Open Loop and Closed Loop
Thread Starter
TECH Apprentice
Joined: Apr 2005
Posts: 319
Likes: 1
From: North Carolina
Open Loop and Closed Loop Can someone explain what closed and open loop mean in regard to O2 sensors?
I am having a horrible time keeping properly functioning O2's in my car since putting Hooker LT headers in. 3rd set of O2's in 3000 miles.
I am frying the upstream O2's and getting slow switching codes when SES light comes on.
Does anybody know how to get this right. I have heard a tune would fix it but how?
I am having a horrible time keeping properly functioning O2's in my car since putting Hooker LT headers in. 3rd set of O2's in 3000 miles.
I am frying the upstream O2's and getting slow switching codes when SES light comes on.
Does anybody know how to get this right. I have heard a tune would fix it but how?
OL == ignoring all O2 inputs
CL == taking O2's into consideration, building STFT and LTFTs and adjusting fueling based on these.
if you keep messing up your O2s, then you're either overfueling or they're too close to exhaust ports. if you dont have a tune (since you're asking about getting one) then i got my money on overfueling.
CL == taking O2's into consideration, building STFT and LTFTs and adjusting fueling based on these.
if you keep messing up your O2s, then you're either overfueling or they're too close to exhaust ports. if you dont have a tune (since you're asking about getting one) then i got my money on overfueling.
How do you have your exhaust system setup? Is it clamped or welded? I believe your overfueling is due to exhaust leaks. Sensor senses more air = adds more fuel. I bet your fuel trims are adding massive amounts of fuel.
Thread Starter
TECH Apprentice
Joined: Apr 2005
Posts: 319
Likes: 1
From: North Carolina
Originally Posted by Doc
How do you have your exhaust system setup? Is it clamped or welded? I believe your overfueling is due to exhaust leaks. Sensor senses more air = adds more fuel. I bet your fuel trims are adding massive amounts of fuel.
It is Hooker LT that have 3 bolt flanges. The flanges are welded. Then into dual Magnaflow high flow cats, into a custom Y. Then to the back to a Flowmaster 1 chamber racing muffler and stock tips. Its all welded and all in 3 inch pipe. There are no leaks. I thought there were but I did a careful check along with a muffler guy and its all kosher.
you don't 'get into' OL, it starts in it by default, so all you have to do is prevent the computer from going into CL.
if you want more on OL/CL read this:
http://redhardsupra.blogspot.com/200...-2-olvscl.html
if you want more on OL/CL read this:
http://redhardsupra.blogspot.com/200...-2-olvscl.html
