Running Lean, only after startup

[Kevin Doe]

I have noticed over the years that when I start my car, it runs very lean compared to commanded for a short while. Then it seems to fall into a BEN of ~0.98-1.00. I command 14.65 AFR in my idle cells. I have tuned the start such that I get a perfect start with minimal rpm flare. It starts very quickly, hot or cold w/o touching the gas pedal.

Now, for some reason it starts and runs in the 16-17 AFR range for like 2-3 minutes after I start it, if I just let it idle to warm up. Once its warm up, my AFRs are perfect. It doesn't have to do with the IAT, as I'm on COS3 and I've tuned the A0014 table pretty extensively and it seems to do a pretty good job.

Does this point to a deficiency in the IAT/ECT temperature blending for my engine? I do not have the coolant lines routed through my throttle body like normal, and my intake system differs significantly from stock (its a dual ramhorn looking 3.5" intake system going to two seperate cone filters behind big openings in the bumper cover.

Anyone care to point me into the right direction?

[mr.prick]

If your OS has {B3605}, richen up the lean areas.

[Kevin Doe]

I do not have B3605.

I guess I should have specified, I'm running a 2004, 1MB LS1 computer.

[mr.prick]

Which OS?
I just looked at a stock '04 ZO6 file and {B3605] is there.

[Kevin Doe]

04110003

[mr.prick]

How about {B3642}

[Kevin Doe]

Wouldn't that just make the command richer. Sure it would also make the acutal AFR richer, but I don't think that would address the problem.

Why is the acutal so far fom the command during warmup?

What things can effect the actual AFR, but not the commanded AFR.
Volumetric efficiency table is all I am aware of, and mabye the temp blending tables? Clearly I don't want to modify the VE table to fix thsi issue, then I'd just be off at operating temps.

[427]

Did you try the {B3642} ?

[jfpilla]

Are you running the AIR pump? If so you can turn it off or shorten the on time.

[Kevin Doe]

No air pump. No emissions stuff at all really.

[samh_08]

x2 on this problem. Subscribing ;)

[driver456]

Any answer's to this,Having the same problem on hot start up.

[foakley]

Bit of a thread dig, but you didn't end up finding the problem at all? I got the same thing... VE dialed in for idle, idles great when warm, cold start & after start start at 15+ lean and works it's way to 19 unless I throttle it to keep it safe and then it becomes happy... :/ very weird...

[joecar]

Post your tune file and some logs.