90 Accord ignition noise in AM radio

Where is the ignition noise suppressor in this Honda. In some other
cars there was a capacitor across the distributor but with the
"pointless" distributors I think that is no longer true. I use the
standard spark plugs and have not changed the high tension wires. The
noise is worse on low AM frequencies and varies with engine speed.

 

How old are the plug wires?

Do you have aftermarket wires/rotor?

 

In nearly every case I've seen, ignition interference on AM frequencies is
the result of a poor ground at the antenna. Repair requires unmounting the
antenna (which is easy if the antenna is in the rear fender, otherwise could
be difficult) and scraping the metal under the metallic parts of the
antenna. Scotchbrite or fine emery cloth are good for that.

The "condensor" (capacitor) in the old Kettering ignition was to allow the
points to open without bleeding off the energy in an arc across the points.
There could be a bypass condensor on the 12V side of the coil, though.

Mike

 

My honda with 115,000 mi has the original plug wires and rotor.

Thanks Bob

 

I do believe this model does in fact have a radio-suppression capacitor in
the feed wire from the ignition switch to the coil. Civic-based cars of the
same era have a cap that looks a lot like a Kettering condenser.

 

I am going to try grounding the antenna first (it's free). II tried
several of the online parts places ie, Majestic and found no capacitor.
I can always try my dealer only 2 miles away.