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Path: utzoo!andy
From: andy@utzoo.UUCP (Andy Rubaszek)
Newsgroups: net.auto
Subject: 1981 Buick Detonation Problem 
Message-ID: <5951@utzoo.UUCP>
Date: Thu, 12-Sep-85 15:10:07 EDT
Article-I.D.: utzoo.5951
Posted: Thu Sep 12 15:10:07 1985
Date-Received: Thu, 12-Sep-85 15:10:07 EDT
Organization: U of Toronto Zoology
Lines: 28


I hope someone can suggest a solution to this one. The car is a 1981 Buick
Electra station wagon with 50K miles on it.  The problem is that it pings
under partial load at cruising speed when the engine is hot.  It behaves
when cold and under full load (i.e. it downshifts and accelerates smoothly
with no ping when you tromp the gas pedal even when fully loaded AND going
uphill).  There is also a barely-perceptible hesitation and then a more
pronounced lack of guts under partial acceleration at cruising speed, but
plenty of power under full throttle. The engine is 5.0 litre.

There is no obvious sign of overheating; fan and belts are ok, thermostat
is not stuck. The carb has been overhauled (one mechanic claimed the mixture
was too lean and that was causing the ping). EGR valve is fine; I replaced
the gasket just in case. Timing is already retarded 4 degrees; loss of power
becomes too noticeable retarding more. Vacuum hose routing was checked.
In short, I don't know where else to look. The only solution I can come
up with is trying cooler spark plugs, but since the car is used a fair bit
in city traffic, I am concerned about fouling and carbon build-up with a
cold plug. (Oh yeah, the upper cylinder area was "de-carbonized" with the
gunk you pour into the carb.)

So... if anyone has had a similar problem or can offer any suggestion, I
would really like to hear from you.  Thanks in advance.

				Andy Rubaszek @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!andy