Annoying surge with AC on, i am at a loss...
Well my truck has an annoying surge when coming to a stop with the AC on... The RAF is dialed in +/- .5... I just can't seem to figure out what is going on... This all started when i added the 4L80 and CircleD converter... When the AC is off, i have no issues...
spec of the truck are:
2004, LQ9, Patriot Stage II 243s, 90mm TBSS intake, 220/224 .581/.581 115+5, Mild 4L80, CircleD 3C 3600, EFI Live, Efans, 4" intake, 100mm MAF, AEM Lts, Full 3.5 Magnaflow catback, 4.10s, TrueTrac
Did you do RAFPN idle tuning...?
Does the PCM see the P/N switch positions correctly...?
Yep, the issue is when i am slowing down to a stop, it starts around 15-20mph down to zero just with the AC on... If the AC is off i have no issues... Also i have not issues in P/N...
Ah, in gear, sorry I misread your post
yes sir, in gear, any thoughts?
I'm looking over some tables, I see that B4515 has an AC column, but I'm not sure that that is the cause...
You swapped from a 4L60E to a 4L80E...? And this only started happening after the 4L80E/TCC swap...?
That is correct... The last small diameter TC i had with the 60 was a nightmare to tune... It took awhile to dial in but i never had an issue with the AC surging...
Sometimes going from a stock converter to a lighter weight aftermarket converter can cause idle problem in gear because of the weight difference. Since it's AC related increase the values in the AC Torque Loss table. This will tell the PCM to add airflow when the AC is on. Start with a 25% increase and go up as needed. Make sure to crank the AC to max so the AC pressure increases where both fans kick on to test it under load. With a small cam like that, it shouldn't need much. The AC Airflow Ramp Out can be decreased to soften the dip once the AC is turned off.
My torque loss table is zero out in the stock tune, my torque loss IAT table has some values in it. I might copy over the torque loss table from an fbody.
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