I have the day off which is a rarity these days. Messing around in Tuner Studio and auto tuned fuel tables a little, way better afr. Enabled decel fuel cut and messed with those settings until I found what I like. Still have surging idle and dying when stopping, I'm guessing they're related.
I did notice a vacuum line coming off a y split has a screw to cap it. I don't see where it was supposed to go however. I will post pics in hopes someone more familiar with the vacuum system on this car may know something.

 

I would hold off on doing too much with the car until the 640s show up. The popping and banging turning on/off is most likely the injectors choosing when to leak and drip extra fuel into the system. Makes tuning fuel a real bitch, the previous tune with super rich AFRs might actually be the right way to tune these injectors. If one is a little leaner than the rest, 11.0:1 might be the average afr, but one cylinder is 11.5 or even 12. Tune it to 11.8, and that lean cylinder is now 12.8 and you're in piston melting territory. Get those injectors in, it'll need a complete retune at that point too.


Edit: I'm also at the track all weekend, so I probably wont be able to respond much. Someone hit the wall so I've got a rare break while they fix the track.

 

That makes sense. Thanks Curly. I did read a couple posts where people actually said the yellow injectors wouldn't idle correctly in their car, so I think I'm spinning my wheels at this point. Enjoy track weekend!

 

I don't want to speak to soon, but I think I fixed the issue with idling and dying. Last night I was laying in bed trying to go to sleep, which is when I do my best thinking lol. I've never heard the bov on the car. So when I woke up I pulled it off. Someone had it tightened all the way. So I loosened it basically as loose as it would go and threw it back on. I also realized there was no clamp holding the vacuum line on it. It wasn't exactly a snug fit. So I put a clamp on it now my bov works and it idles perfectly and hasn't died again, yet. I'm going to go on a longer drive right now but I'm pretty sure that was the issue. I'm still getting turbo flutter along with the bov, should I buy a new bov or is that normal for these cars?

 

Drove for about 45 minutes. Idle is nearly perfect and it didn't die on me once. One time the rpm's dropped to about 500 but it caught itself. Not a fan of the bov sound this one makes and I think I may need to tighten it up a bit but it's much better now.

 

Been driving it on and off all day, hasn't died on me once. Idle is good. The bov has a delay when I let off in boost and seems to sort of hang open a second or two longer than it should. it's closed when it needs to be other than that. Ill probably replace it, it doesn't sound quite right to me.

 

Glad you sorted it out. Late night thinktanks are surprisingly useful.

Do you know what turbo kit is on the car? Maybe post a photo of the engine bay. When I had the BOV near the turbo I had no flutter, but now with the BOV near the throttle body I get some fluttering. I recently went down the same rabbit hole and changed out a few BOV's I had on hand before upgrading to a TurboSmart unit, but it still flutters a bit. I'm still not sure it's normal or good though.

 

It's a cx racing kit. Bov is on the cold side.

When I loosen the bov even a little it doesn't want to make boost. I know why they had it cranked down. I ordered a cheap one for now, I'll probably end up buying a turbosmart just want to get one in there that functions for now.

 

FWIW, the plastic Bosch BOV held fine with the 21-22psi mine was hitting. IDK where the limit was because I never reached it. Just plumb it correctly. Pressure comes in the side and vents out through what looks like the bottom. I had it wrong initially.