Small exhaust leaks causing this much headache?

[SlowGrandNational]

Just looking for some opinions. Hopefully I am on the right track.

Have been chasing an issue that I originally thought was tied to my factory MAF finally dying. Got a used translator from my dad and bought a AF10043 MAF which seems to be an 85mm so I set the translator to that. Picked up a new Bosch narrowband 02 and put a standalone(no logger) Autometer wideband in just to monitor values a little easier.

Starts up, idles fine in the driveway, drives good at little throttle for the first 10 min around 13.5-14.5 AFR, 128 BLM seems okay considering no boost or load really. Trouble comes once the car really warms up after around 10-15min. Reset ECU by disconnecting battery and do some 3rd gear pulls for info to set TT chip with scanmaster G as translator instructions suggested, 16-17psi and I am seeing 2-5° retard 14.1AFR, good fuel pressure.
Ease off and notice AFR jumps to 10:1 (gauge rich max reading, likely much richer as car stumbles) whiles going back to just cruising home at roughly 1100-1600RPM
INT 160
BLM 142
TPS .97
CLT 167°
The only time AFR comes back to a normal range of 12.5 - 13:1 is when I take my foot all the way off the gas. Shut the car off and let it cool down, start it back up and it idles good again.

Other info: 42lb injectors fuel pressure hood gauge shows pressure rising good with boost, but it does bleed off immediately after fuel pressure is primed, but I feel that is unrelated. Replaced narrowband 02 again. Double checked MAF setting, I do see it going to 255 on WOT. I cannot get chip to go into closed loop learn after ECU reset, I'm not sure what I am doing wrong there. Checked for vacuum leaks, there seems to be none. New R43TS plugs at the same time as MAF translator install.

What I did end up finding was multiple pin holes in the cross over pipe. 3 that I can see on the bottom of the pipe, they're little larger than 1/16th; I was able to confirm they're actual holes by sliding a 1/16th drill through them.
I am going to pull the pipe off and have it repaired as a short term fix, but could a few very small exhaust leaks like this really be causing these issues? I understand unmetered fresh air on the narrowband is making the car believe it is lean and adding fuel, but for it to go so rich that I see black smoke and smell unburnt fuel feels like there would be more going on. Sick today so I'm sitting inside second guessing myself thinking it could be something so simple. Hopefully car will be getting headers built soon so I am just wanting to repair and hopefully eliminate this rich issue.

 

[SlowGrandNational]

Just throwing this out there... Removed pipe. A few more pin holes than I thought, and some very close to flange. It makes this situation that much more believable that it was an exhaust leak causing such severe issues.

 

[dynoman]

Do you have a smoke machine ?? I use one to find any and all exhaust & intake leaks . There may be more that you just are not seeing , as in gasket & slip joint connections . Also on the intake side there are a million places for leaks that are not obvious , but the smoke will show it .

 

[SCOOBY DOO]

BLM's are telling you you have a pre turbo exhaust leak or vacuum leaks. Crossover pipe appears to be your issue. Get it fixed and fire it up and see if your BLM's fall back to normal. I ran the 85mm MAF. Base switch is 6 in the Translator.

 

[SlowGrandNational]

Do you have a smoke machine ?? I use one to find any and all exhaust & intake leaks . There may be more that you just are not seeing , as in gasket & slip joint connections . Also on the intake side there are a million places for leaks that are not obvious , but the smoke will show it .

I have a DIY smoke machine I used. I didn’t see any apparent vacuum leaks.

 

[SlowGrandNational]

BLM's are telling you you have a pre turbo exhaust leak or vacuum leaks. Crossover pipe appears to be your issue. Get it fixed and fire it up and see if your BLM's fall back to normal. I ran the 85mm MAF. Base switch is 6 in the Translator.

I had the pipe fixed. The initial start up was good, AFR was reading 14.7 when warming up, but settled down to 12ish while in drive way once warmed up. Once I took it for a drive AFR was good then suddenly shot back to 10(gauge max) with my foot barely on the gas just cruising and I could feel it starting to react to that and run poorly. I pull my foot off the gas completely and AFR goes back to 12ish and the engine clears up.

I checked for vacuum leaks with a DIY smoke machine I have and found none.
Swapped narrowband sensors to a new one today and swapped to another 85mm MAF I have just in case. Translator seems to be set up correctly. It is one that you adjust with a flathead and the arrow is barely there anymore, but I am getting no trouble codes that I assume I would get if it wasn't set up correctly.
Something I did notice that has me confused is when I do an ECU reset, it does remove the adjustments and puts everything back to 128, but it is not going into learn mode as the instructions suggest it should for a TT V5.7 chip. I wanted to do the full reset bc I had thought if it was trying to compensate for that exhaust leak previously then a reset and relearn would be the way to go. I also noticed that it is very rarely going into closed loop at all.
BLMs are changing as the AFR does. When just cruising and seeing good AFR the BLM is at 128. As soon as AFR shows it going rich I notice BLM going to 142.
What are the chances of a chip malfunction I wonder, I have had this chip for a long time, it might be the one I had in my prev GN in 2014.(This is the same drivetrain that was in that one, long story but it was a fresh engine, then car was involved in a flood.) Clearly I had exhaust leak issues, but the whole reason I started down this rabbit hole was bc I noticed the car seemingly going rich and breaking up while cruising to work a couple times when I drove it. I though it was my MAF dying so I grabbed the translator from my dad and ordered the wideband just bc it seemed appropriate at the time. I'll prob email TT Monday and see what they think. The car is getting a full custom exhaust built soon, as well as a roller cam set up so I was going to end up needing a retune anyways.

Thanks for the replies btw guys. It took me a couple weeks to get my pipe repaired. Just got it back this morn and got it on.