Idle adjustment screw for D jet, How many turns before idle should change? Options

[jsaum]

I was helping Matteyp tune his car last night and it's the first time I have worked on a fuel injected engine. We got the dwell set and the engine timed with the light, it's running better but when I tried to adjust the idle speed the adjustment screw didn't seem to affect the idle speed I gave it two full turns in each directions. My questions is how sensitive should this adjustment be?

Jsaum

[Prospectfarms]

It's very sensitive.

what did you set the dwell to?
How did you set the timing?

How is the the action on the advance plates inside the distributor and does the vacuum advance canister hold a vacuum?
Do the plates move freely or get stuck in any position?

Rich

I had no idea what the screw did to affect idle until I came across a diagram. If I understand it correctly, the screw changes the effective size the throttle chamber -- it looks like an adjustable carburetor throat. So, if turning the screw doesn't do anything either the motor's not in tune or there air leaking in somewhere.

I was told and recently learned first hand, that making sure the valves, time and dwell are in spec makes troubleshooting the rest of the fuel system so much easier.