Closed throttle spark.

[Sunny Jim]

So we sit around and we discuss the pros and cons of different tuning aspects.
Eg. Closed throttle spark table?
Is it essential or should it be flattened with just one value (eg. 20 degrees)?
And should the spark gain be switched off?(zero'd)
Feel free to jump
Right
In.

[Ohio HD]

My understanding is it's there to allow a smooth transition from idle to throttle opening. I had been told in the past that if the lower RPM values are too low or too high you may get a stumble when opening the throttle from idle.

I've always tried to keep the values in line with the main spark table at those same RPM's. But I also have used the Closed Throttle Spark table to help with decel pop.

[Ohio HD]

This the way my 124" TC is setup. The 30° values I added to stop decel popping. I added fuel to stop the popping, but still needed the timing change.


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[98fxstc]

There is some really good info on this in hdforums.
Rather than me try to explain it here, you should go and have a look there.
wurk truk, a former member here was very passionate about tuning and gave out a lot of advice to DIY tuners.
Check the TTS Mastertune sticky thread, and in particular post #4238 and go from there.
This was about 2013 but still relevant.

[Ohio HD]

Might be a good idea to search Closed Throttle Spark here on HTT. Several posts from the past on the subject.

[hrdtail78]

I use it to set no load timing.  This can usually be higher and I use engine idle smoothness by feel to set.  Since the idle target is closed loop and it uses spark and air flow to keep this target.  I do not shut the gain off, and allow the ECM to continue to use ignition to control idle speed.  One of the reasons your Closed Idle table and what the data is reporting at idle is different.

Close throttle spark allows a smooth idle and allows the main to take over when TPS and RPM is in same area as idle but load is applied by clutch lever.  As pointed out.  It's also a table to address closed throttle decel.