JK computer sucks - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > JK Wrangler Technical Forum > JK computer sucks

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSavvy Billet LED Tail LightsCurrie

Reply
Unread 02-23-2007, 07:55 AM   #1
strykermp5
Registered User
 
Join Date: Jan 2007
Location: Woodstock, GA
Posts: 158
JK computer sucks

so... i am almost on the red line on the gas gauge... and apparently, i have 45 miles left in the tank... LOL

working for an attorney... i should run out of gas, take a video of the downed vehicle and the computer. Then sue them for misrepresentation of a vehicle... haha


all joking aside, has anyone else noticed this??

__________________
2007 Wrangler Unlimited X
Jeep Green, Black Cragars, Black Windows

Optional Equipment:
M4 (x2)
Sig 226
strykermp5 is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 09:35 AM   #2
boidy7
Registered User
 
Join Date: Nov 2006
Location: Valdosta, GA
Posts: 93
yeah once i hit a quarter of a tank i gotta find gas QUICK!
boidy7 is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 10:04 AM   #3
PJRedd
Registered User
 
Join Date: Sep 2006
Location: Tacoma, Wa
Posts: 38
From the owners manual:

1. Fuel Gauge
The pointer shows the level of fuel in the fuel tank. When
the fuel gauge pointer initially moves to E, for your
safety, approximately 2 U.S. Gallons (7.6L) of fuel remain.

Because it woultn't be safe if E actually meant empty?
PJRedd is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 11:45 AM   #4
redrom01
JCOB-4-LIFE
 
redrom01's Avatar
2007 JK Wrangler 
 
Join Date: Aug 2004
Location: Gardner, MA
Posts: 480
Dont forget that the owners manual tells you how big the fuel tank is. So when I get down to E and only fill up 16 or 17 gallons I know that I'm not actually close to E.
__________________
-Jeep History-
1992 XJ - '00 till '04 - RIP (thanks alot dave)
1995 XJ - '03 till '07 - Sold to the HUB

______o00o
/__l_l_,\____\,__
l_---l_l__l----[ ]llllll[ ]
._(o)_)__(o)_)--o-)_)__

-Current Jeep-
2007 JK Rubi (Steel Blue)
Searching for an MJ

|¯¯l,[___],
l---L--OlllllllO¬
=~~~==oo==
()_) ()_)--<>-)_)
redrom01 is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 12:03 PM   #5
JK_Jeep
Registered User
2007 JK Wrangler 
 
Join Date: Dec 2006
Location: Coal City, IL
Posts: 801
I got lost using the built in compass on my JK, I had my ham radio on the top of the dash above the stereo and the magnet from the speaker of the ham radio messed up the compass and no matter what direction I was facing it always showed SE.

I was driving in cirlces at the mall parking lot for 5 hours before I figured out I wasnt going anywhere
__________________
( )|||||( )

IT'S A JEEP THING!
Quote:
Originally Posted by sierraexplorer
Thanks, if it is that good than I'm sure that they can't sell it in California. Everything else is illegal in this state except the illegalsl
JK_Jeep is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 08:57 PM   #6
XJ2Timer
Registered User
 
Join Date: Dec 2005
Location: Temple, TX
Posts: 740
Quote:
Originally Posted by redrom01
Dont forget that the owners manual tells you how big the fuel tank is. So when I get down to E and only fill up 16 or 17 gallons I know that I'm not actually close to E.
You are closer than you think. Any crud in the tank settles to the bottom as well as any water that separates from the gas. To keep that stuff out of the fuel pump, injectors and engine the pick up tube does not go to the bottom of the tank.

My old '89 Cherokee the gauge was calibrated where when it hit empty I could drive another day around town and not run out of gas. On my '01 Cherokee when the low fuel light comes on I have maybe 5 miles before the gauge needle drops from a sixteenth of a tank to empty. When it hits empty I better be at a pump. I ran out of gas once soon after I bought it. When I filled it up I could only put 17.5 gallons into the 20 gallon tank.

Remember when the computer monitor makers were sued and then had to label the monitors with the actual viewing size of the screen? Wish the auto makers had to do the same. If they claim a 20 gallon tank on my Cherokee than that ought to be 20 usable gallons. Not 17.5. At 20 mpg on the highway I ought to be able to drive 400 miles then run out of gas not 350.
__________________
1st one- 1989 Cherokee Laredo. 12 great years
2nd one- 2001 Cherokee Limited. Got it before they were gone.
XJ2Timer is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 09:00 PM   #7
igofshn
Locked @ both ends
 
igofshn's Avatar
 
Join Date: Oct 2001
Location: Lemoore, CA
Posts: 7,775
Quote:
Originally Posted by XJ2Timer
You are closer than you think. Any crud in the tank settles to the bottom as well as any water that separates from the gas. To keep that stuff out of the fuel pump, injectors and engine the pick up tube does not go to the bottom of the tank.

My old '89 Cherokee the gauge was calibrated where when it hit empty I could drive another day around town and not run out of gas. On my '01 Cherokee when the low fuel light comes on I have maybe 5 miles before the gauge needle drops from a sixteenth of a tank to empty. When it hits empty I better be at a pump. I ran out of gas once soon after I bought it. When I filled it up I could only put 17.5 gallons into the 20 gallon tank.

Remember when the computer monitor makers were sued and then had to label the monitors with the actual viewing size of the screen? Wish the auto makers had to do the same. If they claim a 20 gallon tank on my Cherokee than that ought to be 20 usable gallons. Not 17.5. At 20 mpg on the highway I ought to be able to drive 400 miles then run out of gas not 350.
I have not looked at this fuel pump but on a tj the pick up is at the bottom of the tank. I'm sure this is also.
__________________
2007, 4 door, powered by a minivan engine, locked and riding on 35's.


[Jeep Pics
igofshn is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 10:50 PM   #8
2k2wranglerx
Registered User
2003 TJ Wrangler 
 
Join Date: Nov 2002
Location: pittsburgh, Pennsylvania
Posts: 1,426
i've put over 20 gallons in my tank before.
__________________
93 yj. 355 chevy, heads, cam, intake, etc. 35's, bumpers, winch, lights, and a killer stereo.
2k2wranglerx is offline   Reply With Quote Quick reply to this message
Unread 02-23-2007, 11:36 PM   #9
chevyjeep
Registered User
1952 M-38 
 
Join Date: Jan 2007
Location: Elk Grove California
Posts: 56
Average fuel useage on the computor read 19.2 miles per gallon, but when I do the calculations I get 17.2. anyone else see this problem.
chevyjeep is offline   Reply With Quote Quick reply to this message
Unread 02-24-2007, 12:28 AM   #10
Dr. Internet
Registered User
2012 WK 
 
Join Date: Jan 2005
Location: San Antonio, Republica de Tejas
Posts: 277
I think the fuel sensor used in automobiles was designed by the same guy at about the same time as he designed the water float valve used in toilet tanks. Seriously, it's just a float on the end of an arm that moves across a wire wound resistor. It is barely one step above a hole in the top of the tank that you put a stick into.
I had a 78 CJ that was always at a half tank; didn't matter how much actual fuel was in the tank, it always read half full (or empty for some of you).
So now, I go by the mileage. I average so many miles per tank, and when I get to that number I fill up.
In my new Jeep when the light comes on I have put in anwhere from 13 to 17 gallons.
__________________
Steve

2012 Black Grand Cherokee Overland Summit 4x4
USN Club Hull # WK-13
TEXAS Jeep Club #29
Dr. Internet is offline   Reply With Quote Quick reply to this message
Unread 02-26-2007, 08:28 PM   #11
strykermp5
Registered User
 
Join Date: Jan 2007
Location: Woodstock, GA
Posts: 158
screw it... i put a piece of black electrical tape over...

computer?? what computer?? mine musta not come with one.

oh well!
__________________
2007 Wrangler Unlimited X
Jeep Green, Black Cragars, Black Windows

Optional Equipment:
M4 (x2)
Sig 226
strykermp5 is offline   Reply With Quote Quick reply to this message
Unread 02-26-2007, 09:35 PM   #12
MichaelW
Member
 
MichaelW's Avatar
 
Join Date: Feb 2007
Location: Cartoon City, Nirvana
Posts: 488
Well being from Nevada where there are places with 300 miles between stations. I always carry a full gas can when not in town. I don't use the gage but my odometer as a general rule and never go more than 300 miles between fill ups. Regardless of what the gage may say.

I will be one of the first in line to buy a second tank and transfer system if one comes out for the JK.
MichaelW is offline   Reply With Quote Quick reply to this message
Unread 02-28-2007, 09:17 AM   #13
JeF4y
Registered User
 
Join Date: May 2006
Posts: 254
Quote:
Originally Posted by chevyjeep
Average fuel useage on the computor read 19.2 miles per gallon, but when I do the calculations I get 17.2. anyone else see this problem.
Yep... my computer calcuation must have been designed by someone in marketing. It's off by as little as 2 and as much as 5mpg... most of the time it's 3.5 mpg off... Off to the point that it's totally unreliable from a user perspective.

Great feature

But it should come in handy when people start selling these things used!
__________________
07 Wrangler Unlimted Sahara 4dr 4x4
05 Liberty CRD 4x4 ([b]gone!!! 3/23/07[/b]) - When Jeep gives you lemons....
JeF4y is offline   Reply With Quote Quick reply to this message
Unread 02-28-2007, 11:11 AM   #14
MJS_Jeep_888
Registered User
 
Join Date: Dec 2006
Location: Avon, CT
Posts: 13
From what I've observed personally and read from other posters on a certain JK-specific forum, it seems like the mileage computer takes multiple point-in-time samples of fuel consumption and averages them out --- The problem lies in the sampling timing and limitations; the computer captures only so many inputs (let's say 10, for argument's sake), and overwrites older readings with those new inputs... so in essence, you end up with a "rolling average" of the last 10 (or however many) inputs the CPU recorded...

I've read from some posters (who have let their JKs warm-up in the morning for extended lengths of time) that their mileage reading from the CPU is DRASTICALLY reduced from warm-ups... as for me, if I warm up my JK for 5 or 10 minutes in the morning, I'll see at least a 0.5 mpg drop in the reading the CPU displays.

Oh yeah - one other thing: Most people have observed that the mileage computer gets more accurate when two things happen:
1) the CPU "learns your driving style" and adjusts the shift points to match, AND
2) the engine is fully "seasoned" by 3,000 or more miles of use.
__________________
[FONT="Verdana"][COLOR="DarkGreen"][B][SIZE="3"]*** MJS_Jeep_888 ***
[SIZE="4"] ____ O[/SIZE]|||||||[SIZE="4"]O ____ [/SIZE][/SIZE][/B][/COLOR][/FONT]
MJS_Jeep_888 is offline   Reply With Quote Quick reply to this message
Unread 02-28-2007, 12:31 PM   #15
Jeeples
Registered User
2000 WJ 
 
Join Date: Jul 2006
Location: forum/f310/, UT
Posts: 4,843
Quote:
Originally Posted by PJRedd
From the owners manual:

1. Fuel Gauge
The pointer shows the level of fuel in the fuel tank. When
the fuel gauge pointer initially moves to E, for your
safety, approximately 2 U.S. Gallons (7.6L) of fuel remain.

Because it woultn't be safe if E actually meant empty?

You're kind of correct there.

Modern in tank electrical fuel pumps are made so that the gasoline in the tank provides provides lubricity and a cooling for the fuel pump. Running your system entirely out of gas or even down to the last gallon can cause damage to the pump as the moving parts are not being lubricated properly (just like an engine).

I am going to assume the 2 gallon mark is where the fuel pump is still fully submerged in the tank, thus providing a small safety net for the full pump. Because of this, DCX calibrated the fuel gauge to read empty so that people aren't burning up their fuel pumps within a year of purchase.
__________________
His: '00 WJ 4.7 Limited- stock

Hers: '03 WJ 4.7 V8- IRO 3", 245/75/16 Duratracs
Jeeples is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.