Idle hunting and the T1 sensor 74 2.0 Options

[scottsilvertt]

My car is running good, stock FI.
After, New rings, and 1. getting injectors working(was brain) and 2. spark (too much corrosion on dizzy shaft, was sanding down the point adjustment, so I polished the shaft.) and 3. I forgot to attach rear ground strap, (so the ground was the parking brake cable) 4. New ignition switch.

Anyway its good now,
Except for that idle hunt.

Engine cold hard to hold idle.
Cold , If I unplug sensor T1 on top of intake box, it doesn’t hunt.

But when warm it becomes high idle.
If I unplug at warm, idle is prefect.

How do you fix this permanently?

Scott

[BeatNavy]

Scott,

Could be a couple of things going on here.

Idle hunt is often a symptom of lean idle mixture, and when you unplug the ambient air temp sensor (T1 sensor) on top of the intake it's enriching the mixture modestly, which seems to help. You should probably try turning the idle mixture adjustment screw on your ECU a click or two clockwise to see if that helps.

In terms of your warm idle, you need to adjust it the way it should normally be done: make sure timing is correct, warm up the car, and use a combination of throttle body bypass screw and ECU idle mixture knob. If the mixture is lean, changes to the bypass screw will have little effect. If rich, the effect will be large.