Interference on FM after exhaust replacement on Honda Accord

Hi,

I recently had the mid-section on my 97 Accord exhaust replaced, and since
then I have been getting intermittent FM radio reception problems
(crackling, poor signal/tuning, general hiss or mono signal). This could
obviously be a coincidence, but I thought I'd ask first whether there is any
way an exhaust part could affect radio reception (I feel slightly silly
asking BTW).

I guess another possibility is a poor ground somewhere, or my aerial decided
to break the same day, although it affects music delivered by my inline FM
modulator as well? I thought maybe the stereo is on its way out, but the CD
changer plays perfectly. I'm having trouble thinking how to troubleshoot
this one!

Thanks in advance for any suggestions,
Al

 

Exhaust systems can act as an aerial and radiate interference. To prevent
this some have earthing straps. But it's a long shot. I'd say it's
unlikely any of the car aerial etc wiring goes anywhere near the exhaust
so shouldn't have been damaged or disturbed when fitting a new one, so
it's likely just coincidence.

If it uses an aerial built into the rear screen etc there will be a RF amp
associated with this and the likely cause of the problem - poor connection
or simple failure.

 

We were somewhere around Barstow, on the edge of the desert, when the

In addition to what Dave suggests, I'd also have a look at any
suppression caps or earth straps that might be fitted under the bonnet
or under the floor - they might have been dislodged by the Kwack Fart
fitters.

 

most japanese and many english cars have an exhaust earth strap, if it isn't
there, add one. any non earthed part can give interference, including
wheels! some vehicles have a brush in the hub bearing cap to avoid this.

 

Al's exhaust grounds through a bolted flange just behind the oil pan.

However, Al may want to check for the existence and integrity of the engine
ground strap. This item will attach to a valve cover nut and go to either
the rad support or a shock tower. It's common for these to break or get
left off entirely.

 

At DC yes it is grounded via the engine, but at 100MHz the impedance along
the exhaust is high and all sorts of radio noise (clicking crackling) could
build up along it. On some cars the manufacturer may have found they needed
to add a ground strap at some point along the exhaust to stop interference.

Mark

 

"Al Reynolds" wrote

If the previous suggestions don't work, check to see whether the mid-section
is properly connected to the other sections. The metals may be rubbing
against each other, creating sparking.. maybe. Always possible....

 

Honda does not do this, to my knowledge. I've never seen such a thing on a
Honda exhaust.