Closed loop faulty? - Mustang Evolution

Go Back   Mustang Evolution > Shelby | ROUSH | Boss | Saleen | SVT || Tech and Talk > SVT Mustang



Reply
 
Thread Tools Search this Thread
Please support our sponsors and let them know you heard about them here!
Old 06-11-2013, 05:27 PM   #1
Registered Member
Regular
 
94 GT 5.0's Avatar
 
Join Date: Mar 2013
Location: SF
Region: California
Posts: 221
Closed loop faulty?

Im confused to what this is? Can somebody please explain
94 GT 5.0 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 06-22-2013, 03:34 PM   #2
Registered Member
Regular
 
540i6e39's Avatar
 
Join Date: Jun 2013
Location: Sacramento
Region: California
Posts: 155
Quote:
Originally Posted by 94 GT 5.0 View Post
Im confused to what this is? Can somebody please explain
When the engine is first started, and rpm is above 400 rpm, the system goes into 'Open Loop' operation. In 'Open Loop', the ECM will ignore the signal from the Oxygen (O2) sensor and calculate the air/fuel ratio based on inputs from the coolant and MAF sensors, but mostly from a pre-programmed table in the memcal.The system will stay in 'Open Loop' until the following conditions are met:1. The O2 sensor has varying voltage output, showing that it is hot enough to operate properly. (This depends on temperature)*2. The coolant sensor is above a specified temperature about 40oC/104oF.*3. A specific amount of time has elapsed after starting the engine.The specific values for the above conditions vary with different engines and are stored in the mem-cal. When these conditions are met, the system goes into 'Closed Loop' operation. In 'Closed Loop', the ECM will calculate the air/fuel ratio (injector on-time) based on the various sensors but mainly the O2 sensor. This allows the air/fuel ratio to stay very close to 14.7:1.

I copied and pasted this but its simple. When you cold start your car the secondary air pump turns on till the car is warmed up and is in open loop which means the ecu isn't controlling anything. When the car warms up it switches to closed loop and the ecu is in control of everything. Also when you go wot it switches back to open loop I believe.
540i6e39 is offline   Reply With Quote
Old 06-24-2013, 04:34 PM   #3
Registered Member
Regular
 
94 GT 5.0's Avatar
 
Join Date: Mar 2013
Location: SF
Region: California
Posts: 221
Quote:
Originally Posted by 540i6e39 View Post

When the engine is first started, and rpm is above 400 rpm, the system goes into 'Open Loop' operation. In 'Open Loop', the ECM will ignore the signal from the Oxygen (O2) sensor and calculate the air/fuel ratio based on inputs from the coolant and MAF sensors, but mostly from a pre-programmed table in the memcal.The system will stay in 'Open Loop' until the following conditions are met:1. The O2 sensor has varying voltage output, showing that it is hot enough to operate properly. (This depends on temperature)*2. The coolant sensor is above a specified temperature about 40oC/104oF.*3. A specific amount of time has elapsed after starting the engine.The specific values for the above conditions vary with different engines and are stored in the mem-cal. When these conditions are met, the system goes into 'Closed Loop' operation. In 'Closed Loop', the ECM will calculate the air/fuel ratio (injector on-time) based on the various sensors but mainly the O2 sensor. This allows the air/fuel ratio to stay very close to 14.7:1.

I copied and pasted this but its simple. When you cold start your car the secondary air pump turns on till the car is warmed up and is in open loop which means the ecu isn't controlling anything. When the car warms up it switches to closed loop and the ecu is in control of everything. Also when you go wot it switches back to open loop I believe.
Awesome thanks man. What could go faulty on it though? Because my 97 is throwing a code saying i'm running lean then it shows closed loop fault. Could it still have to do with my O2's?
94 GT 5.0 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 06-24-2013, 05:19 PM   #4
Registered Member
Regular
 
540i6e39's Avatar
 
Join Date: Jun 2013
Location: Sacramento
Region: California
Posts: 155
Quote:
Originally Posted by 94 GT 5.0 View Post

Awesome thanks man. What could go faulty on it though? Because my 97 is throwing a code saying i'm running lean then it shows closed loop fault. Could it still have to do with my O2's?
bad O2,
Or a bad catalytic converter
540i6e39 is offline   Reply With Quote
Old 06-25-2013, 03:06 AM   #5
Registered Member
Regular
 
94 GT 5.0's Avatar
 
Join Date: Mar 2013
Location: SF
Region: California
Posts: 221
Quote:
Originally Posted by 540i6e39 View Post
bad O2,
Or a bad catalytic converter
I really hope it's not the cats
94 GT 5.0 is offline   Reply With Quote
Old 06-25-2013, 06:58 AM   #6
Registered Member
Regular
 
540i6e39's Avatar
 
Join Date: Jun 2013
Location: Sacramento
Region: California
Posts: 155
Quote:
Originally Posted by 94 GT 5.0 View Post

I really hope it's not the cats
Go down to your local muffler shop and you could probably get magnaflow highflow cats for 150 each. Thats what I get them for in the bay area or check craigslist.
540i6e39 is offline   Reply With Quote
Old 06-28-2013, 08:54 PM   #7
Registered Member
Regular
 
94 GT 5.0's Avatar
 
Join Date: Mar 2013
Location: SF
Region: California
Posts: 221
Quote:
Originally Posted by 540i6e39 View Post

Go down to your local muffler shop and you could probably get magnaflow highflow cats for 150 each. Thats what I get them for in the bay area or check craigslist.
But will they let me pass smog?
94 GT 5.0 is offline   Reply With Quote
Old 01-22-2014, 12:21 PM   #8
Registered Member
Regular
 
94 GT 5.0's Avatar
 
Join Date: Mar 2013
Location: SF
Region: California
Posts: 221
I forgot to update I replaced all 4 o2's and got rid of the code, got rid of missfires as well. I went to get my cats checked out and found out only the shells are welded on, both actual cat's arent there. I guess that's good since I have straight pipes. But not good cause now I need to pay 300 to pass smog checks.
94 GT 5.0 is offline   Reply With Quote
Reply

Lower Navigation
Go Back   Mustang Evolution > Shelby | ROUSH | Boss | Saleen | SVT || Tech and Talk > SVT Mustang

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


» Like Us On Facebook



12:47 PM


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0

MustangEvolution.com is in no way associated with or endorsed by Ford Motor Company.