Originally posted by hegill
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What I don't understand is:
1) What's the timing supposed to be at idle with no advance on the Holley EFI setup?
1) What's the timing supposed to be at idle with no advance on the Holley EFI setup?
http://www.masterenginetuner.com/top...all-fails.html (Crank Reference Angle Importance)
2) In the manual for the 3.5" handheld it shows a picture where the ignition timing at idle is 20°, but then says that for the idle timing typically anywhere from 18 to 34° is used. Do these values represent the Static Timing plus the advance that the ECU adds?
3) How can I determine what the actual timing is at idle with no advance, if this is a combined value?
When finished, the timing as viewed on the laptop, should match what you see with the timing light, at all RPM.
Once the ignition timing is fully synchronized, the Timing Table can be tuned for each application.
4) If the ignition advance values need to be changed, is that done in the base timing graph or Base Timing Table or somewhere else?
The ECU needs an Ignition Reference Angle, so it can control the timing. (10° Ignition Reference Angle is correct for GM HEI & Ford TFI. The GM HEI & Ford TFI distributors are installed at 10° Ignition Reference Angle, but they're operating one crank revolution ahead, so they're retarding a lot. On a high RPM race engine, it's best to keep the amount of ignition retard (occurring from such an advanced reference angle) to a minimum, so it's not used on expensive race engines. Of course, timing accuracy is better with a crank trigger.)
http://www.masterenginetuner.com/top...all-fails.html (Crank Reference Angle Importance)
Example: An EFI distributor doesn't have a centrifugal advance & vacuum advance mechanism; that's all locked out if converting an old carbureted distributor to ECU controlled EFI ignition timing. So the initial & vacuum advance is combined in the "Idle", "Cruise" & "Deceleration" areas of the Base Timing Table:
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