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P2096 and P2196 CEL after Cobb Turbo-back Exahust Install

jtmu6982

Passed Driver's Ed
All,
Before Turbo-back install: I have a Cobb AP, APR Stage 1 & 2 intake, flashed to Stage 1+ (stock MAF, 93 Oct)
After Turbo-back install: Cobb AP, APR Stage 1 & 2 intake, flashed to Stage 2 (stock MAF, 93 Oct)

The car was running fine before the Cobb Turbo back installation: no codes, running smoothly, no issues

I took the car to a local shop and had them install the Cobb turbo-back. Got the car back, it was running roughly (stop to start it was abnormally loud imo, lots of rough noises as the car gets up to speed, etc). After driving the car roughly 10-15 miles, I got a CEL. I read the codes with the Cobb AP as P2096 (Post Catalyst Fuel Trim System Bank1 Too Lean) and P2196 (02 Sensor Signal Stuck Rich Bank 1 Sensor 1). This is puzzling to me as I have read this exhaust system (provided you have the proper levels of mods) is a simple bolt on utilizing OEM sensors according to @COBB Tuning. To be fair to @COBB Tuning, I do not have their air intake (I'm running the APR) but would this make a difference provided the car breathes better for the mod/tune?) The only reason I did not do this installation myself is because I do not have access to a lift, blocks or any equipment to get the car up off the ground so I could get under it and work. I am regretting this now.

Possibly causes I am thinking (tell me if any of them are wrong as I am somewhat of a noob):
1. O2 sensors are reversed (A is installed where B should be and vice versa)
2. There is an exhaust leak somewhere in the equation where the pipes meet together
3. Bad 02 sensor(s), although this is hard to fathom since there was no problem before this installation.
4. Dirty MAF sensor (I am running OEM here)

Any thoughts or experience on this would be greatly appreciated. Thank you in advance.
 

torga

Autocross Champion
If a rear O2 sensor spacer wasn't installed, that's likely it. I recommend the Vibrant 11619 J-style. Most of us get the P2096 code after installing a downpipe, almost in the same time-frame you provided.
Installing the O2 spacer is quick and it's about $25. You'll have to take it back to the shop since you don't have a lift, though.
 

Francoleon91

Drag Race Newbie
I had this issue for the longest time, those two annoying ass codes. it was an exhaust leak were the DP meets the turbo. My DP was soo loose but i never realized, got new bolts and gasket, tighten the fuck outta of it and the codes NEVER came back, havent seen them in months. Id have a shop take a look.
 

torga

Autocross Champion
I had this issue for the longest time, those two annoying ass codes. it was an exhaust leak were the DP meets the turbo. My DP was soo loose but i never realized, got new bolts and gasket, tighten the fuck outta of it and the codes NEVER came back, havent seen them in months. Id have a shop take a look.
Ouch, that would suck if OP's shop reused the gasket.
 

torga

Autocross Champion
According to Cobb, you use the factory turbo gasket where the DP meets the Turbo...
Right, you always do. But a new one. You shouldn't be reusing the one that was already there.
 

jtmu6982

Passed Driver's Ed
Just to update everyone:
I flashed the car back to Stage 1+ which is the stage the car was in before the exhaust installation.
I reflashed back to Stage 2 to clear the codes and to make sure the problem was not in the "tune."

I have driven the car approximately 60 miles today and no CELs as of yet. From stop to start in the lower gears, there is a lot of vibration and rattle sounds seemingly underneath the area of the dashboard. I don't know if this is a normal sound or if it should be a constant sort of growl (low tone) on acceleration from stop to start? I am taking it to the shop that installed it and getting them to look it over and maybe check the connections.

There is also a strong exhaust/gasoline odor in the cabin of the car. Like an overwhelming smell. I have heard that you get a little bit of that with an aftermarket DP but this is a strong odor.

If I throw any CELs I'll try the 02 sensor spacer mentioned above. For now, I guess I'm going to roll with my plan of taking it back to the shop and getting them to look it over. I will update as I get more information as it may help someone else.
 

jtmu6982

Passed Driver's Ed
Also, HJ @COBB Tuning has had me send him a datalog file to review for issues. Their customer service is awesome.
 

Attachments

jtmu6982

Passed Driver's Ed
Right, you always do. But a new one. You shouldn't be reusing the one that was already there.
Oh, I gotcha now. I guess I could purchase one of those from @ECS Tuning or perhaps @COBB Tuning and make sure that seal there is snug.
 

jtmu6982

Passed Driver's Ed
By the way, thank you all for helping me out with your responses!
 

torga

Autocross Champion
I have a strong suspicion that Franco is right and the shop didn't seal up the connection to the turbo well. You're citing rattling in the area of center dashboard and immediately underneath that is the turbo/DP connection.

If it's a catted turboback, the raw exhaust smell should almost be nonexistent. If it's catless, well, you'll just have to deal with some raw exhaust seeping in. But it shouldn't be overwhelming, as you're saying.
 

jtmu6982

Passed Driver's Ed
Yeah, I’ll mention that to the shop when I take it in and report back.
 

torga

Autocross Champion
Godspeed.
source.gif
 

jtmu6982

Passed Driver's Ed
Just to update everyone. There are apparently several bungs by which either a sensor goes in the various sections of the exhaust OR a threaded plug should be inserted. Well, the technician did not put a threaded plug in one of those. He did so upon me taking the car back. The car runs & sounds perfect now w/ no CELs. Apparently, the bung that was open was in the neighborhood of underneath my dashboard. That was where the strong odor was coming from along with the subsequent lean readings. Thanks all for your help.
 

torga

Autocross Champion
Man, annoying. It happens. Glad you got it figured out (hopefully) without spending any extra money! Enjoy the sounds and the power.
 
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