PLEASE HELP!!!Car running lean after installing downpipe

[Conner foley]

I recently installed an FI CEL Proof downpipe on my 2021 Supra 3.0. I bought the car used and it was tuned before I owned it, but reverted back to the stock tune. Anyways, after installing the downpipe, the car had no codes for the first drive, then after that it got the code “P0171 System Too Lean Bank 1” and also “P2096 Post Catalyst Fuel Trim Systen Too Lean Bank 1”. I did the install myself, but this is the first car I’m really working on all by myself. I thought it was gas at first but I’ve gone through multiple tanks and it has not changed. Now, sometimes the light will turn off for days on end and then randomly come back. I thought it may be that I didn’t get a new gasket for between the turbo and the downpipe, or maybe I just didn’t get the seal good enough and air is getting in. If anybody knows what is causing this or if it is bad to drive with it I would appreciate it so much if you could help! Thanks!

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[itzTang]

I recently installed an FI CEL Proof downpipe on my 2021 Supra 3.0. I bought the car used and it was tuned before I owned it, but reverted back to the stock tune. Anyways, after installing the downpipe, the car had no codes for the first drive, then after that it got the code “P0171 System Too Lean Bank 1” and also “P2096 Post Catalyst Fuel Trim Systen Too Lean Bank 1”. I did the install myself, but this is the first car I’m really working on all by myself. I thought it was gas at first but I’ve gone through multiple tanks and it has not changed. Now, sometimes the light will turn off for days on end and then randomly come back. I thought it may be that I didn’t get a new gasket for between the turbo and the downpipe, or maybe I just didn’t get the seal good enough and air is getting in. If anybody knows what is causing this or if it is bad to drive with it I would appreciate it so much if you could help! Thanks!

warranty it but most CEL proof downpipe on this platform isnt really CEL proof

 

[tracer bullet]

I thought it may be that I didn’t get a new gasket for between the turbo and the downpipe, or maybe I just didn’t get the seal good enough and air is getting in.

It could be either of these things, allowing ambient air to get sucked in as the exhaust goes by, and the sensor is sensing it. No guarantees but possible.

 

[Thraxbert]

"CEL proof" downpipes aren't foolproof. Return it for another or accept the CEL.

 

[razorlab]

Did you put the 02 sensors in the right order?

Black covered wire is on top
Grey covered wire is on bottom

 

[Conner foley]

warranty it but most CEL proof downpipe on this platform isnt really CEL proof

"CEL proof" downpipes aren't foolproof. Return it for another or accept the CEL.

either way, the code wouldn’t be from the bank 1 sensor right?

 

[Conner foley]

Did you put the 02 sensors in the right order?

Black covered wire is on top
Grey covered wire is on bottom

Yes, the o2 sensors are in the correct spot

 

[itzTang]

either way, the code wouldn’t be from the bank 1 sensor right?

 

[concept]

It could be either of these things, allowing ambient air to get sucked in as the exhaust goes by, and the sensor is sensing it. No guarantees but possible.

That may be the reason.
Also:
Inspect the turbo to downpipe connection for soot marks.
Replace the old gasket and torque bolts to spec.
Check the O2 sensor wiring (no pinching) and connectors.

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