Forums/Z31P/z31-performance-upgrade-forums engine-management/Ignition timing (I'm confused or just stupid)
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ozzyrulez: (2010-04-28 17:09:39)
My main question is, how does the ECU do ignition timing? Isn't this controlled by where you have the distributor set? My JWT tune calls for 20*BTDC and I actually have it at 15* right now because of the boost creep I'm having. I was comparing my tune to another on Jason's site. I see he has huge amounts of ignition timing compared to mine. I'd love to add that kind of timing to mine. Especially after I add the meth injection but I'm unsure on how it works or if it even would.
NissanEgg: (2010-04-28 18:03:55)
Re: Ignition timing (I'm confused or just stupid)
ECU sees:
rpms from CAS (crank angle sensor inside distributor)
AFM voltage readings
CHTS voltage readings
Knock Sensor voltage (if equiped)
and WOT switch from inside the TPS.
Then the ECU determines how much ignition timing to adjust from from static timing (physically set timing with timing light).
If you you set the static timing at 15* when it calls for 20*, then the ECU will still adjust timing that it was preprogrammed for based on sensor inputs, but all timings will be 5* less since you set the physical timing at 15*.
ozzyrulez: (2010-04-29 07:49:07)
Re: Ignition timing (I'm confused or just stupid)
So basically the ECU is sending the fire command to the coil early/later depending on what you put into NIStune and that is just basically added to the 15/20* on the distributor. So my distributor being at 15* and the ECU calling for 18* at say 6000RPM, that turns into 33* Or am I way off?
Bernardd: (2010-04-29 12:47:25)
Re: Ignition timing (I'm confused or just stupid)
x
ozzyrulez: (2010-04-29 16:33:42)
Re: Ignition timing (I'm confused or just stupid)
Oh ok, now that makes sense. I was over thinking it I guess. Thanks guys.