GenIII HCI - HP tuners help needed - rolling stop stall

[savela]

Hello Gents -

THE ENGINE -
I've got a gen III 5.7liter 2002 Formula 5.7/T56/ECU transplant into a 99 E36 M3 with H/C/I/Headers.
TFS GenX515 HC Pkg: sloppy stg 2 cam, TFS 215 Heads.
Camshaft specs are 228/230 duration, .585 in./.585 in. lift, 112 lobe separation angle
Cylinder Head, GenX? 215, CNC Competition Ported, Assembled, 64cc CNC Chambers, Ti Retainers, GM LS1, Each
Texas Speed 1.72 RR's
1-3/4" LT Headers
GTP 36# Injectors

GEN III ECU - tuned with Hp tuners.

C5 Corvette Airbridge with AF in front air dam.
Dual 3" Exhaust: LT's, 3" Cat's, 3" X pipe, 3" Super turbo Muffs.

DYNO -
Car put down 417rwhp and 380rwtq.

PROBLEM -
Car runs great with good AFR, and no Knock every where, starts great hot or cold, does not stall hot or cold......

HOWEVER - my 1 problem that I have been unable to correct -
I've got a slow speed rolling to a stop stall issue when HOT only.
Also note If rolling at speed 20mph UP..... then let off gas idle drops down to desired rpm no problem and no stalling.
It's only at parking lot speed or in traffic when hot...... I drive in 1st gear up to 2-5mph..... then let off gas hit clutch and roll w/traffic.... idle goes unstable and drops to 400rpm.... desired is 900..... sometimes it will recover..... barely or it will stall if I don't stab the gas pedal quickly. Very hoopty way to drive

Intake - is a mamo ported Fast 92 with mamo ported big mouth TB, un-drilled plate.

IAC counts runs at 18-30 at idle. It does not change when this rolling to stop stall condition happens.

Idle timing @ 22 Deg which seems to give good vac at idle. I tried 25 and ex got smelly and idle unstable.

TPS shows 0 at idle. I have not tried to crack open the TB with the allen bolt, then reset TB blade yet.

Let me know where to work in my tune for this if you can help.

I can share my tune file and log file if it will help.

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UPDATE - just did a quick drive and attached the log file.

Now I'm noticing after 198 Deg F coolant.... car will try to stall on decel at all speeds...... I have to blip the throttle.
I also noticed the IAC counts drop to 12 during this condition.

thx for any input.

[savela]

going to visit my tuner next Fri... will post up what he comes up with. thx.
4

[Ben Charles]

Needs more air

[savela]

Thx Ben!

I'll see my tuner next week.

I was trying to learn myself.....

my idle LTIT -8 lb/hr
STIT -16 lb/hr

my idle desired air flow shows 34.5 lb/hr
my set base idle air flow (programmed target) is 55 lb/hr

so per above I was interpretting:
1 -per LTIT - i was way rich.
2 - per idle desired air flow my target air flow is too high!

confusing.....

[Ben Charles]

This isn’t confusing at all, idle desired lies sometimes and that’s too rich period for a cam setup!! Hopefully your tuner can figure it out, if not give me a shout, I can

[savela]

Ok thx Ben for the support.

I'm working with MTI in Houston, Tx. They have been in the ls game for 20 yrs.

[Ben Charles]

Ok thx Ben for the support.

I'm working with MTI in Houston, Tx. They have been in the ls game for 20 yrs.

Good luck with that, they should have got it right the first time

[savela]

In their defense..... I have made the following changes since their last tune:

AIR INTAKE -
OLD - 90 deg el at TB - 4" plastic pipe - Cone filter behind head-light.
NEW - C5 corvette airbridge over rad - filter in lower front bumper grill.

ENGINE -
OLD - 1.7rr's HS
NEW - 1.72 Tex Speed RR's

EXHAUST -
OLD - dual 3" cats - dual 2.5" borla x resonator - dual 2.5" borla muffs
NEW - dual 3" cats - 3" X - dual 3" super turbo muffs


====

Question -

I'm going to change my dual 3" super turbo catback out for dual C6 mufflers, and install cut-outs for free flow.

Should I wait and have my tune updated after I make this ex change.... OR can I just update the tune with the dual 3" super turbo's...... and all will be good for the c6 muffs and cut-outs option?