SR20ve low timing at idle? - SR20 Forum
 
Thread Tools
#1 (permalink) Old 05-28-2009, 05:10 PM
SE-R Monster
 
Join Date: Apr 2003
Location: New York
Posts: 661
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 6 reviews
(Thread Starter)
SR20ve low timing at idle?

OK well i have a VE setup running off a calum basic board and i am in the initial stages of tunning it. at idle i have some slight issues. first off after a few seconds usually 5-10 the stock o2 sensor hits about .83-.85 and sits there the afr drops slightly from 14.7-.15.1 down to 13.9-14.1 at about the same time the ignition timing drops from 15 at the ecu side down to 7-11 deg. i have the actual base timing set to 15 deg confirmed by timing light. so i am not sure what i should do as timing and AFR maps show the correct values but it looks like the ecu pulls some other info after the car sits at idle in neutral for a few seconds.

2k2 aztec red specv (i/h/e/p/mm)(sold)
92 classic with mods (dismantled)
94 classic rare blue (totaled rearend hit)
91 Black (whole lotta attitude )
My true loves
http://www.sr20forum.com/turbo/158047-my-sleeper-p.html
mr.sentra_specv is offline  
Sponsored Links
Advertisement
 
#2 (permalink) Old 05-29-2009, 06:26 AM
SE-R Nut
 
Join Date: Apr 2002
Location: Frederick, Maryland
Posts: 1,268
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 17 reviews
Quote:
Originally Posted by mr.sentra_specv View Post
OK well i have a VE setup running off a calum basic board and i am in the initial stages of tunning it. at idle i have some slight issues. first off after a few seconds usually 5-10 the stock o2 sensor hits about .83-.85 and sits there the afr drops slightly from 14.7-.15.1 down to 13.9-14.1 at about the same time the ignition timing drops from 15 at the ecu side down to 7-11 deg. i have the actual base timing set to 15 deg confirmed by timing light. so i am not sure what i should do as timing and AFR maps show the correct values but it looks like the ecu pulls some other info after the car sits at idle in neutral for a few seconds.
I don't see anything to be concerned about in your description of how your car is behaving.

Both my cars (B13 DE and VE) also demonstrate this change in idle AFR, but mine do it after 20 to 30 seconds. The AFR richens a point or two -- it's very predictable, and it happens with Calum, JWT, and B13 OEM ECUs. In the DE, it seems to be associated with activation of the AIV, so my hypothesis has been that there is some residual trigger that has been carried forward in the Calum and JWT ECUs like some bad DNA. Nothing to worry about, and I don't know how to fix it.

Many times at idle, the narrow band will read either rich or lean for extended periods of time. Hold the RPM at 2500 to 3000 and observe the behavior of the narrow band O2 sensor read out. It should flip back and forth, rich to lean, every couple seconds. If it does, you are good to go. If it does not, then your mixture is way off or your O2 sensor is not working properly. All of this assumes that your ECU is set up for closed loop operation.

Setting your timing to 15* -- both physically and in the ECU just means that this is where the ECU starts from when it comes to idle timing. Unless you are in Set Timing Mode, the ECU will constantly adjust timing and AAR settings to keep your idle speed close to spec. If you put the car in Set Timing Mode, your timing will read 15* on your computer regardless of the physical setting (which you have to set with a timing light) and it will be rock steady.

Here endeth another overly long post -- hope it's helpful. Please respond if I have missed something.

Billc
billc is offline  
#3 (permalink) Old 05-29-2009, 08:50 AM
SE-R Monster
 
Join Date: Apr 2003
Location: New York
Posts: 661
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 6 reviews
(Thread Starter)
yeah it basically does every thing else perfectly. the second i put my foot on the gas the o2 switches lean/rich and verified by the voltage. i was just hoping to be able to get the AFR a steady 14.7 at idle.

2k2 aztec red specv (i/h/e/p/mm)(sold)
92 classic with mods (dismantled)
94 classic rare blue (totaled rearend hit)
91 Black (whole lotta attitude )
My true loves
http://www.sr20forum.com/turbo/158047-my-sleeper-p.html
mr.sentra_specv is offline  
#4 (permalink) Old 05-29-2009, 12:10 PM
SE-R Nut
 
Join Date: Apr 2002
Location: Frederick, Maryland
Posts: 1,268
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 17 reviews
Quote:
Originally Posted by mr.sentra_specv View Post
yeah it basically does every thing else perfectly. the second i put my foot on the gas the o2 switches lean/rich and verified by the voltage. i was just hoping to be able to get the AFR a steady 14.7 at idle.
I don't know what others have experienced, but your car is doing what mine do.
billc is offline  
#5 (permalink) Old 05-29-2009, 01:33 PM
ClamSlut
 
Calum's Avatar
 
Join Date: Dec 2001
Location: Lubbock, TX
Posts: 5,043
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 26 reviews
Bill- does it do this even when you unselect the O2 feedback bit?
Calum is offline  
#6 (permalink) Old 05-29-2009, 02:16 PM
SE-R Monster
 
Join Date: Apr 2003
Location: New York
Posts: 661
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 6 reviews
(Thread Starter)
i have a some what fix i tried this morning and it seems to work awesome. i was referencing some JDM stock bins and some sr20de stock bins and noticed that on the TPS closed timing table the ve bin i was using had 0 set from 60 degc-110c and the stock bins had 5 from 60c-110c so i changed this part of the bin. i also took 2 point off the top on the top 3 spots for the idle stabilization timing retard. the car now idles down to 15-18 deg timing and afr at idle stays around 14.4-14.7 on the wide band. those numbers are what my timing and afr maps are set to for the idle cell area.

2k2 aztec red specv (i/h/e/p/mm)(sold)
92 classic with mods (dismantled)
94 classic rare blue (totaled rearend hit)
91 Black (whole lotta attitude )
My true loves
http://www.sr20forum.com/turbo/158047-my-sleeper-p.html
mr.sentra_specv is offline  
#7 (permalink) Old 05-29-2009, 08:09 PM
SE-R Nut
 
Join Date: Apr 2002
Location: Frederick, Maryland
Posts: 1,268
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 17 reviews
Quote:
Originally Posted by Calum View Post
Bill- does it do this even when you unselect the O2 feedback bit?
I'm not sure -- will have to try it when I get a chance.
billc is offline  
Sponsored Links
Advertisement
 
 

  SR20 Forum > Vendor Customer Support > CalumSult (Archived for Informational Purposes)


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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 Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome