Date: Tue, 11 Sep 2007 15:28:03 +0000
Reply-To: rubatoguy@COMCAST.NET
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Todd Last <rubatoguy@COMCAST.NET>
Subject: Re: My poor MPG, O2 sensor seems okay
This is very true, I have had this happen multiple times.
I think it can also happen from a buildup of brake pad dust. I have had some success with washing the wheels and calipers really well with a strong stream of water to clear-up sticking. This can also happen if you do a brake job and neglect to use caliper grease.
Also a good idea to regularly change your brake fluid.
Todd
'88 Westy
-------------- Original message ----------------------
From: "Jack R." <jack007@COMCAST.NET>
> Mike,
>
> I always bring a non-contact thermometer to check the wheel temps, sometimes
> a brake caliper will seize up, and if you see a higher temp at one of the
> wheels, that's your clue. MPG goes down if a brake is always rubbing!
>
> Worth a try.
>
> Jack R.
> 84 Westy Wolfie, tranny going back in Today for the Bus Boo!
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Michael Elliott
> Sent: Tuesday, September 11, 2007 1:30 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: My poor MPG, O2 sensor seems okay
>
> Hm. Well, I haven't noticed any loss of power. I have a "reference" drive:
> a climb from sea level up to about 7,000 feet which we take a couple times
> a year to a favorite campground. The van seems to pull up the grades at
> about the same rate as it has from the beginning.
>
> --
> 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 8:43 PM pdooley wrote:
>
> > The value is having something to reference.
> > However it looks like you are already past this point in your diagnostics.
> > I thought you needed to know since you indicated the scope results
> wouldn't
> > mean anything.
> >
> > If your compression is low enough to kill your fuel mileage you would
> > probably experience a noticeable loss if power, but maybe not if the
> > progression was gradual.
> >
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> > Michael Elliott
> > Sent: Monday, September 10, 2007 10:51 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: My poor MPG, O2 sensor seems okay
> >
> > I'm not certain what the value is in doing that. Mellow Yellow handily
> > passes California emissions testing so I know it's not running rich or it
> > would fail hydrocarbons. And the output of the O2 sensor, sitting as it
> > does right around the nominal value without going very high (rich) or very
> > low (lean) suggests that the ECU is getting useful measurements and is
> > managing to keep the mixture right around stoichiometric combustion. It
> > seems to me that if the engine was running so rich that it would be
> > causing the considerably poorer mileage than what others report (and I
> > don't lead-foot it), then I would expect to see a darn rich mixture all
> > the time and not expect to have to examine the minutiae of the O2 sensor's
> > output to see some hidden richness.
> >
> > At this point I'm pretty convinced that my fuel is not blowing out the
> > tailpipe unburned -- it ain't black, the plugs aren't black, the exhaust
> > never smell rich. I'm moving on to check compression.
> >
> > --
> > 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 7:38 PM pdooley wrote:
> >
> >> Mike, do you have another vehicle with good O2 sensor?
> >> Just scope that one and compare.
> >>
> >> -----Original Message-----
> >> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of
> >> Michael Elliott
> >> Sent: Monday, September 10, 2007 9:22 PM
> >> To: vanagon@GERRY.VANAGON.COM
> >> Subject: Re: My poor MPG, O2 sensor seems okay
> >>
> >> Hi Mark
> >>
> >> I know about meter sampling rates. I grew up with analog meters and
> really
> >> miss how good they were for showing changes in voltage or current whereas
> >> digital meters are piss-poor at that but much better at displaying
> values.
> >>
> >> I could easily hook up the scope, but unless I know what a normal rate of
> >> bounce and range of bounce are, the results won't offer much
> > enlightenment.
> >> --
> >> 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 6:02 PM Mark Drillock wrote:
> >>
> >>> Mike, the voltmeter approach depends on the sampling rate of the meter.
> >>> Using a scope instead gives a more real time reading and also a good
> >>> indication of the cycling rate at which the O2 reading goes from rich to
> >>> lean and back again. Ken's monitor is good for this as well and much
> >>> cheaper besides. Some of us have scopes already so we get to have more
> >>> fun than most, if we care to.
> >>>
> >>> Mark
> >>>
> >>> Michael Elliott wrote:
> >>>
> >>>> 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
> >>>>>>
> >>
> >
> >
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