Tuner tip: Log everything.
It is your window into the engine, what it's doing and what it needs. You can review and analyze the log on TunerStudio (good for settings and adjustments) or MegaLogViewer (much better for tuning analysis and diagnostics, so you know what to set in TS).
Before tuning cold start, you must set a good tune for warm running (the baseline everything works off-of) and warm starting. Here is a first-start outline I did to help with this: Successful Initial Start
. At least initially, the cranking, idle and high-idle areas must be spot-on before tuning cold starts. Extra functions such as closed-loop idle should be turned off so they don't confuse the tune or the tuner.
Here is one description I gave previously on tuning cold starts after tuning warm start, taking each startup/warm-up function as a separate step:
PSIG wrote: ↑
Tue Jan 07, 2020 6:14 pm
... Remember, starting is a series of events beginning with priming, through cranking enrichment, transitioned by ASE, to WUE. Taking it in clear steps one-at-a-time usually makes tuning simpler and more effective. When you get one working well, move to the next. Begin with a very good
warm-idle tune and warm restart, and on the next cold start adjust each event control to best values for immediate and solid response. If it responds well but then quits along the way, that's no problem, and just indicates you succeeded with that adjustment and need to adjust the next event control.
For another example; some like to zero all cold start/WU settings (no change from warm-start) so each step in tuning is very
clear, and the engine only runs as far as steps have been tuned. Then for example, key the power ON twice instead of once in order to double-prime. Did that cause instant firing on the first rev (after minimum sync) like when it's warm? If not, key it again for more fuel until it does. If that was 3ms, then set prime at your cold temperature for 3ms and test, then set cranking for extra fuel until it catches and gains to above cranking rpm then quits. When it does that add enough ASE to carry it for a few seconds then quits. Good? Then add WUE until it continues running. Tweak WUE so it is solid and strong as it warms.
Use whatever tuning scheme like that you can get your head around, and follow your steps methodically. Most find that once they get the first couple results, it all begins to make a lot more sense. Watch your logs and learn to interpret what the engine is telling you by its responses. This is tuning!