solve your problem, it did for me.
#8
06-30-2017, 10:35 AM
As you have probably deduced, I am by no means an expert mechanic.
My understanding is that if a cylinder has lost compression that the spark plug should be fuel fouled. Is this true?
I will end up doing a compression test anyway just so that I understand how it is done.
My understanding is that if a cylinder has lost compression that the spark plug should be fuel fouled. Is this true?
I will end up doing a compression test anyway just so that I understand how it is done.
#9
06-30-2017, 10:39 AM
What mods have you done? What plugs are you using?
If you are N/A, and using the correct OEM plugs, try reducing the gap to 0.032" (or 0.8mm). I used that trick on my 2007 GD3 ever since I fried my first coilpack.
Better yet, here is what Ive been using since 2009 with great results. I went one step lower, using Denso IK22 Iridium Power Spark Plugs PN:5310. I then check the gap to make sure it is set down to at least 0.8mm (0.032"). I have set them as low as 0.7mm or 0.028".
I now have 332,500 miles on this Fit, and 2 of the coil packs are still original.
I've read that the larger the gap, the harder it is on the coil pack. The smaller gap requires less resources from the coil pack, therefore extending the life of the coil.
The trade off is that they say a larger gap gives a larger spark, and therefore better combustion. However, my thinking is that a reliable spark from a smaller gap is better than no spark from a larger gap.
Anyway, give this a try. Hopefully this will solve your problem, it did for me.
If you are N/A, and using the correct OEM plugs, try reducing the gap to 0.032" (or 0.8mm). I used that trick on my 2007 GD3 ever since I fried my first coilpack.
Better yet, here is what Ive been using since 2009 with great results. I went one step lower, using Denso IK22 Iridium Power Spark Plugs PN:5310. I then check the gap to make sure it is set down to at least 0.8mm (0.032"). I have set them as low as 0.7mm or 0.028".
I now have 332,500 miles on this Fit, and 2 of the coil packs are still original.
I've read that the larger the gap, the harder it is on the coil pack. The smaller gap requires less resources from the coil pack, therefore extending the life of the coil.
The trade off is that they say a larger gap gives a larger spark, and therefore better combustion. However, my thinking is that a reliable spark from a smaller gap is better than no spark from a larger gap.
Anyway, give this a try. Hopefully this will solve your problem, it did for me.
Im definitely going to reduce the gap. I dont need high performance anyway...just a reliable ride to work.
Because the miss is always in #2, no matter which coil or plug, I feel that there is something else wrong besides gapping. Ill follow everyones suggestions and get back with the results.
I very much appreciate everyones help!
#10
06-30-2017, 11:00 AM
If cylinder has low compression, the plug will be dark (looking "too cold")
Reducing gap will cause hiccups during sudden acceleration and high rpm upshift. This may be unacceptable for city driving in populated areas (increase risk of road rage from driver behind, which is OK if you are driving vintage Chevy 350 truck
)
Reducing gap will cause hiccups during sudden acceleration and high rpm upshift. This may be unacceptable for city driving in populated areas (increase risk of road rage from driver behind, which is OK if you are driving vintage Chevy 350 truck
)
#11
06-30-2017, 11:04 AM
#12
06-30-2017, 03:30 PM
this is for static compression test (although it is better to disable the fuel pump to prevent spraying gas into cylinders . Dynamic or running compression test is done with engine running (idling)
#14
07-01-2017, 02:08 AM
Compression tester will not show what a leakdown does. Lots of issues wont show on a compression test. especially a lightly blown head gasket. Especially with the MLS gaskets that are stock on the fit. They can seal cold and bleed under running conditions. The compression test will reveal a blown piston, burnt valve of course..
Once I started using a leakdown tester,, I'll likely never bother with a comp tester again. Takes the same time and I do it with a pancake compressor. I ended up fighting mine with a blown gasket for weeks when if I'd just a thought through it and done the leakdown there it would have been.
But,,
1. Clean the throttle body.
2. Adjust the valves needs done every 60 to 80 k (Really it does..
)
3. Factory stock plugs, they should be gaped correctly out of the box.
4. Check all your grounds (Battery neg to every part of the motor with electrics attached.)
5. Test the battery, it seriously messes with the fits ECU if the battery is getting tired, doesn't take much at all..
Cheers man, good luck!
Once I started using a leakdown tester,, I'll likely never bother with a comp tester again. Takes the same time and I do it with a pancake compressor. I ended up fighting mine with a blown gasket for weeks when if I'd just a thought through it and done the leakdown there it would have been.
But,,
1. Clean the throttle body.
2. Adjust the valves needs done every 60 to 80 k (Really it does..
)3. Factory stock plugs, they should be gaped correctly out of the box.
4. Check all your grounds (Battery neg to every part of the motor with electrics attached.)
5. Test the battery, it seriously messes with the fits ECU if the battery is getting tired, doesn't take much at all..
Cheers man, good luck!
#15
07-02-2017, 09:27 PM
An update:
Today I gapped the valves and did a dry/wet compression test. Should have done the compression test first lol.
Many of the valves were improperly gapped, so now that's better. However the compression test did not make my day any better. The dry test read 195/90/185/190, indicating an issue with the #2 cylinder as expected. On the wet test the #2 cylinder read 195. My understanding is that is indicative of a valve ring failure and an expensive valve job in my future.
There was also about a tablespoon of oil where the air intake connects to the throttle body.
Deciding if a valve job is going to be worth it or if another car is in my future. Anyone know the going rate for a DIY valve job including someone machining the head?
Today I gapped the valves and did a dry/wet compression test. Should have done the compression test first lol.
Many of the valves were improperly gapped, so now that's better. However the compression test did not make my day any better. The dry test read 195/90/185/190, indicating an issue with the #2 cylinder as expected. On the wet test the #2 cylinder read 195. My understanding is that is indicative of a valve ring failure and an expensive valve job in my future.
There was also about a tablespoon of oil where the air intake connects to the throttle body.
Deciding if a valve job is going to be worth it or if another car is in my future. Anyone know the going rate for a DIY valve job including someone machining the head?
#17
07-02-2017, 11:24 PM
I would try to use small electronic "borescope" or plumbing camera to inspect cylinder walls for scoring; oil in intake indicates high blow by.
How is the oil consumption and what is the history of oil changes?
How is the oil consumption and what is the history of oil changes?
#18
07-03-2017, 01:49 AM
There was also a slight hesitation before accelerating but either the valve adjust or throttle body clean took care of that.
#19
07-03-2017, 08:52 AM
If inspection with camera (one from Home depot is shown but can be cheaper) http://www.homedepot.com/catalog/pro...3c2a0_1000.jpg
does not revel any vertical lines on #2 cylinder wall the piston ring can be stuck to piston groove because of infrequent use. The old school (last chance ) method is to administer one of each teaspoons of denatured alcohol and kerosene into the problem cylinder (engine is warm to touch, piston between the dead centers) and let it sit overnight without spark plug (cover the hole). Next morning reinstall the plug, start it up let it idle for 2 minutes, then stab the throttle few times. drive it for a day and re-check compression. The oil may have to be changed soon after
does not revel any vertical lines on #2 cylinder wall the piston ring can be stuck to piston groove because of infrequent use. The old school (last chance ) method is to administer one of each teaspoons of denatured alcohol and kerosene into the problem cylinder (engine is warm to touch, piston between the dead centers) and let it sit overnight without spark plug (cover the hole). Next morning reinstall the plug, start it up let it idle for 2 minutes, then stab the throttle few times. drive it for a day and re-check compression. The oil may have to be changed soon after
#20
07-10-2017, 04:59 PM
Hello Everyone,
Im new, so go easy on me!
My 2007 Fit Sport is throwing codes P0300 and P0302 for random misfires and misfires in cylinder #2 (the dreaded fit curse). Ive just replaced the coil packs with Hitachis (not the best, I know) and all of the spark plugs are gapped to spec, though they are at maximum.
No matter if I switch out coil packs and spark plugs, the misfire is always in cylinder #2, so I think that those two items can be ruled out. Where should I go from here?
Im sure that there is an answer in the forum that I am just not finding...probably multiple.
Im new, so go easy on me!
My 2007 Fit Sport is throwing codes P0300 and P0302 for random misfires and misfires in cylinder #2 (the dreaded fit curse). Ive just replaced the coil packs with Hitachis (not the best, I know) and all of the spark plugs are gapped to spec, though they are at maximum.
No matter if I switch out coil packs and spark plugs, the misfire is always in cylinder #2, so I think that those two items can be ruled out. Where should I go from here?
Im sure that there is an answer in the forum that I am just not finding...probably multiple.
have the same problem, please keep us posted