KLX 250 EFI (2009): 4k rpm idle when hot

Old Oct 13, 2021 | 05:43 AM
  #1  
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Default KLX 250 EFI (2009): 4k rpm idle when hot

Hey.

My 2009 EFI model works perfectly, unless hot. What I mean by "hot" is generally a normal working temperature, after some 15-20 kilometers done. Then - the engine idles at roughly 4krpm. The throttle cable slack is correct (or even too loose), the throttle screw completely out (screwed backwards to the physical stop). Restarting the bike does not change anything. No warning lamps or any other visible symptoms of any problem. Except for the idle, bike runs well.

Current bike setup:
OEM top-end, OEM exhaust, KDX snorkel, O2 sensor bypass, clutch mode done, MCM done, iridium plug. EJK currently disconnected, as it was my first bet; disconnecting the EJK did not help.

What should be my next steps?

Thanks!
y.
 

Last edited by yahoo666; Oct 13, 2021 at 07:18 AM.
Old Oct 15, 2021 | 12:37 AM
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I am still working to figure out how the fuel injection works on these bikes, but here are some things to consider (you may need a diagnostic tool to help figure it out).
Does the bike have the fuel injection light on, if so see if you can find a manual online or find the procedure on how to read the codes? I found a manual online a week or so ago but did not save the link. If I find it again I will post it up. From sifting through here are some things to consider.
An air leak after the throttle blade. The crankcase is vented to the inlet, so a loose oil cap could cause high idle
Idle air control device, Kawasaki calls it a sub throttle I believe.
These bikes have an inlet air pressure sensor (traditionally what I would call a map sensor), may be reading incorrectly - not sure this could account for the high idle though.
The pressure sensor is used at low throttle angles/position. The bike uses alpha-n at high throttle angles, which means the main fueling is programmed based on rpm and throttle position.
Flakey rpm signal.
Let us know what you find out.
 
Old Jan 17, 2022 | 01:06 PM
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Where did you get a FI 2009? Mine cas a carb.
 
Old Jan 17, 2022 | 01:27 PM
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Originally Posted by bmart
Where did you get a FI 2009? Mine cas a carb.
Europe perhaps

I have a 2009 EFI as well in Denmark
 
Old Jan 18, 2022 | 12:43 AM
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I'm not familiar with the older efi models, but unless it uses a drive-by-wire throttle it will have a direct connection from the throttle to the throttle body using a standard throttle cable.
I would suspect that it also uses an idle air bypass solenoid to control idle speed. If the tps is not adjusted properly the ecm may not know that the throttle is closed and is doing some funky things with the iac solenoid. just a thought
 
Old Jan 18, 2022 | 01:17 AM
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Originally Posted by GBAUTO
I'm not familiar with the older efi models, but unless it uses a drive-by-wire throttle it will have a direct connection from the throttle to the throttle body using a standard throttle cable.
I would suspect that it also uses an idle air bypass solenoid to control idle speed. If the tps is not adjusted properly the ecm may not know that the throttle is closed and is doing some funky things with the iac solenoid. just a thought
I originally thought the same, but these bikes have a secondary throttle butterfly valve that is servo controlled by the ecu. So as best I can tell there is a manual idle are valve that can be manually adjusted and the secondary throttle, these are the main means of idle speed control. The ecu may also use timing, but not sure how much influence that can have. Problem is nobody seems to have cracked the ecu on these bikes, at least no one willing to share.
 
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