Date: Mon, 10 Sep 2007 17:35:25 -0700
Reply-To: Michael Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Michael Elliott <camping.elliott@GMAIL.COM>
Subject: Re: My poor MPG, O2 sensor seems okay
In-Reply-To: <00e601c7f408$80461220$0201a8c0@kaos>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Kenneth, I got one of your O2 sensor monitors a couple weeks ago and
did a quickie clip-lead hookup to the sensor this afternoon in addition to
looking at the voltage with my DVM. The monitor works as advertised, a
good deal for a measly 20 bucks, and the little bouncing dot is fun to
watch. On Mellow Yellow it mainly ranges one or two bars above and below
the center bar, maybe spending a little more time on the center bar, which
I presume to mean that on the average the mixture is neither too rich nor
too lean.
I can confirm that Mellow Yellow exhibits the same behavior as your web
page describes, viz:
1> When the engine is first started the Dot * "floats" in the middle of
it's range. (DVM says about .35mV at first)
2> As the engine/O2 sensor starts to warm the Dot creeps towards rich.
(Yup -- slowly climbs to about .45mV).
3> When the ECU switches to closed loop operation the Dot swings back and
forth rapidly. (Yup, centered around .55mV. Mark Drillock suggested
hooking my scope to the sensor to see how exciting it truly is. I'm not
sure I'm ready for that much excitement!)
I have not tested full throttle to see if my sensor reacts like your next
step: "4> At full throttle the Dot stays pegged in the rich zone," which I
will do tomorrow.
With regard to your Step 5 "An old O2 sensor caused the Dot to jitter and
move lazily as opposed to a new sensor which gave crisp and rapid Dot
movement from one end to the other." I can say that the dot here bounces
around in quite a lively fashion with no laziness observed.
Mark suggested that I take the van out onto the highway and see what the
monitor reports. This is a good idea since highway driving is about 95% of
my driving this should give me an indication of whether my poor gas
mileage is because it's all going out the tail pipe.
The "Here is a good link O2 LINK" link on your page is broken, BTW.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
On 9/10/2007 5:12 PM Kenneth Lewis wrote:
> Mike,
> If you read the tech sheets there is more to a "good " O2 sensor than
> voltage swing. They talk about "slow" sensors also. I have some info (plus
> my O2 sensor monitor) on my website : http://neksiwel.20m.com/
> Ken Lewis
> /
>
>
> ----- Original Message -----
> From: "Mike "Rocket J Squirrel" Elliott" <camping.elliott@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Monday, September 10, 2007 6:47 PM
> Subject: [VANAGON] My poor MPG, O2 sensor seems okay
>
>
>> As I've posted previously, my 84 1.9L auto only gets about 15.5 MPG
>> while others have reported somewhat higher mileage. Even after filtering
>> out those who seem to be quite optimistic, and paying especial attention
>> to those who deny not keeping careful records, Mellow Yellow still
>> trails the pack. It gives us great sadness.
>>
>> It has been proposed that my poor numbers might be due to a funky O2
>> sensor, or crummy compression. I'll get to the compression tomorrow or
>> the next day, but right now I have hooked up my handy-dandy voltmeter to
>> the sensor and with the engine warmed up, it is outputting between .36
>> volt and .66 volt, ranging around about .55 volt. This seems kinda
>> normal, from what I read.
>>
>> --
>>
>> Mike "Rocket J Squirrel" Elliott
>> 71 Type 2: the Wonderbus
>> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
>> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>> KG6RCR
>>
>
>