My car is lean in the morning

[wesam]

After tuning my VE table i noticed that the car is running lean at high weather temperature
and when drive it in the evening its running in the accepted range 14.6-14.8
but in the hot weather its running in the 15.5 range
what could i do in the tune to fix this issue
should i change the B4901 ?

[joecar]

wesam,

No, don't change B4901... that table models how IAT is influenced by ECT.

Post your .tun file and some logs.

[wesam]

This is the tune file and two logs log 41 is in hot temp
log 42 is in the same day but in the evening

[joecar]

I'm looking at those files, but I'm not sure yet...

41 is the hot temp log and it looks like it's running richer than commanded...

[wesam]

Joe the problem i used to see is when i check the Wide band map after a trip in ht weather it seems that all cells above the normal by one complete point (15.5 AFR )
but when i park the car and drive it in the evening at the same road at the same driving habits it seems that all cell going back to nearly 14.5-14.8 range

[WeathermanShawn]

You are running OLSD (Non-Custom OS) correct?

What temperature did you perform your AUTOVE? Was in on the street, or controlled ECT and IAT on a dyno?

On a street-tuned OLSD, a custom OS will address temperature bias, or just go CLSD. It will trim and you will never have to worry about it..of course that is all user preference. Just an opinion..

[joecar]

I see some things... as IAT increases the wideband AFR gets leaner...

Hmmm, might want to try AutoVE again, try to keep throttle more steady and open it progressively (i.e. not snapping it open), use the brakes to hold you back and to load the engine; be sure to apply the transient filter.

Just be sure to avoid or filter out any stoich cells in B3605.

[joecar]

This OS is 01250001/COS1 and it doesn't have many custom tables...

You might want to try 01250003/COS3 and have a play with table A0014 IAT VE Multiplier.

[WeathermanShawn]

I see some things... as IAT increases the wideband AFR gets leaner...

Hmmm, might want to try AutoVE again, try to keep throttle more steady and open it progressively (i.e. not snapping it open), use the brakes to hold you back and to load the engine; be sure to apply the transient filter.

Idle was always a problem for me when occasionally I tried OLSD (non-custom). Wow, with that IAT & ECT, that DYNAIRTMP would really be high! I think my record IAT has been 167F. OP, I see your IAT is way up there too?

Joe, is he Custom OS? Would that also take care of that heat soak?

[WeathermanShawn]

This OS is 01250001/COS1 and it doesn't have many custom tables...

You might want to try 01250003/COS3 and have a play with table A0014 IAT VE Multiplier.

Thanks for the clarification. Sorry I stepped on your response..:grin:

[joecar]

Thanks for the clarification. Sorry I stepped on your response..:grin:No problem, feel free to post what/when you like, this is all in the spirit of open discussion... :)

[joecar]

1250001 doesn't have A0014 and a few other tables.

Yes, IAT is going pretty high...

wesam, do you have a pic of your engine bay, and where are you located (generally)...?

[wesam]

I Don't have a heat soak problem i'm living in Middle east ( Qatar ) the temperature here is 40* C in the evening
so its normal to see such IAT
So how could i install a COS3 ? from where could i get it for my car 2004 Lumina SS ( GTO )

[stigmundfreud]

After going COS3 I returned to standard OS as whilst the temp blending can make things easier I found it more accurate to run stock OS and just autoVE at a regular constant IAT/AT also to keep things steady made sure the baro was always in a similar range. Thats not to say ignore COS3 but the message, as stated, is to tune in as regular situations as possible. If it isnt that easy then filter your logs based on a close IAT range, the ECU can then adjust based on a VE created on a mean IAT

[joecar]

01250003/COS3 should be present in your EFILive install... look under the LS1B Custom OS folder.

Full flash the 01250003 file into the PCM, then cal-only flash from your current 01250001 file, then fix any out-of-range cells... then read the PCM and save to file... make sure car runs the same as previous before making any edits.

[wesam]

will 01250003/COS3 work with all ls1 engines camaro,GTO,C5 ?
or is it specific for the GTO ?

[joecar]

According to the COS Upgrade Tutorial, the 0125000x OS's are based on either of 12202088 or 92111922.

What was your stock GM OS...?