Closed loop poor performance. Open loop fine.
Thread Starter
Teching In
Joined: Feb 2017
Posts: 6
Likes: 0
Closed loop poor performance. Open loop fine. 2012 CTS-V no mentionable mods. CAI.
Noticed some sluggish performance a few weeks ago. Turned out the CAI had came loose from the TB. So it was pulling air outside the filter. Fixed that, but still had poor performance.
Did a few test drives but my tech couldn’t find any unusual values on the snap on. O2’s seemed to be okay, jumping around like they should. Fuel trim was a bit lean but nothing serious. However he noticed performance was only sluggish in closed loop. Open loop it pulls just fine.
By by poor performance I mean low rpm wot it just accelerates poor. Unless - it’s in open loop. Which doesn’t always happen. I’m unsure on what condition it’s supposed to happen. So here’s what I’ve changed so far :
new zl1 lid. Suspected maybe the brick was leaking. It wasn’t. Oh well.
New plugs -
new maf - acdelco
new wires
new knock sensors
new o2’s upstream and downstream NTK
new temp sensor in the lid
car has a few misfires on all cylinders - but nothing persistent. I’m talking like 2 maximum 4 randomly on random cylinders. No cel.
65K miles
any ideas, pointers ? Could it be the tps or the tb ? The cats?
Noticed some sluggish performance a few weeks ago. Turned out the CAI had came loose from the TB. So it was pulling air outside the filter. Fixed that, but still had poor performance.
Did a few test drives but my tech couldn’t find any unusual values on the snap on. O2’s seemed to be okay, jumping around like they should. Fuel trim was a bit lean but nothing serious. However he noticed performance was only sluggish in closed loop. Open loop it pulls just fine.
By by poor performance I mean low rpm wot it just accelerates poor. Unless - it’s in open loop. Which doesn’t always happen. I’m unsure on what condition it’s supposed to happen. So here’s what I’ve changed so far :
new zl1 lid. Suspected maybe the brick was leaking. It wasn’t. Oh well.
New plugs -
new maf - acdelco
new wires
new knock sensors
new o2’s upstream and downstream NTK
new temp sensor in the lid
car has a few misfires on all cylinders - but nothing persistent. I’m talking like 2 maximum 4 randomly on random cylinders. No cel.
65K miles
any ideas, pointers ? Could it be the tps or the tb ? The cats?
Staging Lane
Joined: Apr 2014
Posts: 74
Likes: 1
In that case; It is possible for you to have an exhaust leak in bank1, making the sensor read lean and making bank 1 rich. Just an idea. When you are in open loop you're just operating on VE or MAF, trims stop.
Thread Starter
Teching In
Joined: Feb 2017
Posts: 6
Likes: 0
I don’t know what’s going on now.
I get
P015B
P015D
P219A
P219B
now. I wonder if this batch of o2 sensors is just ****. I didn’t get any CEL before I changed them. However I bought new ones (NTK) to remedy the closed loop poor performance problem.
Now i got new sensors - Problem Stil persists. But new CELs
i looged some sensor data (timing retard, o2 voltage o2 % st fuel trim, lt fuel trim and intake manifold pressure). It’s to big to upload as it’s a screen recording about 12 minutes long.
anybody have some baseline numbers what it should look like ?
no mods besides the CAI and ZL1 lid
thanks for any help
I get
P015B
P015D
P219A
P219B
now. I wonder if this batch of o2 sensors is just ****. I didn’t get any CEL before I changed them. However I bought new ones (NTK) to remedy the closed loop poor performance problem.
Now i got new sensors - Problem Stil persists. But new CELs
i looged some sensor data (timing retard, o2 voltage o2 % st fuel trim, lt fuel trim and intake manifold pressure). It’s to big to upload as it’s a screen recording about 12 minutes long.
anybody have some baseline numbers what it should look like ?
no mods besides the CAI and ZL1 lid
thanks for any help
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