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miltonwaddums
Dodge Dakota
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11/29/2007
19:29:39
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 Subject: Not another mileage question
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Hey all,
I've got a little different mileage question:
Now that cool weather has hit, my mileage in my 03 4.7 4x4 auto has gone through the floor. I easily got 15-16 mixed in the summer. Now I get less than 11 on the same commute.
The only thing to change was that I just got my remote start in. My commute to work is only about 3 miles (all 35mph or slower). Combined with the cold weather and the *ample* use of the remote starter, my mileage blows.
This sounds pretty simple except for the fact that the air around my truck REEKS of unburnt fuel when I go out and get in it in the morning. Is there an O2 sensor issue? Why would it run so friggin rich at idle?
My only mods are a superchips 3715 (91 perf) (which I thought leaned out idle fuel trims) and a k&n drop in.
I know this is another one of those pouting about my mileage threads, but I thought someone may have had something similar happen.
Thanks guys!
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Dan M
Dodge Dakota
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11/29/2007
21:00:56
|  RE: Not another mileage question
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When the vehicle is first started and cold, you're in open loop mode and the o2s are not being used. They don't get used until the engine warms and you go into closed loop mode.
my truck does the same, it's super rich, especially the colder it gets.
- Dan M
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miltonwaddums
Dodge Dakota
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11/29/2007
21:45:41
| RE: Not another mileage question
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Thanks Dan.
I know it runs open loop for a given period. Is it just until the cat(s) is/are warmed up?
I've smelled a rich engine before, but good lord. Thats ridiculous.
Maybe I need to put electric blankets on my cat in the morning. j/k. but seriously.
Glad to know someone else is experiencing it and thanks for the help.
Jay
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brianj
Dodge Dakota
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11/30/2007
01:50:11
| RE: Not another mileage question
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no dan hit it right on the head. its designed to go rely rich to actually warm up the engine quicker.
and its actualy waiting for the o2s to warm up and once there warmed up then the engine can read all the inputs correctly.
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Stick Shift
Dodge Dakota
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11/30/2007
03:35:30
|  RE: Not another mileage question
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Its called "winter gas." It is not as good as in the summer. In the summer the octane rating must be better to prevent pinging. Also if you live in an urban area that has "oxygenated" fuel in the winter to reduce polution; the up to 10% ethanol cuts your mileage. Ethanol also boosts the octane rating, again allowing big oil to sell you lousy gas who's stats are improved by the additive. See http://www.co.missoula.mt.us/EnvHealth/AirQ/Air%20Quality%20Topics/Oxygenated%20fuels/OxyPage.html
I go from 14.7 mpg in summer to 13 in the winter. Same commute, very little additional warm-up time.
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RadioMan
Dodge Dakota
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11/30/2007
06:54:22
|  RE: Not another mileage question
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I had to get my 79 AMC out of storage untill my
02 Dakota is fixed (long story) and I noticed
right away the MPH on the AMC went to the floor
also. It even has a electric choke (remember
those). It gets 22+ to the gallon in the summer
months when I drive it.. Not even close to that
here in NW Ohio right now, plus it's burning a
full tank of *summer* gas.
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RadioMan
Dodge Dakota
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11/30/2007
14:04:35
|  RE: Not another mileage question
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Typo guys... It's not MPH but MPG.
Have a great day..
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Stick Shift
Dodge Dakota
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12/04/2007
06:44:25
| RE: Not another mileage question
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RadioMan, if you just got the AMC out of storage and it has "summer gas", you should expect bad mileage as the lighter components (VOCs) have evaporated or "flashed" off. Now you have "old gas." (the car, not you personally) The rule of thumb I've heard is that gas only mantains its full heating value and octane for 30 days unless you add stabilzer.
AMC: Pacer, Gremlin?
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miltonwaddums
Dodge Dakota
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12/04/2007
07:46:07
| RE: Not another mileage question
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Thanks for your replies guys.
I agree with stick shift on his old gas theory.
To update, I am now getting 13.5 on the same conditions (running my truck in the driveway longer than I drive it to work, and a few errands). Bad gas? The tank I got 10 on was the only one. I almost always get it at the same reputable gas station.
Also, just wondering if maybe it was due to the recent shift to really cold weather (and probably winter gas), and the pcm is/was adjusting for the change? Thoughts?
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Bob Lincoln
Dodge Dakota
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12/04/2007
08:09:46
| RE: Not another mileage question
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If you've only got 3 miles to work, just get in, start it, wait 20 seconds and go. You're blowing most of your gas out while you sit inside, or while you scrape. Sitting still gives you zero mpg.
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miltonwaddums
Dodge Dakota
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12/04/2007
09:38:03
| RE: Not another mileage question
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Hey, I know I'm a pansy, but I like getting into a warm truck and not scraping. Besides, what difference does it make if I have a 20 mile commute or a 3 mile commute? The reason for starting it is to not scrape and being warm for the first 5 minutes, because remote starting or not, it will be warm in 5 minutes. Also, since my commute is so short, I can afford the little bit of extra gas.
I realize that this is a waste of gas @ 0 mpg, but I'm just doing my part to support terrorism (just kidding of course!)
One thing I forgot to mention in my last post is the fact that the *overwhelming* smell of unburnt fuel is gone, and is more like a normal "start-up rich" smell. Could there be anything wrong or shakey with my truck (i.e. bad O2 sensor, IAT sensor or TPS)?
Thanks,
Jay
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Blakdak
Dodge Dakota
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12/04/2007
09:53:16
| RE: Not another mileage question
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I'm going to have to agree with Bob. Can't have it both ways. Either warm truck with very low mileage, or get in and go. The driveway thing is killing your mileage with such a short commute.
Did you have the heater block installed? I run mine for a few hours before starting in the morning (on a timer). Although I'm paying a little more in electricity, I'm still saving some money because of the mileage gain. The truck is in open loop mode for only a very short time. Plus the heater is warm right away.
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miltonwaddums
Dodge Dakota
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12/04/2007
10:18:12
| RE: Not another mileage question
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My original question was that I was abruptly getting 10mpg, after getting 13-14 routinely. Now its back up. I just didnt know why it went down like that. I absolutely agree that running it in the driveway is stupid, but hey, I like it warm.
As for the block heater, I got one free from a buddy who (for whatever reason) had an extra one (brand new in mopar bag). I didnt know if it would be worth the effort to install it and buy the timer, heavy duty extension cord, buy the electricity, etc. It would probably have a positive effect on engine life due to warm oil at cold temperature startups (I'm using full syn. 5W-30). How long do you run it in the morning?
Jay
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Blakdak
Dodge Dakota
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12/04/2007
10:25:49
| RE: Not another mileage question
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I had mine installed at the factory, so it was really cheap. If you have to pay for installation it may or may not be worth it. If it's a DIY, then go for it. I let mine run for 3 - 3.5 hours. It doesn't seem to be any warmer with longer times. Figure I'm spending about $.10-.15 in electricity for each day, but the truck warms up right away and my mileage has increased from last winter w/o it.
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miltonwaddums
Dodge Dakota
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12/04/2007
11:41:00
|  RE: Not another mileage question
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Its a DIY job, so the next (somewhat) warm weekend, I'll install it. If I'm not mistaken, will I need to drop the oil to do this install?
Thanks for your info Blakdak.
Jay
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dude
Dodge Dakota
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12/04/2007
12:31:20
| RE: Not another mileage question
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Factory style block heaters simply replace one
of the frost plugs on the side if the engine block. It's a frost plug with a small electrical element that dips into the coolant.
To install one yourself, you'll have to drain the coolant, punch out a frost plug and drive in a 'block heater' one in it's place (hoping it seals well and doesn't leak)
In below freezing weather, these will help starting but give very little or no heat in the cab.
Some aftermakets ' heater/circulators' can be installed in-line with the heater hoses to also
warm up the cab, but sometimes limited mouting locations/height affect how well they circulate.
These items can be found in 'big rigs' parts catalogs.
As heat rises, the oil below doesn't get warmed up at all.
I myself use an oil pan heater pad, I'd rather have warm oil circulating ASAP durind a cold start.
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