tomulrich

iTrader: (2)

1998 C5 Corvette
Mods:
427 ci
Cam is a Futral custom hydraulic grind dur @.050=252/260 lift is .680 on intake and .660 on exhaust. Ground on a 113 center.
11:1 compression
fully worked heads with VERY good flow numbers at all lifts
90mm tpis TB
Fast intake.
Halltech system with filter in front license area.


Tuning MAFless...dont even have a MAF

Car starts right up..idles for a few seconds and then starts to surge...to the point that it stalls.

I have searched the forum..and tried all the tricks.......my idle is set at 950.....I have tried adding timing....my wideband is running at 13.00


I have a 5/32 hole in the throttle blade.....should I make it bigger?...I dont have an actual IAC....because the TB is drive by wire.....so I am not real sure how I should be tuning with this type of throttle body.

Please help....me with this. Please do not refer me to other links....I have read them all.

Also can someone go into detail on how to use the histogram with wideband and VE tuning..

Also When going MAFless .....I know you tune with the secondary VE table........but do you tune on the "high octane or low octane" table.....when tuning MAFless...



THANKS for all the help...Tom

Cal

iTrader: (1)

Since your TB is "fly by wire" I believe you do not have to drill the throttle plate, but I could be wrong. If that were an fbody TB, I know you would need a bigger hole than that with a cam that size.

Nickn20

IMO you car should be a tad leaner at idle, shoot for 14.0 in open loop, ideal is (stoich)14.7 but with weather coditions that can change I like 14.0 better. also are you doing idle relearns? I am not sure if they are even neccessary without the maf...... oh and Idle speed I would bump that up a little, try 1000-1100 or so, its s fairly big cam, I know it sounds sweet at lower rpms, but this may help. are you running 02 sensors? if so they may messing up fueling also, when the car switches in to closed loop, and then it dies.

Good Luck.