Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Cylinder #2 Misfire & check engine light blinking just when idling


  • Please log in to reply
32 replies to this topic

#26 lmdew

lmdew

    _______

  • Members
  • 3,054 posts
  • Colorado Springs

Posted 27 October 2013 - 04:47 PM

I thought you had a dollar bill get sucked back into the exhaust tail pipe.  If so you have a bent valve that is not closing all the way.  You may get a little power out of it, but not much.

 

Used 2.2 from a Self Serve yard $200.  



#27 Fairtax4me

Fairtax4me

    Su bah roo'n

  • Gold Subscribers
  • 9,085 posts
  • Charlottesburg, VA

Posted 27 October 2013 - 07:39 PM

The blinking light has nothing to do with the O2 sensor.
ECU senses misfires by reading changes in crankshaft speed. Every time there is a misfire there is a change in crankshaft speed because the lack of power from that cylinder causes the crank to slow down slightly on the next cylinders compression stroke.
The ECU counts each percieved misfire (it doesn't always pick them up) And keeps track of how often the misfire occurs, then compares that against engine revolutions.
When a misfire occurs a certain number of times, something like 10 times in 1,000 revolutions, (i dont recall the exact number) the ECU sets a code and turns on the CEL. But if that misfire occurs 40 times in 200 (two hundred) revolutions the ECU sets a code and blinks the CEL to let you know there is a major problem which can quickly turn your cats to glowing red orbs.

With a burned valve there is a loss of compression in the cylinder at low engine speed. The engine doesn't spin fast enough for the compression to build to an adequate level in order for there to be combustion. Also add to that, at idle the throttle plate is closed so there is less air available to the engine. When less air is available there is lower compression. These two factors joined together will cause a misfire at idle speed.
When the throttle is opened you get more air, and the engine speed increases, which means there is less time for compression to escape through the burned valve. Now there is enough compression for combustion, though it will not be ideal, the crankshaft speed will not be effected as much as it would be with the misfire.

So at idle, the ECU sees more misfires happening because of the lower compression, and the misfire occurs often enough to trigger the blinking CEL.
When engine speed is raised the misfires do not occur as often, the CEL stops blinking, but remains on partly because of the misfire count, but also because when a misfire occurs the CEL remains on until a certain number of engine revolutions has occurred withOUT a misfire.

#28 Gecko1650

Gecko1650

    Newbie

  • Members
  • Pip
  • 9 posts
  • Jackson, Wyoming

Posted 27 October 2013 - 09:52 PM

Wow, that was really helpful. That makes a lot of sense. Thanks for the write up



#29 ivans imports

ivans imports

    1000+ Super USER!

  • Members
  • 2,954 posts
  • lumby bc canada

Posted 01 November 2013 - 09:40 AM

have piles of cly heads if need one



#30 Wazer

Wazer

    Newbie

  • Members
  • Pip
  • 3 posts
  • Lexington, NC

Posted 09 November 2013 - 09:06 AM

I have a '06 Baja Turbo with the same issue. Replaced spark plug , coil, fuel injector! NOTHING!!!!! Mine idols like a charm, then when I put it in drive that's when it does it. I rev it up in neutral, it gets worse. Put it in park I can hear a pinging notice but idols good. If I drive it, runs like a top!! Somebody help.

#31 Wazer

Wazer

    Newbie

  • Members
  • Pip
  • 3 posts
  • Lexington, NC

Posted 09 November 2013 - 09:07 AM

I have a '06 Baja Turbo with the same issue. Replaced spark plug , coil, fuel injector! NOTHING!!!!! Mine idols like a charm, then when I put it in drive that's when it does it. I rev it up in neutral, it gets worse. Put it in park I can hear a pinging notice but idols good. If I drive it, runs like a top!! Somebody help.

#32 Wazer

Wazer

    Newbie

  • Members
  • Pip
  • 3 posts
  • Lexington, NC

Posted 09 November 2013 - 09:12 AM

Also had a compression test. Held consistently at 130,give or take. I think specs are 158>.?????

#33 ivans imports

ivans imports

    1000+ Super USER!

  • Members
  • 2,954 posts
  • lumby bc canada

Posted 10 November 2013 - 11:19 AM

Feul pump low out put pinging is no feul getting to engine check for pluged intank pump screen






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users