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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!inuxc!pur-ee!uiucdcs!convex!tmorris
From: tmorris@convex.UUCP
Newsgroups: net.auto
Subject: Re: 1981 Buick Detonation Problem
Message-ID: <82600011@convex>
Date: Wed, 18-Sep-85 17:57:00 EDT
Article-I.D.: convex.82600011
Posted: Wed Sep 18 17:57:00 1985
Date-Received: Fri, 20-Sep-85 06:41:49 EDT
References: <5951@utzoo.UUCP>
Lines: 42
Nf-ID: #R:utzoo.UUCP:-595100:convex:82600011:000:1963
Nf-From: convex.UUCP!tmorris    Sep 18 16:57:00 1985


	There are a couple questions that you could answer that would
help diagnosis of your problem:
	1. Did it work fine before , or did you acquire it with this 
           problem ?
	2. Did it occur after a tune-up ?
        3. Did it occur with the onslaught of hot weather ?


       I used to be a tech for a GM dealership and had to deal with
a quite a few "problem pingers". Here are a few off-the-wall things 
that I have located that fixed the ping:
        1. The thermostatically controlled air breather valve did not 
           switch from hot to cold incoming air source.
        2. The fan clutch was shot and caused overall higher temps.
        3. The cooling system had a circulation problem.
        4. The valves had been ground too close and had sharp edges.
        5. The valves had deposits that could only be removed by
           removing the heads and cleaning with a power wire brush.
           (usually the result of a steady diet of cheap gas or 
            leaking valve guide seals).
        6. The a/c condenser was full of bugs , causing higher temps.
        7. A defective water pump had a casting defect which cut down
           the circulation to the right 4 cylinders.
        8. The cruise control had a vacuum leak in the diaphram.

	You had checked all the usuals , so I left them out. Generally
what you want to find are:
	1. Things that make the engine (or a certain combustion area)
           get too hot. Use a gauge to find out.
        2. Things that make the mixture too lean AT THE TIME THAT IT PINGS.
        3. Things in the combustion chamber that retain or focus heat.
        4. Things that prevent the EGR from coming on THE PROPER AMOUNT at
           THE PROPER TIME.
         
           There are probably others , but I can't remember them now...
                              
                               HAPPY MOTORING !
                                


                                         


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