Everyone with SD tune issue: VERY lean on starts after certain time delay.
03-30-2006, 09:29 PM
#41
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Originally Posted by Haans249
LOL, good luck getting your car to even run. It'll most likely rev super high if you unplug it.
Adrian
Adrian
I guess you have no idea how many people run every day with it unplugged.
03-31-2006, 01:18 AM
#44
i think the lean condition is caused by some ve multiplier i dont have access to. i set my iac motor to 25 steps, hot idle is 35 steps, and the car is still way lean on me. I just think its something weird going on where the car thinks incomming air is hotter from being heat soaked. i have ruled out IAT as a culprit as well.
03-31-2006, 05:19 AM
#45
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would spark affect it at all? pulling some or adding in that area to see if anything changes? im sure its been mentioned, just didnt feel like reading all the posts :p
03-31-2006, 08:27 AM
#46
Basically, what this comes down to is that people just aren't comprehending the problem. This isn't some random, always there issue. It only happens after the car has been off for a certain amount of time, and only for a certain amount of time after the car has been restarted (~3 minutes). The parameters listed earlier in this thread only last for a couple of seconds at most, as they decay by crankshaft/camshaft revolutions, not seconds.
We are seeing something that is affected by a timer of some sort that is only active in SD, but not with the MAF running.
It has nothing to do with timing, and nothing to do with startup airflow/fueling.
We are seeing something that is affected by a timer of some sort that is only active in SD, but not with the MAF running.
It has nothing to do with timing, and nothing to do with startup airflow/fueling.
03-31-2006, 08:38 AM
#48
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I am wondering why any amount of IAC, idle airflow matters
to fueling. The air should still be attended by adequate fuel,
according to your commanded fual air multiplier. Do you see
this going way lean at the time, or is it that the mixture is
diverging from the commanded point? I think this is the nut
of it.
to fueling. The air should still be attended by adequate fuel,
according to your commanded fual air multiplier. Do you see
this going way lean at the time, or is it that the mixture is
diverging from the commanded point? I think this is the nut
of it.
03-31-2006, 09:33 AM
#50
i think a small change in airflow like Steve is seeing could be iac related because on start up the iac motor on my car at least is arond 70 steps and hot idle works down to 35, i can see that because it will change the airflow about a point
on my car it is so damn lean that this doesnt even matter. i mean i am anywhere from 3-6 point lean on start up. and yes this issue has always been there just couldnt figure it out until i had the wb
on my car it is so damn lean that this doesnt even matter. i mean i am anywhere from 3-6 point lean on start up. and yes this issue has always been there just couldnt figure it out until i had the wb
03-31-2006, 09:35 AM
#51
Originally Posted by WS6FirebirdTA00
i think a small change in airflow like Steve is seeing could be iac related because on start up the iac motor on my car at least is arond 70 steps and hot idle works down to 35, i can see that because it will change the airflow about a point
on my car it is so damn lean that this doesnt even matter. i mean i am anywhere from 3-6 point lean on start up. and yes this issue has always been there just couldnt figure it out until i had the wb
on my car it is so damn lean that this doesnt even matter. i mean i am anywhere from 3-6 point lean on start up. and yes this issue has always been there just couldnt figure it out until i had the wb
03-31-2006, 11:31 AM
#52
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But is it the commanded that's whacked, or the actual
diverging from it?
Wonder if IAT heat soak / discrepancy might be in the
mix. That is a time-varying component of the speed
density calculation and might take some time to get
in line with the in-taken air (or if it's just flapping, be
a variable error term decoupled from true air). The
timescale for IAT to come around to reality can be long
at low airflows. The air mass from air volume*pressure
needs temperature to calculate (PV=nRt, n being molar
mass, etc.).
diverging from it?
Wonder if IAT heat soak / discrepancy might be in the
mix. That is a time-varying component of the speed
density calculation and might take some time to get
in line with the in-taken air (or if it's just flapping, be
a variable error term decoupled from true air). The
timescale for IAT to come around to reality can be long
at low airflows. The air mass from air volume*pressure
needs temperature to calculate (PV=nRt, n being molar
mass, etc.).
03-31-2006, 11:33 AM
#53
iat has nothign to do with it either, ruled that one out as i had the iat up to like 110* when it was 70 out and the car ran fine and i can put the iat in a cup of ice while its running and it wont do anything.
Steve, its the start up airflow parameters there were mentioned earlier, like start up friction airflow.
Jimmy, i have a post on hpt with a log. commanded will be like 13.7:1 and actual shows like 16.8:1. commanded is where i want it and actual is way lean
Steve, its the start up airflow parameters there were mentioned earlier, like start up friction airflow.
Jimmy, i have a post on hpt with a log. commanded will be like 13.7:1 and actual shows like 16.8:1. commanded is where i want it and actual is way lean
03-31-2006, 12:20 PM
#54
Originally Posted by WS6FirebirdTA00
Steve, its the start up airflow parameters there were mentioned earlier, like start up friction airflow.
03-31-2006, 12:29 PM
#55
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Correct me if I'm wrong, but a leaner mix = hotter exhuast right?
EPA demands cat's start functioning as soon as possible right?
Car sits for a few minutes (3 or so) and even though the motor is still pretty warm, the cats have had time to cool significantly.
Seems like if there is a table missing, it might have something to do with cat light off.
dunno. just thinking out loud.
EPA demands cat's start functioning as soon as possible right?
Car sits for a few minutes (3 or so) and even though the motor is still pretty warm, the cats have had time to cool significantly.
Seems like if there is a table missing, it might have something to do with cat light off.
dunno. just thinking out loud.
03-31-2006, 12:44 PM
#56
Originally Posted by TAQuickness
Correct me if I'm wrong, but a leaner mix = hotter exhuast right?
EPA demands cat's start functioning as soon as possible right?
Car sits for a few minutes (3 or so) and even though the motor is still pretty warm, the cats have had time to cool significantly.
Seems like if there is a table missing, it might have something to do with cat light off.
dunno. just thinking out loud.
EPA demands cat's start functioning as soon as possible right?
Car sits for a few minutes (3 or so) and even though the motor is still pretty warm, the cats have had time to cool significantly.
Seems like if there is a table missing, it might have something to do with cat light off.
dunno. just thinking out loud.
03-31-2006, 01:00 PM
#57
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could be part of the whole SD is a backup for the MAF thing. Say the MAF fails, you default to an SD tune, PCM leans you out on start up to light off the cats and heat up the NB's so you can limp to the dealer for a new MAF.
Again just speculating. I can make all kinds of **** work on paper.
Again just speculating. I can make all kinds of **** work on paper.
03-31-2006, 01:02 PM
#58
Originally Posted by TAQuickness
could be part of the whole SD is a backup for the MAF thing. Say the MAF fails, you default to an SD tune, PCM leans you out on start up to light off the cats and heat up the NB's so you can limp to the dealer for a new MAF.
Again just speculating. I can make all kinds of **** work on paper.
Again just speculating. I can make all kinds of **** work on paper.
03-31-2006, 01:55 PM
#59
I dont have a WBO2 but I am pretty sure that I am having the same problem. I am a complete noob to tuning and my first wack at this has been by dialing in an LS2 402 in a 98 Z28 M6. Talk about jumping into the deep end with 50 lb cement shoes.
I just think that I am having the same problem because I have the idle and the VE tables dialed in perfect and after I stop and shut the car off for like 15 min and then start it back up, it runs kinda rough for about 3 min or so and then it's good again.
I just think that I am having the same problem because I have the idle and the VE tables dialed in perfect and after I stop and shut the car off for like 15 min and then start it back up, it runs kinda rough for about 3 min or so and then it's good again.
03-31-2006, 02:00 PM
#60
Originally Posted by 98Z28CobraKiller
I dont have a WBO2 but I am pretty sure that I am having the same problem. I am a complete noob to tuning and my first wack at this has been by dialing in an LS2 402 in a 98 Z28 M6. Talk about jumping into the deep end with 50 lb cement shoes.
I just think that I am having the same problem because I have the idle and the VE tables dialed in perfect and after I stop and shut the car off for like 15 min and then start it back up, it runs kinda rough for about 3 min or so and then it's good again.
I just think that I am having the same problem because I have the idle and the VE tables dialed in perfect and after I stop and shut the car off for like 15 min and then start it back up, it runs kinda rough for about 3 min or so and then it's good again.
I just hate that no one can figure this one out...