G3 Accord intermittent rough or low idle

Maybe I should say intermittent normal idle. When my '88 Accord DX
(carbureted, automatic) warms up, the idle is often rough at a stop in gear
and at idle. It is bad enough that the hood shakes and the steering wheel
wiggles. If the idle isn't too low, it usually still vibrates enough to
make the steering wheel wiggle rather obviously.

In an attempt to fix this issue, I replaced the idle boost diaphragm that
boosts the idle for the A/C and for the auto in gear. I changed the
transmission fluid very recently and that had no effect. With the gas
pedal, I can mostly get rid of the shake by raising the RPM to what appears
to be a little over 800 RPM on the built-in tach. Even so, if it has a bad
case of the shakes, you can still see and feel significant vibration in the
steering wheel at this RPM but it is tolerable. Sometimes, on the same day
it will be pretty smooth. Any ideas?

Aron

 

Try adjusting the timing. I believe your vehicle has a carbuator. If so,
you might try adjusting the carbuator. I seem to recall that there is one
main screw that you can turn left or right that helps to adjust the idle.
If you know the location of that screw, adjust it while the engine is
running. Also--check all of the vacuum hoses to make sure they are
connected and don't have any holes. Also, adjust the points.

 

It is carbureted but it has no points. It has some kind of igniter system
that uses vanes and an inductive pickup, or something to that respect. I
have checked the vacuum hoses and the timing in past months trying to get to
the bottom of this problem and have not found the answer. As far as
adjusting the idle, there are a few screws for that along with one for the
mixture. Sometimes it is idling rough when the RPM is appropriate according
to the tach. That's what makes me hesitate to adjust the idle to fix the
problem - it seems like the problem will still happen.

The second thing that makes me hesitate to adjust the idle is that the
procedure is "idle speed/mixture adjustment". I don't know if it's OK to do
one without the other because the steps have you do both. I don't want to
mess up the mixture. Also, to adjust the mixture, you have to unbolt the
carburetor to get the cover off the mixture screw. This will mean replacing
the gasket and maybe a number of old vacuum hoses. I don't want to deal
with all that unless I am sure it's going to fix the problem.

I'm happy to hear any suggestions from anybody though.