Good info. Please keep us posted. I am on the road currently, but if needed I will post my advanced start options screen so we can compare notes when I get home in a couple of days.
If it starts fine when warm, it sounds like you need to change your "Start Extra vs Temp" parameters as these are multipliers on your crank fuel table that are based on coolant temperature.
the "Start Extra vs Temp" will have no effect on cranking either when cold or hot. This table is only in use after the car has reached the "Crank Exit RPM" this is typically set to 400rpm.
Dave, I was going from what the new AEMTuner v2.9 Function Explanation was saying. With this program, the "Start Extra vs Temp" is a coolant-temperature dependent multiplier to the "Crank Injector Time" table while in cranking mode.
Maybe the new AEMTuner functions have changed somewhat and I should probably shut up to avoid the confusion. Just like the AEMTuner discrepancy for the fuel pump priming time.
The table to play with to get the start fuel correct is the "Crank Injector Time Table" it is in the "Engine Start" template. The best thing I can tell you to get this right is when the engine is cold and you crank it, if it does not start like it does when it is hot try cracking the throttle a little bit (maybe 2-3%) if it starts then you have to much fuel and not enough air. So you need to reduce the "Crank Injector Table" untill it will start without the use of the throttle. If you do not have enough fuel it will not start when cold. So increase the Crank Injector value by 10% at 0% throttle and try to start again. repeat untill it starts everytime. You may have to revisit this table in the winter if the temps drop. It is hard to put in too much fuel on startup, if you do flood the engine it is recommended that in the "Crank Injector Time Table" that you have the 80% throttle and higher part of your table set to zero. This way if you do flood the engine at startup you can simply hold the throttle to the floor and crank the engine to clear out the fuel without adding any more.
The "Initial Crank Pulse Table" will rarely be adjusted and is a one time shot of fuel that is injected as soon as the engine starts to crank but before the Cam or Crank Sync has been established. This is sort of like the OEM ECU's batch fire of all injectors but the amount of fuel injected for this is based off of coolant temperature. I have not had to adjust this to get a car to start correctly but could be of use for cars that sit for a long time or for really large temperature changes but most of these issues can and should be addressed in the "Crank Injector Time Table"
Thanks to some great input from DDozier I have my car's cold start completely dialed in. The Crank Injector Time Table had to be adjusted in small increments...three times. The initial setting was set to 44. At 48 the engine started better, but not perfectly. I inched the setting to 50, and once again it was improved, but not as good as I had hoped for. At 52 it starts perfectly. This is a stock engine with a low boost turbo setup running the 1st gen AEM EMS and 750cc Injectors. Thanks also to Cody and Devin for their help on the side.
Open sourcing these adjustments has been great. I look forward to more collaborative efforts as my skills improve. Thanks for the contributions from the highly skilled guys!
latest cold start values. just tested it with ~55F coolent and IAT temp. cranks right up especially with a little crack on the throttle!!! thanks for all the help everybody.
When does the cam/crank sensor sync occur? I imagine it is with in one engine revolution? What is the value exactly?! Is it possible to translate it to something more relate-able like millisecond?