2006 Silverado 5.3 A4 Start Up Flare Issue

[Mike Norris]

Hey All,

I have one I have not run into before and looking for a little insight or help. The truck is a cam and bolt on vehicle with a stock intake, TB and MAF.

The only issue is that on start up the idle runs up to the 2500-ish area and then comes down and is fine for the rest of the time. No idle hang while driving. Comes right to idle.

I have always adjusted the Base Running Airflow to get the idle parameters correct for driving and in gear and such. Usually I will get a little start up idle flare maybe to 1300 or so on everything I have done. This one is a bit odd for me and maybe related to it being a truck and needing something a bit different.

If I adjust down the Base Running Airflow it will let the idle dip or even stall. Fuel trims and timing all look good during this time. If I adjust the Base Running Airflow again no idle dip or stall, but a pretty high start up flare.

I have never had to change much of anything else with an idle on any car, but was looking through the different tables and the only thing I can see that maybe can have something to do with it is Startup Initial Airlow and the Frictional Airflow Initial.

Can someone explain these tables to me? I am thinking the Startup Initial Airflow is extra air at cranking and inital idle which if that is the case may be what I need to bring down some. Anyone with some info on this would be greatly appreciated.

I did not try to make any adjustments to the Startup Initial Airflow as of yet and do not have a log, but I did attach the current tune. It does seem that the trucks with a stock TB do need quite a bit more Base running Airflow then a car with the same cam and idle setup.

Thanks in advance for any info.

Mike Norris

[Mike Norris]

Just a TTT for a little info please.

Thanks.

Mike Norris

[kevmar]

try this out and see how it goes.

[slow67]

Try taking out more timing under the Startup Idle Flare Control vs RPM Error
It is under Engine > Spark Control > Spark Advance.

I would take away more timing with more RPM, as the table tapers off after +700 rpm.

[Mike Norris]

Thanks for the help guys, always appreciated for sure. Any other thoughts are welcome also.

When the customer gets back this way we will see what we can do.

Mike Norris

[wkdivr]

How did this turn out? Any better?