MS3 on a stock '99.

AFR's seem good with little correction, and I am satisfied with EAE and idle (almost all the time).

I am now to the point of tuning my start. Note that start to run transition is good at all temps.

Issue: At most CLT I need about 2 seconds of cranking to fire.

Question: At a given temperature, what is the recommended procedure to approach and optimize the Cranking Pulse (fuel) and the Duty Cycle (Idle Control Valve)?

Auxiliary Question: How much does the Priming Pulse affect the above?

 

I'd start with default crank duty % for the valve and tune crank fuel first. You might need to very slightly tweak the idle valve at cranking later, but I wouldn't focus on that if I were you. I'd focus on crank pulse. and yes prime pulse has a huge effect on cranking (protip: keep it very low or you'll flood and make you think you don't have enough fuel)

see my thread on tuning startup, I think it will help you even though I'm running ID1000's and e85

*edit: actually once you tune a solid cl idle and know the idle valve min/max and average % at idle numbers, you'll pretty much have an idea of what your idle valve settings at cranking should be, so do the idle valve test asap.

 

I did do the idle valve test and am using those numbers. I am also using target for the closed loop (not adaptive based on last setting). SO, should I use the same numbers for the cranking DC as I am for the idle DC? As in 25.4 for CLT at 180, etc (I don't remember the others off the top of my head).

That is what you seem to be suggesting.

 

I did set iac duty cycle to match idle at various temps. Now I start in about 600mS is cranking at the temps I have tried. I added a little fuel pulse at CLT=60F only.

Now I'd like to Change the subject slightly and ask Hustler, please point me to where I can learn about tuning spark advance properly, especially without a dyno.

Right now I have what seems to be OK for N/A, My '99 on 93 Octane seems very forgiving to advance, but I want it optimized.