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Idle lean condition

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Old Jan 13, 2005 | 01:00 AM
  #21  
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Lowered the MAF table a bit and it seems to have helped a lot. When I come to a stop it starts to..what seems like it is going into a surge cycle, but then very quickly recovers and winds down smoothly.

Now there is something weird going on with the fuel...
My LTFT's during steady cruise always seem to work their way to -12
Its as if there is something programmed in the computer to eventually adjust the fuel trims to -12. I have scaled IFR up, VE down, and MAF down. And while this -12 is showing, the wideband shows slightly lean for some reason
Like 14's for a little....then 15's and some occassional 16's, but mostly low 15's to low 16's. With -12 LTFT????????????????

WTF??????? Is the wideband lying? I doubt it.
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Old Jan 13, 2005 | 01:05 AM
  #22  
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you need to find the vacume leak, or air leak in the header system, then you can tune it.
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Old Jan 13, 2005 | 05:33 PM
  #23  
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Found a very small leak in the valve cover. I had to get spacers for the rockers and I went with Yella Terra's which are cast, not machined so they are not a perfect fit, but they are close.

Could this be what has been causing the issue? I found it because I lifted the car this morning and saw oil all over the headers and beyond...

I fixed it up today and just as an extra safety I used some silicon gasket maker stuff to add a little extra seal to everything.

I am currently waiting overnight for the gasket stuff to fully dry. Not sure if I really need to but it says fully cured in 12-24
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Old Jan 13, 2005 | 05:35 PM
  #24  
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a leaking valve cover wont be the leak causing you to be lean, but your getting closer. jes
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Old Jan 13, 2005 | 06:44 PM
  #25  
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You could try this old red neck trick -
Start the car, spray ether around the intake and any vacuum lines while it's running (Do not spray it into the intake). The rpms will pick up when the vacuum leak pulls the ether in. It will be tough to do in the back of the intake, but you may find it this way.
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Old Jan 13, 2005 | 07:32 PM
  #26  
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Originally Posted by itchygomey98
You could try this old red neck trick -
Start the car, spray ether around the intake and any vacuum lines while it's running (Do not spray it into the intake). The rpms will pick up when the vacuum leak pulls the ether in. It will be tough to do in the back of the intake, but you may find it this way.
Yeah tried that a few days ago...nothing responded....
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Old Jan 13, 2005 | 09:44 PM
  #27  
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Yea, there a so many places that could be leaking that would be pretty tough to spray onto.
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Old Jan 14, 2005 | 06:28 PM
  #28  
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Here is a trick I came up with some years ago to detect a vacuum leak that can not be located using the propane/ether trick.

Get a bicycle tire intertube. Cut it once so it is not a circle anymore. Assuing you are NA go ahead and close up one end. Stretch the other end around your MAF or TB. Using a air compressor or even a bicycle pump, pressurize the intertube with the car OFF. Once you get a few PSI in there you will be able to hear any leaks that are there. Use soapy water and a paintbrush to locate the exact spot of the leak.

Good luck!
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Old Jan 14, 2005 | 06:59 PM
  #29  
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Great idea...I will give that a try...
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Old Jan 14, 2005 | 11:31 PM
  #30  
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Now that's using your noggin bomax.
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Old Jan 15, 2005 | 10:41 AM
  #31  
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lol, learnt somthun new today.. propane ... i like the smoke trick better.. lol
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