Cam change

[jfclubby]

Hi everyone, just installing a new cam into my ls1 223/228 @.050 .580.588 and ground on a 114 LSA, once i close my engine up would it be safe to do my initial start up on the old tune that was running maffless and what parts of the tune should i focus on ajusting first and what are the normal things that need looking at with this type of upgrade. I do understand that i will have more of an idea once i fire it up and at this stage it might be hard to help me out. I have a V1 with a PLX WB02 setup that i purchased about 2 years ago. Done a little tuning with it and found it great. Any help would be awsome as i am new to the EFILIVE world of tuning.

[Delco]

It will run , it will idle rich and will need more air to keep it idling

[macca_779]

Prior to starting this is what I would do: Add 20% to your desired airflow. Take 5% out of your idle VE cells. Run Base timing of 23degrees to start with. That should get it started without throttle input. As it will be stone cold, take the oportunity to dial in desired airflow accurately with the RAFIG process. Keep it closed loop to begin with and log your STFT/(LTFT if your using them) to get fueling in the ball park. Then go Open Loop and Auto VE it properly.

[jfclubby]

Thanks for the info, could you please explain to me what the RAFIG process is, and i asume you're saying to log STFT/LTFT during the start up.

[odd boy]

Here is good talk about RAFIG http://forum.efilive.com/showthread.php?t=4661
And here about idle tuning http://forum.efilive.com/showthread.php?t=4661

And here is help from me (I got it from my PC, but I don't recall the source):

Short Term Fuel Trim (STFT): A rapid, non-stored fuel adjustment described by percent fuel error.

Long Term Fuel Trim (LTFT): A slow, averaged, stored fuel adjustment described by percent fuel error. Can be modified or reset to zero by firmware or reset to zero by user action (VCM Controls, removing battery power).

Fuel Trim Cell: A pointer to the FTC matrix (array) described by the LTFT boundaries of MAP & RPM and stored in RAM. Also includes cells for Idle, canister purge, WOT, transmission selection (P/N, gear) and AC on/off.

How it works (Closed Loop only!):
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The PCM reads the o2 sensor value and compares it with the last reading to see if it switched from rich to lean or lean to rich. If it hasn't switched, it averages that value with the last and uses the proportional o2 error tables to determine how much the pulsewidth needs to be changed to make the o2 switch.

This averaged value (filtered) is then turned into the STFT value. If the o2 has been rich for a while (filtered, averaged) the STFT goes negative, pulsewidth drops, and vice versus.

Now, if the STFT goes above/below a preset limit over a period of time (~450msec), the LTFT will be Incremented (if STFT+) or Decremented (if STFT-) accordingly. If STFT is *way out of whack*, LTFT will Increment or Decrement more rapidly based on filter values in the closed loop control.

When the engine operating conditions cause the FTC to change, the last LTFT value from the current FTC is stored in RAM to be retrieved the next time the engine returns to that particular FTC. The LTFT value for the current FTC is then loaded from RAM and the process repeats.