Date: Wed, 6 Aug 2014 20:58:06 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Digifant II O2 sensor....My questions answered...
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The vehicle and motor..84 Vanagon with Inline VW...a 92 cabriolet 1.8 liter
head and everything else mounted on a 93 2.0 liter ABA block. I kept the
digifant engine management and used the 1.8 liter head because it fits into
the vanagon using VW diesel engine mounting system and no bumps or raised
rear deck..A lot of the parts are directly from a vanagon digifant system...
So my O2 sensor failed...perhaps because the wiring is/was aged and
brittle and maybe shorting out....I had another spare one. the same 4 wires
but not the VW plug. "We" deduced that the plug I had been running matched
the 92 Cabriolet wiring diagrams...so anyhow I wired in the other 4 wire O2
sensor and that worked fine for a few days, then IT failed also, or the
wires shorted out again, or perhaps the wires shorted out and caused the
second O2 sensor to fail also...I don't know for sure, but that seems
likely.
I looked for that particular O2 sensor with the proper plug, briefly,
but after seeing them priced way up there ($75+) and considering the state
of the wiring from my engine harness out to the existing plug...I decided
to simplify with a less expensive single wire Bosch.(<$30) I got one
from our Van Cafe California Vanagon supplier, who's tech told me it would
work just fine...and so it did/does. I had a question on whether to
attach the old ground wire from my computer to something...nobody really
seemed to know, for sure..so I capped it off, along with the two wires to
the heating element, which the single wire Bosch does without, also.
So I eliminated that sketchy plug and 3 rotten wires and simply spliced
to the signal wire, after cutting back that shielding a little to get to
wires in decent condition. The van ran just fine without any O2 sensor
connected, but very rich and my fuel mileage dropped to just 18mpg.. In
order to know if the O2 sensor I installed, rather than trying to test pin
outs or millivolts with a meter, I figured I'd just run a tank of fuel
through and see how far I got, thereby knowing if the sensor was working,
and if there was any decline in function using a single wire one rather
than the expensive heated one that cost about 4 times more. Happy to
report that I am back to my previous long time confirmed fuel consumption
with this tank giving me 25mpg driving some city but mostly rural..
I do not have a cat convertor in my system and the O2 sensor is right
near the exhaust manifold, so it heats up quickly, I guess, judging by no
decline in fuel economy...
Thanks to all who tried to help me with this...electronics in the engine
are not my forte... and I have to say any time I can eliminate 3 wires
and two plugs without any downside...I am all for that.
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