Misfire Blues - Honda-Tech


Misfire Blues

Reply
 
 
 
Thread Tools Search this Thread
Old 07-27-2016, 12:01 PM   #1
Honda-Tech Member
Thread Starter
 
Join Date: Jul 2016
Posts: 3
Default Misfire Blues

It's an '07 with 150k miles on it. It started misfiring ever so slightly a couple of months ago. Finally it got bad enough to start setting random misfire codes. So like any reasonable person I changed the plugs and coil packs. I thought I fixed it for about 5 minutes until it started to misfire again. It also doesn't want to accelerate. Any ideas? I'm lost... Thanks.
Fitfits is offline   Reply With Quote
Old 07-28-2016, 09:41 AM   #2
Honda-Tech Member
 
Join Date: May 2009
Location: San Lorenzo Valley, Santa Cruz Mountains, CA
Posts: 351
Default Re: Misfire Blues

Adjust the valve clearance and your problems will go away. Valve clearance adjustment is part of normal maintenance for all Fits.
manxman is offline   Reply With Quote
Old 08-05-2016, 05:02 PM   #3
Honda-Tech Member
Thread Starter
 
Join Date: Jul 2016
Posts: 3
Default Re: Misfire Blues

I don't understand...how could misadjusted valves cause random misfires??
Fitfits is offline   Reply With Quote
Old 08-06-2016, 01:15 PM   #4
Honda-Tech Member
 
Join Date: May 2009
Location: San Lorenzo Valley, Santa Cruz Mountains, CA
Posts: 351
Default Re: Misfire Blues

Obviously, in the 150 K miles on your engine, the valve clearance has never been adjusted. That maintenance procedure should have been done a very long time ago,and you are lucky that the engine runs at all. Over time and miles, the exhaust valves tighten up and don't allow enough exhaust out of the cylinders for efficient combustion of each new cycle of each cylinder. At the same time, the intake valve adjustment becomes looser which further upsets the balance of fuel/air mixture in the cylinder. Miss-fires occur when there is an imbalance of fuel and air for each combustion stroke of the engine. Too much fuel, with too much old exhaust from the previous cycle, and not enough air, the spark plug won't ignite the charge in the cylinder, and/or the combustion is incomplete and can't deliver the usual amount of force to keep the engine running smoothly.

But don't take my word for it- see a mechanic and get the job done. You are only about 100 K late.
manxman is offline   Reply With Quote
Old 08-07-2016, 09:16 PM   #5
Honda-Tech Member
 
claymore's Avatar
 
Join Date: Feb 2006
Location: Super Troll slayer valley
Posts: 777
Default Re: Misfire Blues

When the exhaust valve beats itself into the valve seat it causes the tip of the valve to be physically higher out of the head decreasing the amount of clearance between the valve tip and the cam follower. This causes the exhaust valve to open FURTHER not less. The result is a lean condition which results in a misfire. The symptoms of a valve clearance issue is rough idle, stalling and misfire. With that many miles it surely needs an adjustment.
claymore is offline   Reply With Quote
Old 08-08-2016, 06:29 AM   #6
Honda-Tech Member
Thread Starter
 
Join Date: Jul 2016
Posts: 3
Default Re: Misfire Blues

I understand that the valves are way overdue for adjustment. However, if that's what's causing the problem wouldn't the misfire be constant rather than random and intermittent?
Fitfits is offline   Reply With Quote
Old 08-08-2016, 11:25 PM   #7
Honda-Tech Member
 
claymore's Avatar
 
Join Date: Feb 2006
Location: Super Troll slayer valley
Posts: 777
Default Re: Misfire Blues

Nope this is a common problem and the misfire is intermittent depending on load.
claymore is offline   Reply With Quote
Old 08-12-2016, 07:12 PM   #8
Honda-Tech Member
 
Join Date: Aug 2013
Posts: 195
Default Re: Misfire Blues

Have you checked the car while running with a scan tool that shows live data, there should be live data stream of your engine running that can help you diagnose it. What codes are you getting and is it a misfire on one or multiple cylinders. Did you replace with genuine Honda OEM coil packs? Also did you check the wiring from coils to PCM, if you did check pcm output to coils? I'm pretty sure it should lead you in the right direction .
m90polk1 is offline   Reply With Quote
Old 08-12-2016, 09:02 PM   #9
Honda-Tech Member
 
claymore's Avatar
 
Join Date: Feb 2006
Location: Super Troll slayer valley
Posts: 777
Default Re: Misfire Blues

LOL ^^^^^ you haven't been around Fits much right. This is a common Fit problem which can be fixed by adjusting the valve clearances. With that many miles and never having been done it surely needs it. My own needed adjustment after only 25,000 and he has 100,000 more miles than that.
claymore is offline   Reply With Quote
Old 08-13-2016, 10:25 AM   #10
Honda-Tech Member
 
Join Date: Aug 2013
Posts: 195
Default Re: Misfire Blues

But wouldn't you have valve tapping noise coming from the the head because of clearance issues?
m90polk1 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
2000 civic Si misfiring swain2894 Honda Civic / Del Sol (1992 - 2000) 19 04-27-2014 01:07 AM
Misfire with lots of codes, please help VIPERBLUELX Honda Civic (2001 - 2005) 7 09-18-2007 03:04 PM
Please Help, Engine Misfire! JDM5075 Acura Integra 2 04-03-2007 10:09 AM
misfire Griff Honda Prelude 5 01-16-2007 10:27 PM
97 B18c1 Horrbile Misfire Nsane Acura Integra 1 06-02-2006 07:04 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -8. The time now is 03:34 PM.