i know that on the newer chevy trucks, there is a computer that will monitor u're driving style and adjust the power output/fuel consumption on the truck accordingly....

now....i'm on a quest to get better gas mileage so is there anyway i can do this to my truck? i've heard of just unplugging the battery and etc...but i was wondering if it will re-do the adaptive learning thing...i think it takes bout 500 miles to get fully adjusted....plus the guy that had the truck before me...i dont know how he drove...i'd like to start fresh if i could...

 

It is constantly monitoring and learning, making adjustments and such to maintain the best fuel economy and emissions it can. Disconnecting the battery will only make it have to re-learn from scratch. The best way to get more milage to have the engine properly tuned and lubed, tires properly inflated, AC off, 2wd, cover over the bed, and being light on the accelerator helps a LOT.

 

yah, thats what i've been doing, it just seems to me that somethings up....

my engine has good days and bad....mind u that the weather wont be all that different...but somedays it'll haul ***....others it kinda just putts along.....

i just need to find a good price on a soft tonneau cover....

 

i also know that in overdrive, it's considered the "economy" setting, where as o/d off, its more "performance" at least in my case it rev's faster and harder

 

I bet you pay more for the cover than you will save in fuel costs. Drive slower, buy something that is more fuel efficient.

There is a long term and short term fuel trim table. The short term will be adjusted within seconds after you disconnect the battery. The adaptation has nothing to do with the benefiting the driver, it's stricly to keep it in compliance with emissions. All that more power and less power gear related stuff is in your head.

 

Overdrive is basically 5th gear on the autos. This is the top drive gear and has a drive ratio greater than 1:1, meaning the wheels turn more than once for every turn of the engine.. Or atleast the tranny output shaft does, something like that. Point being you should ALWAYS use OD whenever you can. The only times you should turn it off are when you need extra power because you are towing or climbing a very steep hill. Do not consider it a 'sport' mode, even though many car makers will tell you it is. Basically the computer thinks you're towing when you disable OD. So it should shift later and will never use high gear, so yeah, it'll rev more (although never faster, that's a function of the engine). The downside is it will murder your fuel ecconomy, especially on the highway.

Another useful reason for disabling OD is for more engine braking. Say you're coming down a very long steep grade. You keep finding yourself reaching for the brake just to shave off some speed. In that case you can disable OD and use engine braking instead. Be careful doing this in snow though. Most automatics I've seen/used, particularly those in pickup trucks tend to be rather abrupt when they downshift. This abruptness can be enough to cause you to loose traction and spin out in low traction situations (ie snow & ice).

Edit: Oh, and I would tend to agree w/ Dave's assesment of the bed cover. Don't expect much of an improvement. I've had covers on this truck and my last one. I keep a pretty accurate fuel log and I can't show you any improvment w/ or w/o the cover. I do know that it does not hurt fuel ecconomy. It also keeps your groceries quite dry on those rainy days..

 

Thats some good info to know on the OD. Does the same apply to both manual and auto trannys?

 

Well sure. W/ the stick you could drive around in 4th (and lower) all day. As w/ the auto w/o OD, the performance will seem a bit better, and she'll tow better, but mileage will go to hell. In fact 5th gear on my '99 was labeled 'OD' on the shifter. As far as I understand it, that truck had the same transmission as the new one does, although the new truck's shifter is labeled '5'. The new truck is less of a dog in top gear (5th/OD) but it's a 4.0L as well. The '99 was a 2.5L I4.. Anyhow..

 

Mine is labled (D) aswell. So is 5th gear still an overdrive gear for you?

 

Phil, Colin is talking manual transmission with the 5th gear labeled OD in his old truck
new truck still has a 5sp manual but gears are numbers 1-5 where 5th gear is still the OD

 

And yes, it is an overdrive.

Ratios are:

2.3/3.0 4.0
1st 3.72 3.40
2nd 2.20 2.05
3rd 1.50 1.31
4th 1.00 1.00
5th (OD) 0.79 0.79

Automatics are too:

1st 2.47 2.47
2nd 1.85 1.85
3rd 1.47 1.47
4th (OD) or 4th 1.00 1.00
5th (OD) 0.75 0.75

 

I used to joke w/ my friends that 5th/OD was a total afterthought. The truck would've been fine w/ a 4 speed stick. 5th was nice to have to save some gas, but if you had anything resembling a hill 4th was badly needed. At anything below 70 MPH anyhow.. I don't know anything about the development of the trannys, for all I know it was a 4 speed and they just added another gear one rev..
Does that mean it technically has two OD gears? Or is that a typo and should read 4th: (D) or 4th?

 

There are two manual transmissions in the Ranger. The R1 and R1HD. The R1 is for the 2.3 and 3.0 and the R1HD is for the 4.0. The ratio on the left is for the R1 the right is the R1HD. They must have kept the same format when they posted the auto info. That must be why the ratios are listed twice. It is a sloppy paste of a Ranger specifications text file.

I don't know why it says OD for a 1.1 ratio cause by defenition that isn't true. The info is probably 95% accurate over it's 10 pages and not the best organized. The PDF version is much nicer.

 

strated my 1993 2.3 then turned off, now it will crank over ,but no fire.
checked on cumputer said the pcm is bad