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Misfire on Cylinder #4

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Old 11-24-2018, 09:45 PM
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Default Misfire on Cylinder #4

So I've been having some issues with my motor for atleast 2 years now and still can't seem to figure out what's wrong.

Quick back story.

Swapped out my perfectly fine running F20 and swapped in a freshly built F24 motor. That motor overheated and the F20 was swapped back in. I now have completed the 2.4L motor and it's i It's currently in the car. I'm running the CNC Speedshop kit with Wiseco pistons and the head has just been refreshed with some ap2 goodies. Anyways, I've started the new motor and am getting a misfire on cylinder #4. This has happened when I swapped my my previous motor back in as well(F20).

Problem: 2 separate motors misfiring on cylinder #4 after tons of troubleshooting. Misfire is almost always present on or off throttle.

List of diagnosis:
- IAT sensor position
- Multiple TPS sensors
- MAP sensor
- fuel Injectors
- pigtails for the Injectors
- Brand new OEM engine harness
- Brand new OEM coil packs
- new spark plugs
- multiple tunes
- swapped known working coil packs
- leak down(f20c)

Things I'm going to check:
- Leak down
- compression test
- check ecu pins(ecu side)
- try a friend's Kpro unit
- send my computer back to hondata to be checked

If anyone has had this haopha to them let me know what it was please! Also, if there's something I might've overlooked, let me know
Old 11-25-2018, 04:49 AM
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So what exactly have you done to try and narrow it down?
Old 11-25-2018, 02:38 PM
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Originally Posted by summitrider2012
So what exactly have you done to try and narrow it down?
List of diagnosis:
- IAT sensor position
- Multiple TPS sensors
- MAP sensor
- fuel Injectors
- pigtails for the Injectors
- Brand new OEM engine harness
- Brand new OEM coil packs
- new spark plugs
- multiple tunes
- swapped known working coil packs
- leak down(f20c)
Old 11-25-2018, 11:48 PM
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Checked fuel rail fpr & fuel preassure
Old 11-26-2018, 01:40 AM
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Originally Posted by noodels
Checked fuel rail fpr & fuel preassure
Anyway to check that without a fuel pressure gauge? I'll add that to the list
Old 11-26-2018, 03:28 AM
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Originally Posted by cheddaboy
List of diagnosis:
- IAT sensor position
- Multiple TPS sensors
- MAP sensor
- fuel Injectors
- pigtails for the Injectors
- Brand new OEM engine harness
- Brand new OEM coil packs
- new spark plugs
- multiple tunes
- swapped known working coil packs
- leak down(f20c)

yes but but what exactly did you do? Like replace just the tps or the whole throttle body? Did you swap around the fuel injectors before you replaced them or just replace them? Did you check resistance from the pigtails you installed to the ecu/power? Stuff like that is what I was wondering.
Old 11-27-2018, 01:44 PM
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Ohh sorry about that lol

- swapped IAT sensor position from manifold to after cooler about 6" before tb
- tried 3-4 TPS sensors all calibrated(both OEM and aftermarket)
- tried 2 separate 3 bar MAP sensors and tested voltage at the connector
- swapped injectors back and forth between cylinders with 2 separate sets. Also trued hardwiring the to the harness.
- tried old and new pigtails for the Injectors
- Brand new OEM engine harness
- Brand new OEM coil packs(tried two used sets as well
- new spark plugs
- multiple tunes
- swapped known working coil packs(useda dummy sparkplug to see if the coil pack was working
- leak down(f20c)

Also tried 2 different tb's

when checking resistance at the ecu pigtails, what should it read?
Old 11-27-2018, 01:56 PM
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Originally Posted by cheddaboy
Anyway to check that without a fuel pressure gauge? I'll add that to the list
Nope.
Old 11-27-2018, 02:08 PM
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Suggest buy a kit for testing low and high preassure ,then can test for voltage values as needed
Old 11-28-2018, 09:50 AM
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Originally Posted by noodels
Suggest buy a kit for testing low and high preassure ,then can test for voltage values as needed
Low and high pressure in the cylinders?? Like a compression and leakdown test?


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