Problems dialing in crank pw
 

Hey everyone,

I cannot for the life of me dial in a consistent crank pulsewidth for my 92 miata. I am trying to get it setup on stock injectors. Once the car is warmed up (180-190F) it'll crank nicely anywhere between 50-75. I've tried messing around with my injector dead time using the provided 1.2ms to start out with. Was using .9 for a bit and now have it set to .71 using the 2-4 squirt cycle method. At this point I'm wondering if its possible to get a consistent start cycle on stock injectors. From what I've ready most people don't have this big of an issue using DIYAutotunes stock base map. Outside of my starting issues the car runs and drives great.

Edit: I'm using a self built Megasquirt DIYPNP

Dead time is a global constant for your injectors. You could set it to 2.0, or .5, or whatever, your tune will just have to change a lot, but you should be using the dead time published for your injectors. That’s why after market injectors are nice, you actually get that information. But it doesn’t affect cranking any more than any other part of the fueling calc. If you're having issues starting, try more fuel by adding cranking PW, and try adding more fuel with cranking idle duty.

I've only messed around with cranking pw not cranking idle duty. I believe that setting is only available if I'm using closed loop idle, currently I'm idling on open loop. As for crank pw I've tried tuning it by adding/removing based on what happens (if it takes a couple key cranks it generally needs more pw/fuel?). On a warm engine shouldn't the crank pw multiplier be roughly 100 if your deadtime is set correctly? So the fact my engine starts best around 50-80 crank pw means something is pretty off? Those values also don't change all that much from .7-1.2ms deadtime which is a pretty large range. I agree that my life would probably be a lot easier if I bought aftermarket injectors with specified values. I'll try actually making the plot to verify deadtime.

Edit: I don't have issues starting, just issues starting smoothly. I'll get a a kind of pfff sound from my engine and then I usually have to crank the key a second time for it to start. After that it starts up fine. I originally thought this was due to needing more fuel (more pw), but could it be do to needing less fuel (less pw)? I've also tried adjusting all the crank pw values at all the different coolant temp values as the engines warming up.

https://cimg3.ibsrv.net/gimg/www.mia...4ddbeaf7a9.png

Something doesn't seem quite right with my dead time graph. Looks like I have two distinct curves, first one's intercept is roughly around 1.2ms, while the 2nd's curve intercept is around .1ms...

https://cimg6.ibsrv.net/gimg/www.mia...2ff4e465e7.png
Better image that actually shows distinct data sets.

hi
I'm not having trouble getting started; it's simply getting started nicely that I'm having trouble with. My engine will make a pfff sound, and I'll have to turn the key again to get it to start. It runs smoothly after that. I assumed it was due to a lack of fuel (higher pw), but could it also be due to a lack of fuel (lower pw)? As the engines warmed up, I tried altering all of the crank pw settings at various coolant temps. turkish citizenship requirements