Need help tuning my supercharged 94 Z28!

[steveo]

eehack can test idle parameters in real-time. simply use eehack's 'control' section.

check idle 'override' and spark 'enable', then play with the idle speed and timing until it feels right. it will default to your existing target and timing.

you may want to do this in neutral too. and while warming up. experiment a bit at different temperatures.

you can get test a hotter idle by overriding both fans to 'off' while monitoring coolant temperature, so you don't have to wait until you are in traffic in the baking sun to figure out that your idle only works in your driveway.

if you check the 'steps' button, you can control the IAC motor directly (so the ecm isnt trying to hit an idle target), you can use this to experiment and see how it behaves in other cases.

there's a small clipboard button next to the idle and timing controls, if you click them, it'll copy those parameters to the 'notes' screen in eehack so you don't have to write them down. then use those settings as hints for new values to use in your bin.

edit: one more thing, the LT1 really likes its throttle plates nearly closed so it can use the idle passages. the passages are fed both by a bypass hole and the IAC valve. the passages run through the manifold and feed the rear and front of the plenum more uniformly than the throttle plates. every lt1 i've tuned tends to idle best if nearly all of the idle air comes through those passages. if you have to open your throttle plates to get good IAC counts, in my opinion it might be time to consider drilling out your throttle body's idle air bypass hole a bit.