Re: [AMC-List] Flashback - Bungs and boring.

[Matt Haas <mhaas@xxxxxxx>]

<snip>
> the O2 sensor is 'Original' ......with 174K miles on it -
> outdoors & up on a floor jack, we ran the engine after
> disconnecting the sensor pigtail - not much difference -
> the ECm hunted but overall that O2 sensor was shot -
> and frozen...
> 
> Terry builds custom Homes & holds a Masters in Geology -
> his idea of a relaxing weekend is in mountain caves, hauling bags
> of equipment on a rope  -
> 
> took him 15 min. to m'oose' out the O2 sensor - and the threads
> ..........were gone right down to the barrel.> Nightfall .
<snip>

O2 sensor sockets are worth every penny (I bought a Snap-On so it was 
lots of pennies but it's also the perfect size for thermal vacuum 
switches). My 96 Ram was but 8 when I replaced the factory sensors. I 
couldn't budge either one with box wrenches but both came right out with 
the right tool. Also, it helps to run the vehicle for a few minutes so 
the pipes are warm. Also make sure that you put anti-seize on the 
threads of the O2 sensor.

BTW, one wire sensors are usually good for about 50,000 miles and three 
and four wire senors are usually good for about 100,000 and should be 
replaced around those mileages. They usually get lazy when they fail and 
that doesn't usually trigger a "Check Engine" light (if they fail with a 
dead short or an open, that will trigger it). If you have a problem that 
makes the engine run really rich, you should also replace the O2 
sensor(s) after the problem is fixed. They will get clogged with soot 
and mess up the air/fuel ratio.

Also, on the surge issue, make sure the manifold and throttle body to 
manifold bolts are tight. My 68 American ran like you describe at one 
point but was only noticeable when hot. It turned out a few bolts 
decided they'd rather occupy the side of the road instead of the engine 
compartment. I replaced all the hardware, thread chased the head, and 
replaced the manifold gaskets. Problem solved.

Since it ran really rich, you may also have plugged passages in the 
throttle body and heavily carboned intake valves (rough running) and 
piston tops (pinging). GM Top Engine cleaner will do a great job with 
everything past the throttle body but you may want to drop the exhaust 
before the catalytic converter so it doesn't get plugged up with soot. 
The throttle body should be disassembled and cleaned but you should try 
and find the factory procedure for doing this. Some designs use plastic 
or rubber bushings and seals that will be damaged by soaking in 
carburetor cleaning. The factory procedures will warn you of these 
potential problem areas. Cleaning the throttle body is also something 
that needs to be done routinely on non-TBI fuel injection systems. This 
is usually something that needs done between 50,000 and 75,000 miles.

Here's a tip for o-rings (and other fun parts like grommets): Try 
soaking them in hot water for a few minutes before installing them (do 
not do this with A/C systems). They will usually soften up pretty well.

Matt
-- 
mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1967 Rambler American wagon
1968 Rambler American sedan
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