need help edit timing table
As far as the low octane table is concerned, there are different opinions on that. Some say for safety’s sake, leave it alone. But I always use 93 octane gas so I copied my high octane table to my low octane table. As long as I never get a hold of “bad” gas, I should be ok. As I understand it, the computer will go to the “low” table for several different reasons, even when you are just low on gas, so I don’t have to worry about that.
You have to create a calc. PID to log cylair.
{SAE.J1979.MAF} *15 / {SAE.J1979.RPM}
I export g/cyl, rpms, timing, knock, TP and VSS into excel and then adjust timing accordingly.
http://www.starrperformance.com.au/e...alculated_pids
As for you question about how the computer figures out how to do timing, the following is from GM Service Tech: (but we seem to be able to control it by editing the high & low octane tables)
“Circuits Affecting Ignition Control
In order to properly control the ignition timing, the PCM relies on the following information:
The engine load, based on the manifold pressure or vacuum
The atmospheric or barometric pressure
The engine temperature
The intake air temperature
The crankshaft position
The engine speed (RPM)
The Ignition Control (IC) system consists of the following components:
The ignition coils
The 24X crankshaft position sensor
The Powertrain Control Module (PCM)
All connecting wires
The ignition control uses the following signals and circuits in order to control the spark timing functions:
The 24X signal-The 24X crankshaft position sensor sends a signal to the PCM. The PCM uses this signal in order to determine the crankshaft position. The PCM also utilizes this signal in order to trigger the fuel injectors.
The Ignition Control (IC) circuits-The PCM uses these circuits in order to trigger the ignition coils.”
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