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Posting-Version: version B 2.10.2 9/18/84; site watmum.UUCP
Path: utzoo!watmath!watnot!watmum!gvcormack
From: gvcormack@watmum.UUCP (Gordon V. Cormack)
Newsgroups: net.auto.tech
Subject: Re: ignition noise
Message-ID: <309@watmum.UUCP>
Date: Tue, 29-Oct-85 22:01:32 EST
Article-I.D.: watmum.309
Posted: Tue Oct 29 22:01:32 1985
Date-Received: Wed, 30-Oct-85 05:45:03 EST
References: <988@panda.UUCP> <1185@cbdkc1.UUCP>, <10826@ucbvax.BERKELEY.EDU> <883@homxb.UUCP>
Organization: U of Waterloo, Ontario
Lines: 31

> 
> I have an ignition noise problem that is clearly RF related,
> i.e. is not audible during tape operation.  The problem
> started after I had the car tuned up.  I have all
> the usual: resistor plugs, wires, distributor condenser etc.
> What could have been done during the tune up to cause this
> interference to start?
> 
> Herman Silbiger ihnp4!homxb!hrs

1.  Are you sure they put in resistor plugs?
2.  A spark plug wire could have been broken.  Check the continuity.
3.  There is a noise suppression capacitor between the positive
    coil connection and ground.  This could have been disconnected
    when the tune up was done.  (this may not exist with electronic
    ignition.)
4.  One or more of the spark wires may be disconnected either at the
    distributor or spark-plug end.
5.  A spark plug may be broken internally (unlikely).
6.  The rotor or distributor may have eroded or the insulation on
    the wires become weak.  These are not caused by the tune up, but
    the stronger spark after the tune up may cause these weaknesses to
    make more noise than before.

To help narrow down the source of the problem, try to estimate the
frequency of the ticks.  At idle, if the ticks are approximately the
same speed as a clock, look for a problem with one plug or the wire
leading to one plug.  If the ticks are much faster (almost a buzz),
look for a problem in the common part of the circuit (coil, coil wire,
distributor) or else a problem that is uniform for all cylinders
(e.g. non-resistor plugs).