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Author Topic: FiTech Startup Tunung - Minimal Prime Shot  (Read 621 times)

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Wheelman

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FiTech Startup Tunung - Minimal Prime Shot
« on: August 17, 2018, 02:54:33 PM »
From the FiTech Owners Facebook page...
This particular setup method focuses on using a minimal Prime Shot to get the engine to fire, then use Cranking Fuel to complete the start.


Before you make any changes you need to do yourself a favor and back up your config or at least write down the changes you make.
This should be done religiously and without exception.

Take it from someone that has learned the hard way.

The start cycle actually has multiple unique parts.
There is:
“Prime”
“Crank”
“After start”
“Warm up”
and they work in the order listed.
Josh Williams has a cold start video on YouTube that should be viewed as well and it may even have a link in the pinned post.

My suggestions below are based on a warmed up motor because it establishes the baseline for cold starts.

Once you have this set getting the cold start set is rather simple.

BTW my 496 is starting pretty nice with ~7” of manifold vacuum.
Thanks to guys like Marty Neighbour and Josh Williams for helping me get here.

So.....
Prime is the initial wetting of the plenum to help with the start. The default value is WAY TOO BIG in my opinion.

Crank is fuel applied only while the engine is turning over and below a default threshold RPM (I think it is 500rpm).

After Start is for the duration of time between the Crank cycle and when the motor reaches your set idle rpm.

Warm Up is after you reach Idle rpm and under a default threshold Coolant Temp. (Getting here is your goal)

Knowing this my suggestion is to cut the Prime value down to as small as possible (~40-50). If you can go lower then great.

You are seeking a point where the Prime is minimal and Crank is really adding enough fuel to let it initially fire... it may immediately die and that is ok!!!! In fact it is near perfect.

Once you hit that point increase the After Start.
If the engine stays running without touching AfterStart look at the AFR readings. If they are rich turn down the After Crank by 10-20.
You should eventually find a spot where hitting the key gives the minimal Prime, enough Crank to hear it fire followed by just enough fuel to keep it idling at the desired RPM.
« Last Edit: August 17, 2018, 03:14:27 PM by Wheelman »