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      01-21-2013, 09:47 PM   #1
DallasBoosted
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One bank richer/leaner than the other

Those of you with one bank running richer than the other after a downpipe install, just wanted to share my experience...

Got my downpipes and exhaust and FMIC installed, and immediately the car ran awfully. I thought at first the procede just needed to be updated, so I drove home and got the procede updated to stage 2. No better.

Figured out finally that my primary o2 sensors were reversed, and now the car ran 99% better... but I still had a nagging problem.

Bank 2 was running much richer (1 point+) than bank 1. Bank 1 was hitting the targets but Bank 2 was way overshooting them, and maxing out fuel trims on the procede even with OL fueling at 100 on 14psi; at 17psi it was leaning out. Very strange behavior.

I acquired a Cobb AP, and then the car didn't lean out anymore at 17psi, it runs great. However Bank 2 is still 1 to 1.5 points richer than Bank 1. While Bank 1 would hit 12.5:1 perfectly, Bank 2 would be 11.2-10.9:1.

One nice thing was the Cobb AP also told me the *rear* o2 sensors were reversed. So I finally got around to getting those switched, cleared all my codes, reset adaptations... and now both banks hit 12.5:1 perfectly.

So your rear o2 sensors do something, they affect AFR's somehow. In case anyone else is having this problem; the procede did not throw codes for the rear o2 sensors. Perhaps CANClear was nuking them? I'm not sure.

Anyway, FYI, my .02, and all that.
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      01-21-2013, 09:53 PM   #2
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Which codes were you getting?

I also have a bank 1 lean code P0171 and P29E0 after installing the AR DP as well and I'm trying to see if it was also the O2 sensors or something else.

After I installed Cobb Stage 2 I still got P29E0.
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      01-21-2013, 10:08 PM   #3
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Quote:
Originally Posted by DallasBoosted View Post
Those of you with one bank running richer than the other after a downpipe install, just wanted to share my experience...

Got my downpipes and exhaust and FMIC installed, and immediately the car ran awfully. I thought at first the procede just needed to be updated, so I drove home and got the procede updated to stage 2. No better.

Figured out finally that my primary o2 sensors were reversed, and now the car ran 99% better... but I still had a nagging problem.

Bank 2 was running much richer (1 point+) than bank 1. Bank 1 was hitting the targets but Bank 2 was way overshooting them, and maxing out fuel trims on the procede even with OL fueling at 100 on 14psi; at 17psi it was leaning out. Very strange behavior.

I acquired a Cobb AP, and then the car didn't lean out anymore at 17psi, it runs great. However Bank 2 is still 1 to 1.5 points richer than Bank 1. While Bank 1 would hit 12.5:1 perfectly, Bank 2 would be 11.2-10.9:1.

One nice thing was the Cobb AP also told me the *rear* o2 sensors were reversed. So I finally got around to getting those switched, cleared all my codes, reset adaptations... and now both banks hit 12.5:1 perfectly.

So your rear o2 sensors do something, they affect AFR's somehow. In case anyone else is having this problem; the procede did not throw codes for the rear o2 sensors. Perhaps CANClear was nuking them? I'm not sure.

Anyway, FYI, my .02, and all that.
Yes, a DP fix will result in similar issues where one bank runs richer than the other.
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      01-21-2013, 10:10 PM   #4
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Quote:
Originally Posted by jyeah View Post
Which codes were you getting?

I also have a bank 1 lean code P0171 and P29E0 after installing the AR DP as well and I'm trying to see if it was also the O2 sensors or something else.

After I installed Cobb Stage 2 I still got P29E0.
I forget the numbers, but the description on the Cobb actually said "downstream o2 sensors reversed"
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      01-21-2013, 10:13 PM   #5
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Quote:
Originally Posted by DallasBoosted View Post
I forget the numbers, but the description on the Cobb actually said "downstream o2 sensors reversed"
Did you ever have a DP fix installed? If you cross wires 19 and 20 on the fueling subconnector you'd get the same error.
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      01-21-2013, 10:17 PM   #6
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Originally Posted by themyst View Post
Did you ever have a DP fix installed? If you cross wires 19 and 20 on the fueling subconnector you'd get the same error.
No. My rear o2 sensors were actually installed reversed by the shop who did the install. I had to physically reverse them again.
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