Very Lean Idle
01-11-2005, 03:13 PM
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Very Lean Idle Trying to tune this 408 motor...
Whatever I do in Edit, this is what happens every time...
1. Start the car, idles pretty good with 13:1 AFR
2. Starts to warm up and the AFR slowly works its way to 17:1 and then goes leaner and off the scale....and starts to run like ****..
Anyone know what this could be? I have even tried scaling the IFR down way below the value that it should actually be and it does the same thing every time.
Whatever I do in Edit, this is what happens every time...
1. Start the car, idles pretty good with 13:1 AFR
2. Starts to warm up and the AFR slowly works its way to 17:1 and then goes leaner and off the scale....and starts to run like ****..
Anyone know what this could be? I have even tried scaling the IFR down way below the value that it should actually be and it does the same thing every time.
01-11-2005, 05:20 PM
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What injectors are you running?
Are you running closed loop, open loop, with or without MAF?
What kind of cam do you have and what heads do you have?
The start-up enrichment is what is starting you off at 13:1. However, as the ECT warms up, the target EQ ratio becomes 1.0 or 14.7 AFR. Your VE table values are too low down in the idle RPM/MAP range on the VE table.
Tell us more!
Steve
Are you running closed loop, open loop, with or without MAF?
What kind of cam do you have and what heads do you have?
The start-up enrichment is what is starting you off at 13:1. However, as the ECT warms up, the target EQ ratio becomes 1.0 or 14.7 AFR. Your VE table values are too low down in the idle RPM/MAP range on the VE table.
Tell us more!
Steve
01-12-2005, 09:29 AM
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Issue was vacuum related:
https://ls1tech.com/forums/pcm-diagnostics-tuning/260356-idle-lean-condition.html
https://ls1tech.com/forums/pcm-diagnostics-tuning/260356-idle-lean-condition.html