Date: Sat, 1 Dec 2007 10:39:04 -0800
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: New thermostat funky?
In-Reply-To: <71d9cdf90712011023k79fd6b03i629232ccf519ea31@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Tenterhooks? Hanging on to my every word, I bet! I have learned to keep my
posts simple and single-subject to avoid spinning off into a thread
unrelated to what I was asking about. In this case, the engine temp.
On the downhill, the engine was cool enough to cause the ECU to go into
open loop, as mentioned. You're right: when closed-loop, the O2 monitor
would normally go off-scale in the lean direction with the foot off the
gas and the engine spun up by the transmission. But when open loop, the
injectors dump in some predetermined amount of fuel, which I saw on the
monitor. So the engine wasn't not generating heat.
I guess I better crack the Bentley's -- where is the dash temp gauge
sensor located, anyway? I was running the heater, maybe there simply
wasn't enough waste heat left over to dump into the radiator.
So I reckon the question is whether this is normal behavior: would long
downhill in 35F - 55F weather, with the heater on, result in an engine so
cool that the ECU goes open loop and the temp gauge rides only about 1/3rd
up from the full-left dead cold setting?
As for mileage, there is an improvement. Can't say exactly what made the
difference. My Mount Laguna trip is once a month (had to skip last month
due to fire closure), so I'd rather not try one thing at a time to see
what makes a difference as life is too short, esp. at my age.
City mpg pre wheel alignment(but post changing timing and some other
fussing about): 13.7 mpg
City mpg post alignment: 15.6 mpg.
Mount Laguna run pre-alignment (and pre all that other stuff): 16.7 mpg
Mount Laguna run post-everything: 17.9 mpg.
The rear wheels are still not aligned -- the shop didn't know how. I'll
get that handled before the next run.
--
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 12/1/2007 10:23 AM Jake de Villiers wrote:
> The new thermostat obviously has a lower opening temperature than
> your original or it wouldn't have moved where the needle rides on your
> existing gauge. That may or may not be a good thing.
>
> I'm wondering how the engine could possibly make any heat on a long
> downhill on overrun if the fuel cut-off switch has taken the gas out of
> the combustion chambers. I mean, its damn cold outside and you're
> pumping that air through the engine and there's no combustion. Ergo,
> you're freezing your ass off. :)
>
> Maybe you'll need to idle your way down those long grades to keep
> the water temperature up.
>
> How was your gas mileage? We're all on tenterhooks..........
>
> On Dec 1, 2007 9:33 AM, Michael Elliott <camping.elliott@gmail.com
> <mailto:camping.elliott@gmail.com>> wrote:
>
> A couple months ago I replaced the water pump -- it was making an
> ominous
> grinding noise. Felt crappy when it was removed, too. Installed a
> new Temp
> II sensor and thermostat at the same time. The thermostat came from
> one of
> the usual online presences, can't recall exactly who but could find
> out if
> it's relevant. The packing list noted that it was one that was set
> for 10
> degree cooler than stock.
>
> Indeed, with normal city driving at outside temps in the 70F range, the
> temp gauge seems to rest just at the left edge of the LED whereas
> previously it rode straight up, bisecting the lamp.
>
> This morning I just returned from a two-night camping trip in the San
> Diego mountains. It was 35F this morning and the first 2/3rds of the
> drive
> are mostly downhill, a 6,000 ft elevation drop in about 60 miles.
> For most
> of the downhill portion, the temp needle sat between the painted
> "box" at
> the left-hand side of the meter face (this is a 1984 1.9L) and the left
> edge of the LED, mostly closer to that painted box than the LED. In
> other
> words, at about halfway between left (dead cold) and straight up.
>
> The engine was so cool that the ECU went open-loop during long
> downhills
> (auto transmission in "2," holding road speed down), as determined
> by the
> Ken Lewis O2 monitor.
>
> Once I got to the flats, in 55F temp, freeway speeds of 70 mph or
> so, the
> needle rarely kissed the left edge of the LED.
>
> This is new behavior, I'm not used to seeing the engine run that cool. I
> know that a thermostat with a cooler set point may make it run
> cooler when
> it's not being worked hard, but it should keep the engine warm. I can't
> recall seeing the coolant that cold during downhills. That said,
> this was
> the coldest weather I've made that run in. But still.
>
> Next month I'll make the same trip, and it could be 20F cooler. I
> want to
> be certain that the thermostat isn't, like, stuck open or anything.
>
> --
> 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
>
>
>
>
> --
> Jake
> 1984 Vanagon GL
> 1986 Westy Weekender "Dixie"
> Crescent Beach, BC
> www.crescentbeachguitar.com <http://www.crescentbeachguitar.com>
> http://subyjake.googlepages.com/
| 
