Hi Jay,

A person can see what volt signal the 02 sensor is sending to the ECU by
using a digital multi-meter, in open loop or closed loop. Might be good info
for your testing.

Happy Traveling,
Mark Ingalls

>From: Schmidt <schmidt5@HSONLINE.NET>
>Reply-To: Schmidt <schmidt5@HSONLINE.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: interesting for o2 sens/power loss topic
>Date: Sat, 10 Mar 2001 21:48:57 -0500
>
>History: 84 westy loses power while driving-top speed 60 if lucky, idled
>rough, poor mpg(-all intermitently and symptoms would temporarily resolve
>by turning off key).  Numerous new parts, AFM cleaning, etc.  Exhaust is
>all new last year with no cat.
>
>Hypothesis: This condition will not rear it's ugly head if I disconnect the
>o2 sensor.  My power will stay within normal limits and my mpg will greatly
>improve. Why? I don't know but the van seemed to run better when it was
>dc'd, so I ordered a new one.  Once the correct new o2 sensor was properly
>installed, the syndrome returned.
>
>Test: (140 mile round-trip to work) The test this week consisted of driving
>to work once with the sensor connected, then refueling and driving the same
>road with the o2 sensor dc'd.
>
>Data:  trip #1 with o2 sensor connected: 140 miles /9.683 gal= 14.46 mpg
>trip #2 with o2 sensor dc'd: 140 miles/ 10.316 gal=13.57 mpg
>
>One may assume that the van performed better with the o2 sensor properly
>connected.  Read on!!!
>
>With the NEW o2 sensor connected, the van would lose power every 10-20
>miles to the point where it would pass nobody, it refused to go faster than
>60 mph on level highway, 45-50 on a mild incline and this is with the
>accelerater floored.  I stopped three times to temporarily breathe some
>power back into the beast(by shutting her off), but my average speed
>overall was about 60 mph.  Idle at stop was crap- one foot on the brake,
>one on the gas.
>
>With the sensor dc'd,  I NEVER ONCE LOST POWER IN 3 TRIPS OF 140 MILES
>EACH.   Further, it idled nice and smooth at a stop,  and my average speed
>was about 72 mph!
>
>This van has NEVER gone the 140 miles without the power loss occurring.
>Now that the o2 sensor is dc'd, she made it three consecutive trips
>flawlessly!  Coincidence?  Not a chance!
>
>Conclusion: Disconnecting the o2 sensor cured 2 of 3 problems; namely the
>power loss and the rough idle.  It did NOT drastically improve mpg as
>expected.
>
>Notes: D/C ing the o2 sensor made a HUGE improvement in the driveability of
>the vanagon.  I liken it to the difference in driving an old splitty verses
>a modern machine.  The 02 sensor gives the van that vintage feel of no
>power and the constant hope for a downhill grade or a slow semi-truck to
>draft.  It's kinda embarrassing and I think people snicker at the slow van.
>I made every attempt to minimize variables and limit it only to dc ing the
>o2 sensor ie same fuel, same road, same everything.
>The decrease in mpg with the sensor disconnected is misleading since I was
>able to go 72 mph(13.57 mpg) verses 60 mph(14.46 mpg).  At less then 1 mpg
>difference, I think the fuel economy is actually better with the sensor
>dc'd, but I can test that later.
>I was truly hoping the fuel economy would improve by dc ing the o2 sensor.
>I'd like to know what is "average" for a 84 westy.  Average-as in across
>the board if you toss out the 10 % that are excessively high and the 10%
>that are excessively low.
>End result in mpg testing is that when my family goes to Florida next week,
>we have to take the 97 Suburban now because the mpg is better...(wife
>giving her victory snicker in background).
>
>Question: If the o2 sensor gives the ecu feedback and (yadda yadda) gives
>you the best mpg, AND I am comfortable with the very minimal mpg loss with
>it dc'd, can I run without it forever without hurting anything since it
>drastically improves the driveability as above???
>
>I can't wait to hear the thoughts of the list.
>Jay in Seymour Indiana

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