Date:         Sat, 10 Mar 2001 21:48:57 -0500
Reply-To:     Schmidt <schmidt5@HSONLINE.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Schmidt <schmidt5@HSONLINE.NET>
Subject:      interesting for o2 sens/power loss topic
Content-Type: multipart/alternative;

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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