7730 tuning help with A1 file

[88GTTuesday]

Looking at the data log I do see that the IAC is trying to keep up with idle. down as idle increases and up as idle goes down. Im not seeing any parameter option to slow it down. most options have to do with A/C, TPS and start up temps.

as for adding timing and fuel, is that going to be done in the idle VE table. also what would be a bit? I wouldn't want to change to much and mess up something.

[steveo]

post the xdf you use, i'll help you figure out what parameters to fiddle with

[88GTTuesday]

A1_tpv5.xdf

that should be it. Hope that works

[steveo]

start by increasing your idle speed:

Commanded Idle Speed in Drive (F17)
Commanded Idle Speed in Park/Neutral (F19)

this is per temperature, so you can actually datalog what the temperature is when it starts running like crap and only change those cells. i would increase your idle RPM by 200 and see how that goes.

your ecm mask actually has the timing advance trick built in, it's in these tables.

Idle Spark Retard vs Idle Error (F1SPRTD)
Idle Spark Advance vs Idle Error (F1SPADV)

the way it works is, for example, if your idle speed is 50rpm low, it will add spark advance from the advance table's 50rpm column, trying to make up for that error. if it's high, it will reduce spark advance using the retard table.

one thing to understand when trying to stabilize a modulation (a surge) is trying to tune out the modulation completely often results in the control system itself creating a new modulation instead.

in my experience with an aluminum flywheel, increasing the values in the advance table and reducing the values in the retard table will help (it'll allow it to surge 'high' but fight harder to prevent it from surging 'low'). i would keep the values under 50rpm very low, though.

try that stuff first.

you have an IAC throttle follower going on too. if the stuff above doesn't quite do it, playing with this table should allow you to affect how quickly your IAC falls.

Throttle Follower Decay Rate vs MPH (F129)

[88GTTuesday]

Thank you for all the help. I really appreciate it. It will work on this this weekend. One question though, does it matter that I have a 5 speed? It's worded like it for automatics(drive,park,neutral). I forgot to mention before it's a manual, not sure if it matters.

[1project2many]

There should be a Flag for Manual Transmission. Often when this flag is set tables for park are used at all times.

[woody80z28]

I run a 3400 in Beretta on $A1 7730. The surging idle is hard to fix. The biggest improvement I found was actually replacing my Bosch o2 sensor with a Denso. Had a few friends that had the same problem and they all improved with a Denso o2.

Once I cammed it, I cut both the idle spark vs idle error tables in half and it helped.