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Old 09-29-2011, 02:14 AM   #1
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I study the manual fairly often and I have not found the answer to what really happens when the engine smacks the rev limiter. I'm assuming the PCM simply turns off the injectors. I don't get the feeling the ASD relay is turned off but more that the fuel is just cut. Anyone have the real scoop on this and can direct me to where the information is available?
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Old 09-29-2011, 05:18 AM   #2
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Sorry Chief!! Not a clue. Superchip always took care of that little issue.
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Old 09-29-2011, 07:11 AM   #3
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It is hard to find any info on exactly how our computer controlled rev limiter works. My guess is it cuts fuel and spark.
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Old 09-29-2011, 04:20 PM   #4
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Old 09-30-2011, 07:07 AM   #5
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My guess is, that it backs off the throttle. If it cut the spark, the cylinders would fill with un-burned fuel/air mixture. When spark was re-introduced, you would have a good chance of blowing something up. If it cut the fuel, you would have a lean condition. Not a real good idea at high RPM's. It's also possible it cuts the spark every other revolution.
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Old 09-30-2011, 07:24 AM   #6
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Good points, I was reading about the new MSD 6013 unit which takes over control of the ignition timing of the hemi engines and is still compatiable with the PCM states that it has two adjustable rev limiters available. One for launch another for peak rpm up to 12500. This would lead me to believe the PCM controls ignition to act as the OEM rev limiter. I email their tech support to confirm that the OEM rpm limiter was not active when this unit was in use. This unit can also eliminate the waste spark and makes timing fully adjustable. Too bad it does nothing for tuning fuel.

Edit: I recieved a response from MSD and was told as I expected that the MSD 6013 cannot over ride the OEM rpm limiter. It completely replaces the entire ignition system but uses a OEM ignition trigger. So this must also mean that the rev limiter is the ignition controlled by the PCM. Now if we could substitute that ignition trigger, we could have full control over the timing.
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Old 09-30-2011, 02:19 PM   #7
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Old 10-07-2011, 01:37 AM   #8
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Still haven't recieved anything from MSD tech support.
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