Jim Grant's Tech Tips
'89 Accord LX, Rough Running/Misfire
Q:
I've
had my '89 Honda Accord LX for six months now and I've spent a great deal
on trying to locate a problem with a constant misfire. I've changed all
ignition parts including the cap, rotor, wires, plugs, coil, and igniter.
I've also cleaned the carburetor and changed the air filter and PCV valve,
adjusted the valves and timing belt. The problem is that I can not properly
time it since the mark on the flywheel seems to jump around. It won't
stay still like it should. I've got it set to a margin on the mark settings
but there is obviously something wrong. I'm looking towards an intake
vacuum leak or a distributor fault. What are some ways to detect a fault
without special tools? I'm sick of spending money on needless parts. It's
getting to be a headache. This miss is also noticeable throughout the
driving range.
-
Ben
A:
If
the ignition timing is jumping around so badly that you have to assume
average you may have just found the problem. I would suggest a close inspection
of the distributor. Remove the distributor cap and grab the rotor and
see what type of movement can be found. There will be rotational movement
due to the mechanical advance, but there should be very little side to
side play. If nothing seems out of place then remove the distributor and
inspect the distributor drive and the bearing in the lower part of the
distributor housing. Make sure the pin that locks the coupler and the
coupler (the part that engages the cam) is not worn or loose. I have to
trust when you say the timing belt is installed correctly that the tension
is right. If there is a loose or worn distributor component it can create
a variety of driveability problems. Stabilize the ignition timing and
you'll likely have a better running engine.
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