madening rough idle

[Mac]

so i poked at the car for awhile tonight, didn't really accomplish much, but i came up with a couple ideas.

after i return the distributor to work i'm going to install a ford solid state 4 cyliner ignition coil module (for $15 why not)

try removing the idle cut solenoid and put a bolt in there in its place and see if that even works. rock auto sells the solenoid for $40, but at least using a bolt will show is its being a problem or not (hopefully).

[Petros]

One of these simply cuts off the fuel supply when you downshift or between shifts when the throttle is closed and there is high vacume in the intake manifold. the idea is you will not have unburned gas being sucked into the engine and out the exhaust when you use the engine to slow down (as in down shifting). I do not think these would cause idle issues, but it is possible, read the service manual on how they are actuated.

These should be easy to test, I would test them before I replaced them, and you likely could find a working one at a pull-a-part for a $1 or something.

Good luck

[Mac]

i asked a guy who comes into work and is a retired toyota mechanic, not that i think working at toyota makes you an expert, some people have that spark, and hes one of them.

anyways, i asked him about my craptacular idle and he said its caused by crud build-up around the vacuum orifice right below the primary butterfly.

he suggested two things,
1. cover the carb intake with my hand and rev it up a couple times, and the crud might get sucked into the intake.
2. remove the screw completeley and blow it clear with compressed air/carb clean.

i'll try both methods on Sunday, hopefully my tercel will finally idle the way i want it to. I asked him about the solenoids, and as i thought, they either work or they don't and if it idles (even poorly) its not the problem.

[splatterdog]

It will still idle without the idle solenoid working or even the whole idle circuit for that matter. My 84 idled poorly since I got it and I was fed up with overall performance and went weber(oh yes).

Anyway, I never did verify what went wrong in the end(no service manual at the time and unfamiliar with toyota) but the idle mixture screw could be bottomed out or removed with no change. Idle circuit was totally dead. If you have you had to really crank in the idle speed screw to maintian idle, the solenoid could still be at fault or a passage way is clogged.

Does turning your idle mixture screw make a difference? That might be the easiest way to determine if idle fuel is shut off.