1991 Chevy C1500 full-size pickup 5.7 liter V8 engine with TBI (Throttle-body injection), 4-speed automatic 2-wheel drive, with 3.42:1 rear gearing. Used as work truck to haul parts.
!clutch fan. Electric fan added. PCV filter. Underdrive crank pulley. Air-dam added. 180*F thermostat. Plug-wire separators. Sparkplug clipped ground-straps 1/2 way over tips. 5w-30 oil. Tires at 38 psi. Ported TBI unit. Left and right intake manifold plenums fully divided/separated. Innovate Wide-band O2 sensor.
*Minimum Air Rate (throttle blade opening for idle) increased significantly and IAC (Intake Air Control) steps reduced down to 10-steps for warm operation. This results in less air bypassing the throttle blades and better fuel atomization and distribution at idle.
*Full ECM tune via flash-chip. Tuned to run Open-Loop full time. Many calibrations changed. VE table re-calibrated. IAC, TCC, and DFCO routines modified.
Leaned out cranking & time-out (warm-up) fuel tables, and normal operation tuned to 15.8:1 AFR.