Evo 9 Link G4+ Stutters on crank

Hi Guys,

I have an issue with my LINK G4+ on Evo 9 JDM MR, sometimes when i crank (usually during cold start but sometimes during warm restart), the engine stutters and stall out. I will need give it some gas to maintain the rpm for couple of secs before it can idle on its own.

I've attached a log file from Link Log

I have the same issue on my hydra 2.7 I believe it is running to rich on startup and re start. Ive been pulling fuel from the main fuel map and it seem to be getting better but still does it when its below 30 here in CO.

Its hard to tell from the log because I dont see a wideband or data from Lambda 1 but it looks like the injectors are bouncing off of minimum duty cycle which indicates a lean condition. I had a similar issue on my RB with a link ecu. I had a lean condition on warm restart which was not IAT related (your IAT looks a little hot but not terrible). and it was cured with a combination of tuning the post start enrichment tables as well as warm up enrichment. If you dont have a WB02 you pretty much need it. I permanently wired mine to the ecu for CLL and it is super handy at all times.

Need to see your tune also. It looks like you have very little crank enrichment or post start enrichment set up - but as Johnny says you will need a wideband to tune those. It also looks like your idle valve is no where near where it needs to be either.

How do I check if idle valve is in the right position? I have Link CAN Lambda but set it to only work 30sec after engine start to prevent thermal shock to the sensor.

I’ll check my crank enrichment and post start enrichment and report back

EDIT: My post start enrichment and crank enrichments are pretty much stock evo 9 values from link stock maps. Do i need to change them since im running GSC s2 cams

Yea those base maps are usually a "safe" starting point but by no means perfect. Changes can depend if you run modelled or mS fueling etc. the cams likely will make your engine happier with a little extra fuel at idle. but in any case I'd activate your lambda as early as possible and watch it. But really just make some mid level changes to those tables and see if it helps or hurts. if it hurts go the other way with the changes. I suspect you need some more fuel but that should be quick to figure out. On the idle valve you can compare the base position to the current pos. to see how far off it is. but if the car isnt maintaining idle thats not really worth checking at the time, you can check that when it gets stable.