kirk@bunker.UUCP (David Kirkpatrick) (09/19/83)
A few months ago I installed a JVC cassette/radio unit in my '74 260Z. Everything went OK and I was very pleased with the sound, I did have a problem listening to some of the weaker FM stations if there was any metal around (parked close to lamp standards, overhead power lines or other cars) but the closer FM stations came in loud and clear. Then last week I put my car in for a service which included replacing the spark plugs, distributor head and rotor arm. The trouble is that the radio now suffers from interference all across the FM band, it varies from a soft clicking sound when the engine is idling, to a high pitched squeal at about 3000 revs. The interference stops completely when the engine is switched off. I returned to the garage where the tune up was done but the mechanic said that he had only used factory authorised parts and as the radio was non standard he wasnt responsible for any effects his work had done. Can anyone suggest what is wrong with the new set up and how it can be fixed? .....decvax!ittvax!bunker!kirk David Kirkpatrick
rs55611@ihuxk.UUCP (09/20/83)
To keep ignition noise down, most modern cars use resistor-type spark plug wires. Alternatively, resistor plugs can be used. Without one or the other, ignition noise will be heard. You should check out the spark plug type you used top have, as well as the new plugs, to see if they were/are resistor plugs. If the old ones were but the new ones aren't, that probably implies that the wires aren't resistor wires (I assume the wires weren't changed?), and that you now have to change either wires or plugs to resistor type. The usual approach is to have resistor wires, not plugs. Bob Schleicher ihuxk!rs55611 Bell Labs, Naperville, Ill.
stekas@houxy.UUCP (09/20/83)
After much painful experience I have become somewhat of
an expert at car radio noise. Ignition noise pickup is
a common problem which may not always be cured by resistor
wire or plugs. Before spending money and gearing up for
some hard work, check the following:
1) The connection between the antenna base and chassis. A
bad ground here is a common problem. After disconnecting
the antenna from the radio, see that the braid gives a dead
short to ground.
2) While you have the antenna disconnected, see if you can
still hear noise through the radio. If so it's coming in via
the +12 supply and that's the JVC's fault.
3) Also disconnect the alternator to make sure its not the cause
of the noise. I recall when my noise problem magically vanished
one night, when the headlights dimmed and the engine started
missing I realized why!
I hope these types are timely for a few frustrated netters.
Jimjsf007@trsvax.UUCP (09/29/83)
#R:bunker:-28000:trsvax:55200015:000:166 trsvax!jsf007 Sep 21 08:50:00 1983 The mechanic probably did not use resistor plugs and shielded spark plug cables. That's what it will take to fix the problem. Steve Fintel ...trsvax!jsf007