2.4L LE5 Performance Tech 16 valve 171 hp EcoTec with 163 lb-ft of torque

Diagnosing AFR Issue

Thread Tools
 
Search this Thread
 
Old 03-15-2013, 02:55 PM
  #1  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
Diagnosing AFR Issue

So to keep things simple and to the point I have an AFR issue only related to light throttle. AFR either goes pig rich or stupid lean 11afr or 17afr on light throttle.. Always a toss up and its one or the other. By monitoring dashhawk I noticed that without the issue happening the primary O2 sensor will read anywhere between 700mv-800mv. However, when the AFR freaks out the sensor will be reading very very low. Anywhere between 15mv-70mv which I imagine is a dead sensor. I'm not about to throw parts at the car unless I'm sure it's the issue. The car is maintained and other sensors such as the MAF are spotless.

Other odd note: doesn't happen above 46mph.

Also, does anyone know if on the bottom right corner of my Dashhawk means 'C' for Closed Loop and 'O' for Open Loop? Can't seem to find that answer anywhere. Even on MSD's website lol. Nor the manual.
Old 03-15-2013, 03:16 PM
  #2  
Rent me! per hour
 
Area47's Avatar
 
Join Date: 03-22-07
Location: Still fixing others mistakes.
Posts: 24,185
Likes: 0
Received 20 Likes on 14 Posts
watch the commanded afr and see what it does.
Old 03-15-2013, 03:54 PM
  #3  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
Ill try that next time. Will have to dig through the dashhawk to see if it reads it.
Old 03-15-2013, 05:21 PM
  #4  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
I saw 3 different commanded AFR #'s. The standard 14.7 which is normal. But it would either jump to 13.5 or 16.5 commanded randomly for some time. All at cruise under light throttle.
Old 03-15-2013, 05:27 PM
  #5  
Senior Member
iTrader: (1)
 
umrdyldo's Avatar
 
Join Date: 03-06-06
Location: MO
Posts: 11,666
Received 65 Likes on 59 Posts
i believe you correct about closed vs. open loop on the dashhawk
Old 03-15-2013, 05:34 PM
  #6  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
Wonder why it jumps from closed to open like that?
Old 03-15-2013, 05:49 PM
  #7  
Rent me! per hour
 
Area47's Avatar
 
Join Date: 03-22-07
Location: Still fixing others mistakes.
Posts: 24,185
Likes: 0
Received 20 Likes on 14 Posts
calibration issues
Old 03-15-2013, 10:21 PM
  #8  
Senior Member
iTrader: (6)
 
hhrfreek's Avatar
 
Join Date: 07-24-11
Location: WI
Posts: 1,068
Received 2 Likes on 2 Posts
Are you sure its mph and not rpm related? Are you entering open loop at a specific rpm?
Old 03-15-2013, 10:27 PM
  #9  
Senior Member
 
Sunburst_SS's Avatar
 
Join Date: 04-08-06
Location: Charlotte, NC
Posts: 2,397
Likes: 0
Received 3 Likes on 3 Posts
if for some reason your are hitting enough pressure from the turbo to trigger pe mode in your tune....which would make it go from closed loop to open loop......COT settings could change commaded fuel....
Old 03-16-2013, 02:22 PM
  #10  
Senior Member
iTrader: (17)
 
noorj's Avatar
 
Join Date: 09-03-10
Location: motor city
Posts: 2,750
Likes: 0
Received 0 Likes on 0 Posts
how far off are your fuel trims? I've seen commanded AFR change to swing the trims back in line.
Old 03-16-2013, 03:44 PM
  #11  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by hhrfreek
Are you sure its mph and not rpm related? Are you entering open loop at a specific rpm?
It feels like it's MPH related. Not sure how I could diagnose that? Open loop is always random and when it does this AFR issue happens. Only at light throttle from say 10mph to 46. I'm probably just gonna keep this between my tuner and I as this appears to be some sort of bug. I dont know much at all when it comes to the tuning aspect of it.

Originally Posted by noorjariri
how far off are your fuel trims? I've seen commanded AFR change to swing the trims back in line.
Wouldn't know as I do not have HP Tuners. Just gonna take it up with my tuner. No worries.

Last edited by Mindrot; 03-16-2013 at 03:44 PM. Reason: Automerged Doublepost
Old 03-16-2013, 10:07 PM
  #12  
Senior Member
iTrader: (6)
 
hhrfreek's Avatar
 
Join Date: 07-24-11
Location: WI
Posts: 1,068
Received 2 Likes on 2 Posts
Good idea he'll get ya squared away.
Old 03-18-2013, 03:37 PM
  #13  
Rent me! per hour
 
Area47's Avatar
 
Join Date: 03-22-07
Location: Still fixing others mistakes.
Posts: 24,185
Likes: 0
Received 20 Likes on 14 Posts
if the kpa trigger is set too low it will do this. {pe trigger} or the tps trigger is set wrong. set the cat test and rear o2 test to disable, and set the cot temps to stock, but disable the activity of it.
Old 03-18-2013, 06:29 PM
  #14  
Senior Member
Thread Starter
iTrader: (1)
 
Mindrot's Avatar
 
Join Date: 02-16-09
Location: Fredericksburg, VA
Posts: 3,207
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Area47
if the kpa trigger is set too low it will do this. {pe trigger} or the tps trigger is set wrong. set the cat test and rear o2 test to disable, and set the cot temps to stock, but disable the activity of it.
Thanks for the input. I appreciate it.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Solaris99
08-10 SS Turbocharged General Discussion
28
03-15-2017 01:22 PM
Trav3480
Problems/Service/Maintenance
0
10-01-2015 08:17 PM
Tupp
Suspension
5
09-30-2015 08:18 PM
yellow dragon
Problems/Service/Maintenance
0
09-28-2015 09:49 PM
SlowSaturn
Drivetrain
0
09-28-2015 11:03 AM



Quick Reply: Diagnosing AFR Issue



All times are GMT -4. The time now is 01:30 PM.