Leaning out OL to avoid smell
03-09-2011, 01:18 PM
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Leaning out OL to avoid smell I posted this on another site but i thought I'd put it here too.
What is the safest I can lean out my OL tables? On startup the exhaust smell is pretty strong and the wideband reads an afr in the 10s.
I'm moving into a new private garage and don't want the startup exhaust smell to be a problem for the tenants above. I figure if I lean out the OL tables it would smell less.
Do you think if i make the lowest OL afr target 12.5 the car would still start without problems even in cold weather?
Also on a seperate note the car sometimes begins to stall or completely stalls out when i put it in reverse especially if i have the steering wheel turned. do you know what table can help me fix that?
What is the safest I can lean out my OL tables? On startup the exhaust smell is pretty strong and the wideband reads an afr in the 10s.
I'm moving into a new private garage and don't want the startup exhaust smell to be a problem for the tenants above. I figure if I lean out the OL tables it would smell less.
Do you think if i make the lowest OL afr target 12.5 the car would still start without problems even in cold weather?
Also on a seperate note the car sometimes begins to stall or completely stalls out when i put it in reverse especially if i have the steering wheel turned. do you know what table can help me fix that?
03-09-2011, 03:41 PM
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It shouldnt be any where near there. it should be in the 14's or 15's if your just idling. maybe a little more rich if its cold. wot throt. n/a should be around 13 or 12.9afrs. in boost 12-11.9afrs. This is just a ballpark figure. I'm supprised your not pouring out black smoke if your running 10's at idle. your going to wash the bottom end out with all that fuel. thats your stalling issue.
03-09-2011, 08:42 PM
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i'm talking about initial startup before its in closed loop where you would normally see stoich. those values i'm seeing are the stock values GM set in the open loop tables which are used on initial startup.
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03-10-2011, 10:21 PM
#9
The best way is to first tune your VE and MAF tables, but it's going to be a little tricky.
If you dont want the trouble of tuning them, lean out the OL tables until you reach high 13's. If the VE and MAF are not calibrated properly, the commanded AFR in the OL tables won't be the same you'll see with the wideband, but it doesn't matter.
You need to find the AFR your engine likes the most. Some cars idle cold with AFR of 14's or 15's with no problem, other cars have trouble
It can be done, just don't lean it too much
If you dont want the trouble of tuning them, lean out the OL tables until you reach high 13's. If the VE and MAF are not calibrated properly, the commanded AFR in the OL tables won't be the same you'll see with the wideband, but it doesn't matter.
You need to find the AFR your engine likes the most. Some cars idle cold with AFR of 14's or 15's with no problem, other cars have trouble
It can be done, just don't lean it too much
03-11-2011, 06:36 AM
#11
The best way is to first tune your VE and MAF tables, but it's going to be a little tricky.
If you dont want the trouble of tuning them, lean out the OL tables until you reach high 13's. If the VE and MAF are not calibrated properly, the commanded AFR in the OL tables won't be the same you'll see with the wideband, but it doesn't matter.
You need to find the AFR your engine likes the most. Some cars idle cold with AFR of 14's or 15's with no problem, other cars have trouble
It can be done, just don't lean it too much
If you dont want the trouble of tuning them, lean out the OL tables until you reach high 13's. If the VE and MAF are not calibrated properly, the commanded AFR in the OL tables won't be the same you'll see with the wideband, but it doesn't matter.
You need to find the AFR your engine likes the most. Some cars idle cold with AFR of 14's or 15's with no problem, other cars have trouble
It can be done, just don't lean it too much
You can try to lean out the car in the adder table if it has one until it want to stall and then go back and add some. Your Wide-Band's AFR seem too rich, but with your setup it may not idle unless it is that rich.
Last edited by CalEditor; 03-11-2011 at 06:44 AM.
03-11-2011, 09:03 AM
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my ve tables definitely need to be tuned again. motor was down a cylinder so it was running lean while i was tuning it. got a new block so i need to retune since its too rich now. i'm working on it just need to find the time. still i think th OL table is set way too rich from the factory especially in the colder temp ranges.
as far as the smell the cam and removal of certain
items don't help.
hey brad nice avatar. you put thoes TTMs on the car yet?
as far as the smell the cam and removal of certain
items don't help.hey brad nice avatar. you put thoes TTMs on the car yet?
03-11-2011, 11:36 AM
#13
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The wideband reads lambda and converts that to what is set for AFR.
Yeah C, TTMs are on.
Brad
03-11-2011, 12:51 PM
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There is a fair degree of cold-ECT open loop enrichment
in the stock LS1 tune. I expect the LT1 is somewhat
similar. The enrichment is compounded by a cam with
the VE table un-corrected, because it indicates more
air mass than is real anymore.
If your wideband reads near commanded, then you
want to change the commanded (to where the motor
still runs OK, but is leaner). If the two disagree then
you work on the airflow accuracy side.
Immediately after start you also have "afterstart
enrichment" which is additive to all of that.
in the stock LS1 tune. I expect the LT1 is somewhat
similar. The enrichment is compounded by a cam with
the VE table un-corrected, because it indicates more
air mass than is real anymore.
If your wideband reads near commanded, then you
want to change the commanded (to where the motor
still runs OK, but is leaner). If the two disagree then
you work on the airflow accuracy side.
Immediately after start you also have "afterstart
enrichment" which is additive to all of that.
03-11-2011, 10:28 PM
#17
This is an OBD 1.5 car. I have never looked at a tune for this type of car. I would have to say it is an adder table. ECT adder to richen the car when cold.
You can try to lean out the car in the adder table if it has one until it want to stall and then go back and add some. Your Wide-Band's AFR seem too rich, but with your setup it may not idle unless it is that rich.
You can try to lean out the car in the adder table if it has one until it want to stall and then go back and add some. Your Wide-Band's AFR seem too rich, but with your setup it may not idle unless it is that rich.
I had some cars with pig-rich idle at cold ECT (after cam and a few other mods). Modified the OL AFR tables and they were good, most of them liked AFRs at high 13's to idle properly and reach operating temperature fast.
If you don't want to mess with that table, you need to calibrate the MAF, because the VE tables have little to no effect at any ECT (unless you set speed density mode).
But most tuners suggest to leave MAF tables as they are, because it is very difficult to correctly tune them.
If the AFR is rich only at afterstart open loop, you can lean the OL tables and correct the problem. Is not the best way but it works.
As soon as the PCM enters CL those tables are not used anymore.
03-12-2011, 09:45 AM
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okay guys i need to modify my ve tables again definitely (i run sd mode). anyway logged the car for the first time and yes the left side is pig rich. prior tuning done with a dead cylinder so thats why its super rich. i'll get my ve tables in order and bump up my open loop tables. the log also let me know that my right O2 is on the way out so i have to replace that as well since closed loop is running super rich too. all this should help alleviate the smell.
03-12-2011, 07:38 PM
#20
Do you have a wideband? or are you tuning with BLM's ??
If you are using BLM to tune your VE tables, I suggest you buy 2 new O2 sensors to properly calibrate VE tables.
If you are using BLM to tune your VE tables, I suggest you buy 2 new O2 sensors to properly calibrate VE tables.