Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP 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).