Going super lean on cold start - Tuning Forum

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Going super lean on cold start
Saturday, November 20, 2010 6:33 PM
Ok so I'm having a weird issue with the tune on my S/C eco caviler. The car goes super lean (like beyond the 20:1 the lc1 can read) on cold startup and it also now goes that lean on all startup, then after the normal closed loop delay (even with closed loop disabled, I know there is a value in the computer somewhere for closed loop delay.) After that first minute or so it goes down to cruising at 14-15:1 and idling at like 10:1ish. The closer I get idle and cruising tuned the worse it gets. What the heck is going on? is there something I'm missing here? Or am I just missing a table?


Also, I noticed this was weird as well. Sometimes when I'm tuning the car just decides it wants to make the non-pe cmd afr stupid values like 13.2:1 and 12.6:1. It just does it and it wont go away unless I shut off the car and let it sit a bit, or reflash. It never does this when closed loop is enabled.

My tune is attached to my thread on hpt forums found here.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer

Re: Going super lean on cold start
Saturday, November 20, 2010 8:10 PM
Excuse me if I'm mistaken, but doesn't the O2 sensor need to warm up first before it'll get an accurate reading?

Hell, my NB will barely read the lean side for a few minutes after a cold start.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick
Re: Going super lean on cold start
Saturday, November 20, 2010 8:53 PM
When was the last time you did a free air calibration?





P&P Tuning
420.5whp / 359.8wtq

Re: Going super lean on cold start
Saturday, November 20, 2010 9:40 PM
QWK LN2 (P&P Tuning) wrote:When was the last time you did a free air calibration?


When I first put the sensor in at the end of the summer, about 2000 miles ago.

And the wideband does need time to warm up. But when I was checking this to see how startup afr's were I was letting the sensor warm with the key in the on position then starting the car, I know not the best thing for it but I want/needed the data. And the lean condition lasts long enough that even starting with the wideband cold it is still present.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Going super lean on cold start
Saturday, November 20, 2010 10:21 PM
Leafy wrote:
QWK LN2 (P&P Tuning) wrote:When was the last time you did a free air calibration?


When I first put the sensor in at the end of the summer, about 2000 miles ago.

And the wideband does need time to warm up. But when I was checking this to see how startup afr's were I was letting the sensor warm with the key in the on position then starting the car, I know not the best thing for it but I want/needed the data. And the lean condition lasts long enough that even starting with the wideband cold it is still present.
Check your thread on HPT Forums...





P&P Tuning
420.5whp / 359.8wtq

Re: Going super lean on cold start
Saturday, November 20, 2010 10:21 PM
Just did.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Going super lean on cold start
Sunday, November 28, 2010 12:40 PM
Ok well, went back to an old tune with closed loop enabled. first time I started it with this tune it did the super lean thing again to the point where the first minute or two of driving the car is almost stalling as I'm driving. But after the first time I ran it with that tune it was fine. This is so weird. I dont think I'm going to mess with this thing very much more until my fuel pressure gauge comes.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Going super lean on cold start
Saturday, December 04, 2010 12:45 PM
I have the oposite problems mine starts pig rich. Once the closed loop enables its fine. Damn idle issues with these cars drive me nuts.



Re: Going super lean on cold start
Saturday, December 04, 2010 3:24 PM
my car ran super pig rich to the point it would kill itself if you touched the pedal and foul the plugs out. my solution was to up the idle. worked great


running rich? turn the boost up
Re: Going super lean on cold start
Saturday, December 04, 2010 8:59 PM
Funny. how rich is super pig rich for you guys? My car is perfectly content with idling at 8:1 and will drive just fine that way.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Going super lean on cold start
Sunday, December 05, 2010 11:54 AM
Leafy wrote:Funny. how rich is super pig rich for you guys? My car is perfectly content with idling at 8:1 and will drive just fine that way.
I feel sorry for your engine........





P&P Tuning
420.5whp / 359.8wtq


Re: Going super lean on cold start
Sunday, December 05, 2010 11:58 AM
like 10-1 for me, i know its not right but the driving afrs are ok.



Re: Going super lean on cold start
Sunday, December 05, 2010 12:16 PM
QWK LN2 (P&P Tuning) wrote:
Leafy wrote:Funny. how rich is super pig rich for you guys? My car is perfectly content with idling at 8:1 and will drive just fine that way.
I feel sorry for your engine........


Don't feel bad it ran with that tune for about 20 minutes and got an oil change 200 miles later.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Going super lean on cold start
Sunday, December 05, 2010 2:28 PM
yeah 8:1 is way way way to rich i'd say your rings dont like you now as well...



Re: Going super lean on cold start
Sunday, December 05, 2010 4:03 PM
eh, it was just a good top engine cleaning. Now I dont burn any oil any more when I did a bit cause of rings before it went that rich the first time I started it with the blower.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
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