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Hard to start and low idle / misfire after a warm start...

  #1  
Old 06-23-2009, 02:34 PM
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Default Hard to start and low idle / misfire after a warm start...

I have an 02 F4i with 4,0xx miles on it, i just did an oil/filter change about 200 miles ago.

I bought it used in December with 2000 miles on it.

For the past few days (100~ miles?) it would occasionally have a hard time starting after the engine had warmed up (sitting in the sun or previously ran), and would kinda sputter around 1100rpm's (it normally starts and idles around 2000 till it gets warmed up and then drops to 1300-1500 i think). Sounds a lot like a misfire or dead cylinder.

If i give it a little rev (to 2000~2500~)rpms it will cough out the misfire and idle just like it normally does.

These recently started right when we started to hit 90+ temperatures and high humidity...

Just looking for some ideas on how to fix it. Going to pickup some injector cleaner etc and see if that helps.

Since the bike had been sitting it appeared when i bought it, i took apart the tank and pumps and looked them over made sure they worked properly and reassembled. Also has brand new air filter.

No performance modifications aside from K&N air filter and a cutoff pipe (performance decrease? ) Cutoff has a baffle i made to restore semi-stock backpressure levels and lower noise levels.

Recently dynoed with a near picture perfect power curve and 91hp (3000 miles~ with cutoff and no baffle)

the pipe and filter have been on the bike since 2500 miles ago, i have a hard time believing that all the sudden a bad a/f ratio is all the sudden going to cause a rough idle.

I'm making a custom exhaust right now, but when it starts rough, after a blip of the throttle it get a real rich smell and then a little puff and back to normal.

I think i may have a fouled plug and am going to replace all 4 plugs tonight. Already running some seafoam through the tank, though i doubt that a clogged injector is the culprit especially by the rich smell i get during the stumbling idle.

NOTE: ALL mods have been on the bike for at least 500 miles prior to this incident (baffle or no baffle)
NOTE: PC3 will be here tomorrow, maybe that will help...
 
  #2  
Old 06-23-2009, 06:47 PM
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Location: Lexington, NC
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did you put brand new gas in it when you took your tank off and fuel pump out?
 
  #3  
Old 06-23-2009, 09:25 PM
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yes, and that was done approx 2500 miles ago.
 
  #4  
Old 06-23-2009, 09:39 PM
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Location: Lexington, NC
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it sounds to me that you're probably on the right path with changing out your plugs

when you remove your plugs look at them and let us know if you were lean or rich
 
  #5  
Old 06-23-2009, 10:23 PM
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plugs appear to be good and read well, not as lean as i thought, actually a bit more rich than i thought.

couple looked to have a light amount of oil on them but i don't think anything to be concerned about, definately a veerry light amount of oil.
 
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