DIYPNP poor start
 

Hi guys,

I have been tuning my car for a few days now, and I've made good progress with my fuel and timing tables, so start and idle is my current focus. The car cranks and runs for about half a second before dying and resuming cranking to start successfully the second time. I'm interested in adjusting the enrichment immediately after cranking passes over to ASE + Warmup. My wideband (innovate lc-1) seems to take a while to show meaningful information and so I'm unsure of my AFR during startup.

My question to you is whether or not there are other factors I should be looking into other than enrichment in order to improve the startup. The included datalog encapsulates the whole process so hopefully I can use it to determine what needs to be changed.

Cheers :)

You have the right idea. If it runs for half a second, I'd focus on longer ASE taper. Just because the MS manual implies that ASE is for the initial transition, I have places where I run 700+ cycles. I do suggest cycles vs seconds. I don't remember where one sets that choice.

I don't have TS at work, so I'm going off your description only, not the tune and log.

I wired my LC-2 to a plug-in power supply in order to tune starts. Was a pain, got me where I needed to be, now removed. Only works at home. To be more informative, I use a diode set that would allow the LC-2 to be powered by the plug-in Power Supply or the car's switched power, seamlessly switching over.

if you need ASE just to keep ti running, then you have bigger problems elsewhere.

Agreed. The long ASE times are to keep AFR where I want them after hot restart, not to keep it running.

My point to OP was meant that ASE can run more than a few mS.

My point about taking the manual with a grain of salt. I will give a second example: Early editions stated that Priming Pulse was to clear vapor. Newer additions site the value of Priming Pulse to wet the IM walls, which is now a common use of Priming Pulse. Code intended by the FW guys for one purpose can serve other purposes as well.

That all being said, do you think OP should be looking elsewhere, or were you encouraging me to improve my tune?

i think the issue could be the idle cranking duty and the ve table (in places it only touches during cranking and first start). obviously you have enough fuel injecting to start, but it's not sustaining. ASE doesn't need to run for long at all, it's to keep the AFRs fat for a moment so everything can stabilize. But the idle valve needs to be open enough at this point, and there needs to be enough fuel in the base ve table to actually idle.

a lot of people don't tune the 100 to 30 kPa row below 1500RPM where the fuel table is still being reference at/during/just after startup.

I'd also look at logs and see what's different between when it dies vs when it stays running. compare the VE%, idle position, AFRs, gammae%, etc.

Thanks, Scott. Bolded for truth.