Jeep Wrangler Forum

Jeep Wrangler Forum (http://www.wranglerforum.com/)
-   TJ General Discussion Forum (http://www.wranglerforum.com/f282/)
-   -   20 mpg on my tj!!! (http://www.wranglerforum.com/f282/20-mpg-on-my-tj-239322.html)

ChaddG 04-30-2013 05:01 PM

20 mpg on my tj!!!
 
I cleared the adaptive memory, went through the 50 starts in 200 miles, filled up with premium, and got 20 mpg!!!!! :eek: I only ran the tank down the first 5 gallons. got 100 miles to those 5 gallons. :thumb:

I lost the thread, here is how I remember it going.
disconnect the + battery terminal,
touch the + terminal to the - terminal,
turn the ignition on,
turn the lights on,
turn them off,
turn the ignition off,
reconnect the + terminal.

Water Dog 04-30-2013 07:57 PM

I've gotta ask....how do you know you only ran 5 gallons out of the tank?

tjjeepman2002 04-30-2013 08:00 PM

Please do. I run 35's with 4" lift and average 10-13 mpg

RevCo666 04-30-2013 08:07 PM

I own the same jeep as the OP (2001 60th anniversary edition) so I'm curious too now. Only running 31's with no lifts ect.

mrpotatohead 04-30-2013 08:12 PM

Only time i saw numbers that high was using ethanol free fuel across the Mojave and great plains

tjjeepman2002 04-30-2013 08:14 PM

I will try the instructions at begining of thread and see what happens. We may have the best news in town.

chemicaljeep 04-30-2013 08:19 PM

what is clearing adaptive memory? where did you her of this and what does it do to the jeeps computer? wont' connecting both terminals together hurt the system . sorry for so many questions but am interested in this thread.

PStov98TJ 04-30-2013 08:23 PM

Quote:

Originally Posted by mrpotatohead (Post 3703363)
Only time i saw numbers that high was using ethanol free fuel across the Mojave and great plains

I don't even get that with 87 non-ethanol with 33's

mrpotatohead 04-30-2013 08:26 PM

I tracked the original thread down and nobody else really claimed any gains

http://www.jeepforum.com/forum/f13/p...-clear-529400/

ChaddG 04-30-2013 08:41 PM

I know I ran 5 gallons down, only after I filled it up. I drove for 100 miles and filled it.
Thanks for the refresh on the adaptive memory.
I am running 30" tires.
My speedo is off by 2.5 mph. when I am going 67.5 on the speedo I am going 65 on the radar signs and the gps.
would that mean I got better gas mileage? Probably.
I had to read up on the adaptive memory and it had <I'm assuming> 10 years worth in it.
The gas was a 10% ethanol blend.
When I bought the jeep I was getting 13 mpg.
I did the usual tune up stuff, plugs, rail, filters, alignment, and gained about 3 mpg.
I live in wisconsin and the winters are brutal on gas mileage, now it has warmed up and I am almost certain that has a ton to do with it also.
I hurt nothing when I touched the terminals together. no sparks, no complete circuit.
Good luck guys.

tjjeepman2002 04-30-2013 08:52 PM

Quote:

Originally Posted by ChaddG (Post 3703507)
I know I ran 5 gallons down, only after I filled it up. I drove for 100 miles and filled it.
Thanks for the refresh on the adaptive memory.
I am running 30" tires.
My speedo is off by 2.5 mph. when I am going 67.5 on the speedo I am going 65 on the radar signs and the gps.
would that mean I got better gas mileage? Probably.
I had to read up on the adaptive memory and it had <I'm assuming> 10 years worth in it.
The gas was a 10% ethanol blend.
When I bought the jeep I was getting 13 mpg.
I did the usual tune up stuff, plugs, rail, filters, alignment, and gained about 3 mpg.
I live in wisconsin and the winters are brutal on gas mileage, now it has warmed up and I am almost certain that has a ton to do with it also.
I hurt nothing when I touched the terminals together. no sparks, no complete circuit.
Good luck guys.

So by doing this you went from 13 to 20 mpg?. you say you touch the positive terminal but no connection. So basically you ereased all memory?...

Rubicondon53 04-30-2013 09:14 PM

I'm listening in..

Gold Miner 04-30-2013 09:22 PM

just like this
http://i5.photobucket.com/albums/y18...ps772fd069.jpg

Big Sarge 04-30-2013 09:22 PM

Quote:

Originally Posted by ChaddG (Post 3703507)
I did the usual tune up stuff, plugs, rail, filters, alignment, and gained about 3 mpg.

What filters and rail are you talking about? Fuel filters in TJ's next to never need replaced and the fuel rail? (my assumption) is everyhting but a "usual tune up" item. And how many of those three MPG do you think were a result of the alignment? Might be doing an alignment tomorrow boys! :popcorn:

ChaddG 05-01-2013 05:20 AM

sorry I was so vague, I had to get to work.
I replaced the spark plugs, plain old autolite plugs, gapped to .035, or whatever the spec in the book says.
I replaced the spark plug rail, no wires on this model.
I replaced the old air filter with a K&N stock replacement model.
I replaced the tranny filter and fluid.
made sure it was aligned properly at a shop. <has lifetime alignment from tires plus> <<good package to invest in with these beasts>>
Had them re-balance all 4 wheels, <another lifetime balance and rotate deal that is worth its weight in gold.>
New brakes in the front.
New radiator, thermostat, waterpump.
New shocks all the way around.
Took off the hard top and went soft top.
Used premium gasoline, 10% ethanol.

here is what I did with the battery.
1. Disconnected the + battery terminal and touched it to the - battery terminal. let it hang after that.
2. Turned the key to the run position, with the + terminal still off.
3. Turned the lights on.
4. Turned the lights off.
5. Turned the ignition off. <took the key out>
6. Re-connected the + battery terminal.
7. started the Jeep and drove it gently making sure the temp. got up to at least the first hash mark on every drive.
8. Repeated this 50 times for about 200 miles.

ChaddG 05-01-2013 05:23 AM

Gold Miner, yes, Just like that! Lmfao!

ChaddG 05-01-2013 05:27 AM

yes, when I got the Jeep with 85000 miles on it, I was getting close to 13 mpg average, city and highway driving.
taking 2 kids to school in the morning, picking them up in the afternoon, all city.
Then going to work and back during the night. All highway.

MarkGLHS 05-01-2013 06:49 AM

good work. i'll second the OP's experience getting these kind of fuel economy numbers. last summer, with the hard top off, on several 60 mph (never over 65 mph) highway jaunts i saw 20-21 mpg with my 100% bone stock TJ. I did over-inflate the tires to 32 psi (29 is recommended). the worst all-highway MPG i ever got with this Jeep is 18.5 and i attributed that to going 65-68 mph on that trip.

Neil F. 05-01-2013 07:05 AM

"Used premium gasoline, 10% ethanol"

Note this does nothing for you except waste money. Read up on octane level and what it means. The TJ motor only requires regular. Octane is a measurement of resistance to ignition and is only necessary to prevent detonation and preignition. Higher octane gasoline is harder to burn and can actually hurt mpg a little.

Neil F. 05-01-2013 07:11 AM

Quote:

Originally Posted by ChaddG (Post 3703507)
IMy speedo is off by 2.5 mph. when I am going 67.5 on the speedo I am going 65 on the radar signs and the gps.
would that mean I got better gas mileage? Probably.
.

Just the opposite. If your speedo is reading fast, the miles on the odometer are reading more than actually driven. If you are using the odometer to calculate, you are using a number (of miles driven )that is more than actual. Now the amount you state you are off is only about 1% so it insignificant

Rubicondon53 05-01-2013 08:49 AM

Quote:

Originally Posted by Neil F. (Post 3705121)
"Used premium gasoline, 10% ethanol"

Note this does nothing for you except waste money. Read up on octane level and what it means. The TJ motor only requires regular. Octane is a measurement of resistance to ignition and is only necessary to prevent detonation and preignition. Higher octane gasoline is harder to burn and can actually hurt mpg a little.

What you have stated about the characteristics of premium gasoline is true, however non-ethanol regular in our area is 30 cents more per gallon than ethanol regular. With non-ethanol I do get 4 more MPGs than ethanol.. At 4.00 for non it costs 23 cents per mile , with e it is 26 cents per mile... If I can't find regular with non ethanol, but premium is available with non ethanol, I'll put the premium in. Fortunately there are only a couple of states where non ethanol regular is not available.. It doesn't sound like a lot of money, but that 3 cents per mile while traveling long range, means the difference between eating at a good restaurant or sucking up and eating crap at a fast food roach hotel.. ;)

wranglerbob1 05-01-2013 09:02 AM

Confused....If the POS is just hanging there and NOT connected then what is the point of turning lights on and off????? There is no circuit.
Is it like put your left leg in, put your left leg out-shake it all about?????

Neil F. 05-01-2013 09:22 AM

Quote:

Originally Posted by wranglerbob1 (Post 3705410)
Confused....If the POS is just hanging there and NOT connected then what is the point of turning lights on and off????? There is no circuit.
Is it like put your left leg in, put your left leg out-shake it all about?????

There are capacitors associated in the PCM that store a charge. Turning the key on, turing the lights on and touching the cable etc will dischage the capacitors and erase all memory. I have not done it with the Jeep but I can tell you with my other Chrysler product (99 Durango) disconnecting the battery and turning on the key vs just disconnecting the battery causes it to run very differently (common knowledge on Dakota/Durango/Ram boards). I have done it many times.

Just disconnecting the battery - on start up it starts and runs normal

Turning the key and holding 30-45 seconds - on start up it takes longer to fire and runs rough for a for 30 seconds or so

fourty4magjr 05-01-2013 09:27 AM

Hmmm...

n00g7 05-01-2013 09:44 AM

3 Attachment(s)
Quote:

Originally Posted by ChaddG (Post 3704917)
l.

here is what I did with the battery.
1. Disconnected the + battery terminal and touched it to the - battery terminal. let it hang after that.
2. Turned the key to the run position, with the + terminal still off.
3. Turned the lights on.
4. Turned the lights off.
5. Turned the ignition off. <took the key out>
6. Re-connected the + battery terminal.

7. started the Jeep and drove it gently making sure the temp. got up to at least the first hash mark on every drive.
8. Repeated this 50 times for about 200 miles.

You did all this EVERY time? I'll gladly open my wallet.

ccecil3155 05-01-2013 09:55 AM

Doing that 50 times? Who the hell has that kind if time?

I find it very hard to believe that you are getting 20mpg, I just don't see how at all. I can understand 18ish if you only drive on the highway....20 idk

Neil F. 05-01-2013 09:58 AM

Repeated this 50 times for about 200 miles.

So you did this about every 4 miles on average?

SHADYDC 05-01-2013 10:21 AM

im not bashing but i think this is lil far fetched, and if you calculated your milage during this every 4 miles stop its not going to be good reading, need to measure it over few tanks to see consistant readings

Rubi513 05-01-2013 10:26 AM

I was doing some research on my 42 rle about a year ago and stumbled on to something like this. It was supposed to help the transmission shift better by learning your driving style. I tried it. It still shifted too early and my mpg is still around 13. But I didn't do it 50 times either. By only filling up with 5 gallons, he is not getting an accurate reading. How many times have you tried to totally fill up your jeep and the pump cut off, but your were able to squeeze another couple gallons in it? If you add another gallon to his 100 miles, now your only getting 16 mpg.

Rubicondon53 05-01-2013 10:41 AM

I too am highly skeptical of this whole idea.. Manually fooling the computer to do what? Run the engine leaner? If that's the case it would loose a lot of torque and HP.. Everytime you have a headwind, or slight grade, you would be downshifting and loosing any gains in MPG.. The trucking industry learned this long ago.. These motors are governed, but they stopped cutting back HP and torque a decade ago. With Old school thinking they believed turning them back would save fuel, just the opposite happened, weaker engines under load burn more fuel.,. Try dragging a trailer with the 2.5 litre motor,, lots of driving time in 3rd and 4th gear equals very poor MPGs .... Even if this procedure worked, which I doubt, there would be no real world benefit.,


All times are GMT -5. The time now is 06:46 PM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.