What tables or parameters do I modify in tuner pro to help with cold starting?

Car starts up instantly when temperature is above 50 degrees, but today I had to hold the pedal down to start it since it was only 32 degrees.

 

Much like the VE table during Closed Loop, we essentially "fix" the Open Loop table during Open Loop conditions in the Open Loop - AFR vs RPM table. However, you will maneuver that Open Loop target depending on coolant temperature with the following;

Open Loop - AFR Multiplier vs CTS

You stated that the engine starts good at 52 degrees Fahrenheit (11 degrees Celsius), but poorly at 32 degrees Fahrenheit (0 degrees Celsius). Now, this is assuming you need to feather the throttle until it warms up to maintain an idle (if you don't have to feather the throttle under 52 degrees to keep it running it would be a cranking fuel issue, but you stated you have to hold the pedal down). You will go into the table I listed above, and change the AFR target via coolant temperature. So simply put, you will increase the fueling demand by lowering the target AFR at 8 degrees down to -40 degrees Celsius in the table.

Example;

The current multiplier setting at 8 degrees Celsius (46 degrees Fahrenheit) for the L98 bin has a value of -14.06. This is telling the system to reduce the AFR of 13.80 found in your Open Loop - AFR vs RPM table by 1.94 (13.80 x -14.06%), targeting an 11.86 AFR at 46 degrees Fahrenheit. You will want to increase the amount of fuel as the temperature gets colder, so lower the AFR target by increasing the negative percentage that is being multiplied. So if you wanted, say, a 10.80 AFR at anything lower than 52 degrees Celsius (lets use the 8 degree Celsius target for example, which is 46 degrees Fahrenheit), you would enter the value of -21.88 replacing the -14.06 that is already there, which is a reduction of 3 AFR points (13.80*-21.88%) = 10.80 AFR @ 46 degrees Fahrenheit...

- Rob

 

I actually only need to hold the pedal till it starts, once it starts up I no longer need to have my foot on the pedal. I did mess around with the table and it is starting up well so far.

 

Remember that you are tuning a range. The IAC on the WUD screen will embellish its' initial target when starting, anywhere between 125 and 145 steps. If you are stalling at colder temperatures, but not at warmer (you stated it is perfect at 52 degrees Fahrenheit and up), then changing the settings for the IAC will disrupt it from 52 degrees and higher (I mention this because the original response in the email stated you changed the IAC settings). If it is just the initial startup and you do not need to hold the pedal down, then as mentioned, add fuel to the cranking tables in the particular area in relation w/the coolant temp. I am responding to this for the others who might be reading along.

-Rob

 

When you 'hold the pedal down' if that means all the way down, is this not a clear flood remedy? Which would mean it is too rich? Would the clear flood be corrected with crank AFR table?

 

My current problem is the CAFR is say 9 and my wide band O2 shows 11 during cold start. So what needs to be changed to get the WB O2 closer? If I open the throttle slightly, the engine will stall until coolant temps warm up.

 

No, meaning feathering the throttle. If you start the engine when cold and it catches, but immediately after it wants to stall, and you find yourself feathering the throttle to keep it alive, then you need to add fuel to the Open Loop - AFR Multiplier vs CTS...



Your wideband is showing the correct (physical) AFR in the exhaust stream, whereas your CAFR is only embellishing the targeted AFR, which isn't reading anything, it's just indicating what you are commanding until Closed Loop is realized. Whenever there is a deviance in AFR using the wideband, it's usually found in the VE table. Every cell in the VE table should be close to, if not exactly 14.7 AFR. Everything else works in tandem with the VE Table (multipliers, etc). Think of your Open Loop AFR table. With no O2 feedback, how would the ECM know you are commanding, say, 11.0 AFR when cold? It uses your VE table because that area is (rather should be) perfectly stoich, This is also why when you suddenly enter into PE mode, your INT/BLM should immediately be reading 128/128, otherwise the fueling is off...

- Rob