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rich at idle - fine elsewhere??

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Old Jul 14, 2003 | 05:34 PM
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Default rich at idle - fine elsewhere??

I have been working on my tune a little bit for my heads/cam, but for some reason I just can't get the idle correct. The car idles fine - nice and smooth (well smooth for a big cam). I have the idle set at 925 rpms. But at idle, the car is horribly rich -- you can smell it sitting at a stop light. The car runs great everywhere else, and my ltfts are in good shape. My IAC counts are also fine - the TB has been drilled (and is ported - bauer).

I just want to lean it out at idle so that people stop passing out behind me at stop lights.

Any thoughts?

Thanks
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Old Jul 14, 2003 | 07:23 PM
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Default Re: rich at idle - fine elsewhere??

First, make sure that your Lterms are fine at idle. There are some conditions that will cause high Lterms at low engine RPM and cause excess fuel to be dumped.

Here are some things that you can try.

1) On your injector flow rate table play with the values around 50 MAP. This is where your idle hangs out at on the injector flow rate table. Make small shifts up (multiply greater than 100%). If the car starts to stumble, or looses throttle response go back to where you were.

2) Raise your cam idle speed. On large cams the overlap can goof up the O2 sensor reading if the cam is barely keeping the car alive. For a cam the size that you listed, I always have the idle over 1000. For kicks try something absurd, 1100 rpm and see if it cleans up.

Good Luck,
Kevin
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Old Jul 15, 2003 | 11:39 PM
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Default Re: rich at idle - fine elsewhere??

Clasic thanks for asking that question, and Kevin, thanks for answering it! I have the same problem so this info should help me also.
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Old Jul 17, 2003 | 12:04 AM
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Default Re: rich at idle - fine elsewhere??

Did this help you guys? I multiplied mine by 102 and I'm still rich. I haven't had a chance to do any more but I'm gonna play with it some more tomorrow. If it did help, what cells did you change?
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Old Jul 17, 2003 | 12:00 PM
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Default Re: rich at idle - fine elsewhere??

I scaled the VE 1200 rpm and below by 60% instead, that solved the rich idle problem I had. I think 60% was a little too extreme though, gonna try 80% tonight.
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