Date: Wed, 27 Nov 1996 09:31:00 -0800
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: wabbott@mtest.teradyne.com (William Abbott)
Subject: Re: 87 Help AGAIN
I've got one experience with a bad catalytic converter and
it did NOT exhibit the on-again/off-again symptoms Tonya is describing.
It had melted and deformed (Late-model Rabbit, Owner hadn't thought the
O2 sensor really *needed* to be replaced...) and was blocking the exhaust
system. Idled so-so, made no power and ran terrible at increased rpm. It
*seemed* like a distributor problem... surprise, a new distributor didn't
help.
However, its also easy enough to check Tonya's- its the shorter
can just up-stream of the muffler, yes? 3 bolt-flanges on each end.
Spooge some liquid wrence on the bolts, wait overnight, use brute
force to remove three nuts on each end. Buy new gaskets and new bolts
for re-assembly. There's no reason to not run without the catalyst for
diagnostic purposes
In the one that failed, you could look down the pipe and it
looked all bloby and melted- like used chewing gum someone said at
the time. Use your household vaccuum cleaner to check whether large
quantities of air can flow through the converter. Check the muffler too
as along as you're at it, although, again, the on-again-off-again nature
of the problem suggests fuel/spark/timing problem rather than something
purely mechanical. YMMV of course. If the catalyst element broke free
and was rattling around in there, it might make for intermittant symptoms.
In California its illegal to sell a used catalytic converter, only
new ones are salable as parts. However, a 'donation' arangement was worked
out in this case and a previously owned converter was given at about
the same time as a 'donation' of $150 was made reciprocally.
Tonya, after checking the catalyst, I see you've taken care of
the obvious spark and fuel problems, and done things for the FI brain
like new sensors. If it smells like raw gas when having a problem, then
either its getting too much gas or not enough spark., but only once in
a while. I'm inclined to suspect your electrical system, particularly
since going into drive and coasting a short distance seems to 'fix'
the problem. I'd check, and replace if I didn't like:
1: Transmission grounding strap
2: Battery cables- check BOTH ends
3: Idle-stabalizer- try disconnecting it and running without?
4: Ignition wire from key-switch to coil
All should be clean, tight at both ends, etc.
In a better world you could check-out diagnostic parts like
library books, as long as you returned them in more-or-less as good
condition as you got them. They'd have catalytic converters, all kinds
of distributors, brain boxes, idle stabalizers, etc, etc. Oh well.
Nice dream.
Good luck! And keep us posted
Bill
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