Hello all,
I have to start with a short explanation: Ive done a LSswap to 2012 model year car in Europe what means I have to fullfill Euro5 emmission homologation to get aproval for road use. This means not a simple emmission test as done every two years here. A 11km run from cold start (engine/ECt, etc. @20?C) on a dyno style test setup inside a laboratory has to be performed and the total emmissions are not allowed to exceed the limits of E5 spec.
The engine used is a 2013 production LS3 out of a Gen5 Camaro. Airbox changed due to swap, routing of ignition cables slightly changed, aftermarket clutch with a slightly lighter flywheel. Also I currently run shorty headers and HJS 200cpi E5 catlysers, but I plan to change them for production style headers and catalysers. Belt routing is slightly changed, besides that the engine is bone stock. So far the car is running great with no issues. Also a regular emmission test can be passed with close to perfect numbers. (car is tested hot and stainary at specific rpm?s in that case)
I have done a first test run in the laboratory and it turned out ( as expected) that the cold start is massive issue emmision wise. After further testing, datalogging and emmision measurements I found out that the first 30s seconds directly after cold start are generating the majority of total emmissions. From the calculations Ive done roughly 50-80% (depending on which parameter) is generated during start up.
As well, the fuel priming seems excessive. I loges up to 110ms priming duration directly before cranking. As well AFR cmd is 11ish direct after start and goes up to 14.68 within a few seconds. From the signals I see on the upstream O2 (unfortunately no wideband logs yet) the engine is running very rich in the first 5-10s, since signals stay maxed out. (I know, those are digital sensors) As well a very strong fuel/emmission smell (like a non cated engines running rich) is noticeable in the first 30s after cold start.
EDIT: I should mention that measured HC and CO values are excesively high during that first 30s and are reducing dramitically after 10-15s more. Under idle, catalyst start to fully operate after roughly 7min based on downstream O2 signals. But emmission values are already close to acceptable after 50-60s. Fully in spec after 5-6min.
What I want to do now is lean out the cold start as far as possible, meaning as far as the engine is still able to perform a reasonable startup @20?C. For that prupose I searched for any crank priming/crank AFR/crank Airflow/crank VE table, but I wasnt able to identify anything like that.
Closest I get is fuel/general/FA mult stage 1 (I dont see a stage 2) and fuel/openloop/IVT gain gas. But the second named table seems not to affect the area to consider for cold start and running at low rpm. So Fa mult is pretty much the only strain I could follow.
I didnt realy tried this table yet in depth, but from what I learned yet it seems that this table cannot solve my issue.
Is there any other table I could look at? Is the priming table maybe something I have to request at the support? If yes, whats the code for this table and are there others I shold also request?
I added my current tune (what is stock in matter of most of the relevant bases and just modified to work with the swap car) and a cold start log @idle for reference.
Thanks in advance!