Everyone with SD tune issue: VERY lean on starts after certain time delay.
07-15-2006, 10:01 AM
#104
Same here...I've had the problem with the MAF plugged in and tuned out, as well as completely removed from the car. The bias filter seems to have band-aided it enough for me to work with, although my car wasn't particularly bad with this problem to begin with.
07-15-2006, 01:48 PM
#105
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Same thing on my car. It has the lean on cold start issue, although not very bad or for very long. The lean on warm restart that goes away after 2K. I've been playing with the airflow tables to see if that was it on the cold start. I'll keep messing with it and post results as I go.
08-25-2006, 01:57 PM
#108
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Check your logs. When you see this lean idle are you in open or closed loop at the time?
True cold-start or start-up enrichment only lasts for a few seconds, so I'm sure that's not where your problem is.
Though it may be labeled differently in different year tunes, each code will have a table that adjusts your air-fuel ratio based on coolant temp. Some tunes call this the OLFA. This table is not all or even partially zero'd from the factory. This table adds fuel for lower coolant temps for a reason.
I believe the values in this table is your base fueling (not your base AFR). If this table isn't correct, then any corrections being applied will be very far off the mark when watching your WBO2.
True cold-start or start-up enrichment only lasts for a few seconds, so I'm sure that's not where your problem is.
Though it may be labeled differently in different year tunes, each code will have a table that adjusts your air-fuel ratio based on coolant temp. Some tunes call this the OLFA. This table is not all or even partially zero'd from the factory. This table adds fuel for lower coolant temps for a reason.
I believe the values in this table is your base fueling (not your base AFR). If this table isn't correct, then any corrections being applied will be very far off the mark when watching your WBO2.
08-25-2006, 03:25 PM
#109
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Originally Posted by WS6FirebirdTA00
That is nto the issue, for me at least. I zeroed out all thsi stuff and it has a small effect, but the main cause of the issue is a heat soaked IAT as well as poor calculations based on IAT, IMO
If you didn't filter out low ECT's you likely collected enough normal operating temp data to average out the low ECT effect.
Double check the link above and scroll down a bit to the screen shots I posted.
08-25-2006, 05:55 PM
#112
mine is lean on start up but only when cold,not warm,afr is about 17.2 for about 3 minutes then runs good,also just started throwing misfire codes so i changed the plugs and wires with no improvement.i raced all summer and never a problem now its a problem?what gives
08-25-2006, 06:52 PM
#113
Originally Posted by TAQuickness
I believe it's B3605 on the non MAP vs RPM OS's. It's B3647 in OS3 and OS5.
That must be some efi live stuff. It doesn't look like anything I have seen in LS1 edit or HP tuners. Do you have an english version.
08-25-2006, 07:22 PM
#114
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Originally Posted by 30thta436
That must be some efi live stuff. It doesn't look like anything I have seen in LS1 edit or HP tuners. Do you have an english version.
http://www.efilive.com/download.aspx
08-26-2006, 08:37 AM
#116
Well, I put extra fuel in there on startup, I have tried just about everything. No matter what though, until the car is running for a little bit it will read lean, and it really shows up when frist driving. I have set the IAC motor below where it normally is for hot idle, and as long as the IAT is not heat soaked that helps the issue out, for idle. Still doesnt solve the problems going down the road.
The way the comptuer adjusts for hot starts or change in temp is through the IAC motor anyway, thats why I think there are other things going on in the computer and its calculations that we just dont see. This isnt as big of an issue on the newer OS as I know a few guys who cleared this issue up a few months back, but the older OS is still an issue.
The way the comptuer adjusts for hot starts or change in temp is through the IAC motor anyway, thats why I think there are other things going on in the computer and its calculations that we just dont see. This isnt as big of an issue on the newer OS as I know a few guys who cleared this issue up a few months back, but the older OS is still an issue.
08-26-2006, 08:39 AM
#117
Originally Posted by white2001s10
Check your logs. When you see this lean idle are you in open or closed loop at the time?
True cold-start or start-up enrichment only lasts for a few seconds, so I'm sure that's not where your problem is.
Though it may be labeled differently in different year tunes, each code will have a table that adjusts your air-fuel ratio based on coolant temp. Some tunes call this the OLFA. This table is not all or even partially zero'd from the factory. This table adds fuel for lower coolant temps for a reason.
I believe the values in this table is your base fueling (not your base AFR). If this table isn't correct, then any corrections being applied will be very far off the mark when watching your WBO2.
True cold-start or start-up enrichment only lasts for a few seconds, so I'm sure that's not where your problem is.
Though it may be labeled differently in different year tunes, each code will have a table that adjusts your air-fuel ratio based on coolant temp. Some tunes call this the OLFA. This table is not all or even partially zero'd from the factory. This table adds fuel for lower coolant temps for a reason.
I believe the values in this table is your base fueling (not your base AFR). If this table isn't correct, then any corrections being applied will be very far off the mark when watching your WBO2.
The OLFA shouldnt be zeroed anyway, and yes it adds fuel to colder ECTs for a reason.
08-26-2006, 08:45 AM
#118
Originally Posted by TAQuickness
zeroing out is not what i had in mind. You would want to add more fuel to compensate for the start up airflows. Recall, that as ECT goes down, your RAF table adds more air to maintain idle. If you dialed in your VE table filtering out low ECT's none of then startup air or low ECT RAF air is accounted for.
If you didn't filter out low ECT's you likely collected enough normal operating temp data to average out the low ECT effect.
Double check the link above and scroll down a bit to the screen shots I posted.
If you didn't filter out low ECT's you likely collected enough normal operating temp data to average out the low ECT effect.
Double check the link above and scroll down a bit to the screen shots I posted.
If you tuned the car using lower ECTs when the car is not fully warm your tune will be screwy and not have consistent fueling (at least inwhat I have seen). Since my car is OLSD I always tune it in my operating range. I think its foolish to do otherwise because the airflow varies and can result in an inaccurate VE or MAF table. I use the startup parameters that we have and that helps with some of the correction, and the idle isnt bad, but the first mile I drive on the street is in certain low flow spots. I dont want to add 15% fuel to here to bandaid a problem and then be rich after that mile. I have my theory on this stuff, and I dont think it can be correctly solved unless we can alter some of the ways the computer calculates the airflow vs air temps as well as airflow vs startup conditions.
08-26-2006, 07:15 PM
#119
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Originally Posted by WS6FirebirdTA00
If you tuned the car using lower ECTs when the car is not fully warm your tune will be screwy and not have consistent fueling (at least inwhat I have seen). Since my car is OLSD I always tune it in my operating range. I think its foolish to do otherwise because the airflow varies and can result in an inaccurate VE or MAF table.
Originally Posted by WS6FirebirdTA00
I use the startup parameters that we have and that helps with some of the correction, and the idle isnt bad, but the first mile I drive on the street is in certain low flow spots. I dont want to add 15% fuel to here to bandaid a problem and then be rich after that mile. I have my theory on this stuff, and I dont think it can be correctly solved unless we can alter some of the ways the computer calculates the airflow vs air temps as well as airflow vs startup conditions.
I think in so many words you have said the same thing I have. It's the extra air present during off normal operating temps causing the problem. MAF guys don't see the problem as pronounced because the MAF table is a much higher resolution than the VE with IAT adjustments built in (nature of the beast).
By using tables available in OEM OS's, and otherwise zeroed from the factory, we can compensate for these lean conditions until we reach normal operating temp.
From what I gather though, it sounds as if you may be chasing 2 or more problems.
