PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

timing issue

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Old Apr 21, 2019 | 06:13 PM
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From: NH
Default timing issue

my timing is dropping to 4degrees when letting off the throttle. I believe this is causing a annoying popping through the exhaust the popping is pretty loud. my dfco is turned off I believe. posted latest tune and scan
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gas run.hpl (1.78 MB, 45 views)
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Old Apr 25, 2019 | 05:20 PM
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nobody?
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Old Apr 26, 2019 | 12:49 AM
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Really looks like your adaptive spark is pulling it out. On my scanner when you are letting off the throttle, it is registering up to 400-500 rpm error from "desired idle" after about 3-8 seconds depending on your RPM (out of idle routine) so the PCM is pulling spark quick to target it when it resumes idle routines, and that is 14* on your table.

You could add some more spark to the idle tables as well as reduce the adaptive overspeed table a bit in these areas. Legend has it 32* is max torque at idle, so using that, adding to and reducing accordingly on the 2 tables will move your low numbers higher taking the total range down. Say if you push idle spark to say like 22*, then set the overspeed to 10, and I'll bet the lowest it goes is 12 after that. This you will have to experiment with to see what works best. I typically run smaller numbers on the overspeed table for this reason, unless the engine is hanging on too long, which also can be an airflow problem, and usually is.
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Old Apr 26, 2019 | 05:49 PM
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Default tune

yes the throttle does hang a little after I let out of the throttle. did u see that in the scan? tried to decreese braf but I believe im already too low as my iac numbers at idle seam to be around 0-30 counts. but car idles pretty good what is your recommendation. im open to all opinions. darthv8r has help me out a bunch he is the reason car idle as well as it does now.
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Last edited by JHZ28; Apr 26, 2019 at 06:14 PM. Reason: adding stuff
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