I have a very solid map (well I think so) for my High Compression/big-cam/ported head K20a2 with DBW. Everything is good across WUE/ASE and STT from cold to hot (including restarts). The only thing that is elluding me is the double start/keep starter cranking behaviour I see.
On every start (across CLT bins), I see the engine catch (ie RPM goes over cranking threshold), WUE/ASE kick in but the motor never starts first press. I need to keep the starter engaged for the motor to start - only for a second or so.
I tried locking ignition and also raising ASE, but nothing is helping with the double crank
Transition from 19 ms pw (fuel you dump to cold start) to 3 ms pw (0.3 secs after it bangs) should be smoother. Afterstart enrichment will help you with that
First off, there seems to be way too much fueling. You are most likely just flooding the engine every time you are trying to start it. Everything is just adding on top of each other, prime-pulse+cranking fuel+warmup enrichment. Too much fuel.
Secondly, lower your cranking threshold to something lower. The starter is only ever getting to around 200-250 MAX. Lower it to around 400rpms.
Not related (or it could be) but do you ever have problems with the car just straight up dying randomly on warmup or when coming to a stop? In your logs when the car did start and run briefly, it just abruptly dies, not stutter out and die, just dies as if you turned the key off. I am wondering if it is losing sync.
Thanks! No issues with the car straight up dying, its a race car and the short log I shared is just me hitting the kill switch. I am interested to understand the overfuelling as it starts strong, across all CLT ranges, apart from the double âcatchâ. However, I am not a professional engine tuner and further research using calculations based upon the injector flow does indicate the cranking table is way too heavy. More reading required! (PS the post idle VE/IGNITION map was tuned on a hub dyno by a pro). I wanted to use the DBW for idle (the pro map just uses igniton and fuel for idle)
I will have to look again when Iâm not on my phone in regards to your âdouble startâ whatever that means. Do you mean you start it and it dies right away and the. You start it again and it runs just fine?
As far as idle control, your tuner should be able to set that up for you.
More reading required! (PS the post idle VE/IGNITION map was tuned on a hub dyno by a pro). I wanted to use the DBW for idle (the pro map just uses igniton and fuel for idle)
