1999 jeep wrangler 4 cylinder auto 3 speed it sucks in gas milage. Question is can I put a bigger trany in it. did a tune up not really helping daily driver please help
trans question
- Thread starter johnny
- Start date
How long do you think it'd take to recoup the costs of installing a different transmission by the possibility of very slightly improved fuel economy? My thought on that is pretty much never would you recoup the costs of installing that different transmission. Not that I believe your poor fuel economy is the fault of your 30RH automatic transmission.
What size tires are you running, what air pressure is in them, and if they're significantly larger, have you regeared your axles so they're more appropriately geared? Bigger tires without regearing the axles will harm the mpg too.
How is your upstream 02 sensor? Have you ever replaced it? The upstream 02 sensor can go bad (they always need replacing at some point) and cause the fuel-air mixture to go full-rich which will destroy your mpg and reduce engine power.
What size tires are you running, what air pressure is in them, and if they're significantly larger, have you regeared your axles so they're more appropriately geared? Bigger tires without regearing the axles will harm the mpg too.
How is your upstream 02 sensor? Have you ever replaced it? The upstream 02 sensor can go bad (they always need replacing at some point) and cause the fuel-air mixture to go full-rich which will destroy your mpg and reduce engine power.
Here's an idea of what your stock mpg should be:
https://www.fueleconomy.gov/feg/bymodel/1999_Jeep_Wrangler.shtml
https://www.fueleconomy.gov/feg/bymodel/1999_Jeep_Wrangler.shtml
You're getting worse than those numbers? Wow...
I'm going to say if that's the case it's likely one of two things:
1) Driver error (knowing how to drive a car to get the best mpg out of it is always the number one reason for poor mpg)
2) Your engine needs a tune up
If it's not driver error I'd be willing to bet your engine needs a tune up... New plugs, cap, rotor, O2 sensors, etc.
Make sure there are no check engine lights or anything along those lines. An engine that has been maintained in a while can really start to affect it's performance.
I have done plugs and wires I guess it time to do the rest and I am not hotroding or anything like that just trying to figure it out it my first jeep thanks for the advice
no lights at all and last time I filled up at 150 miles then did a tune up now its at half a tank almost 80 miles
I did a highway trip with my Wrangler that has a 4" lift and 33" tires. I was able to do 200 miles and get there with a little under half a tank on the fuel gauge.
Of course that was all highway driving though...
Of course that was all highway driving though...
Using the fuel gauge to determine mileage is like using the National Enquirer to set US foreign policy, it is just a very bad idea. Learn how to calculate mileage by resetting the odometer trip meter at each fill up against the number of gallons pumped. Get in the habit of topping off the tank the same way each time so you get a consistent fill level.
TJ fuel level gauges are notoriously inaccurate and the number of miles from full to 1/2 is never the same as 1/2 to empty especially when you consider that most of them will run at least 75 miles after the needle touches the E and most will take only 14ish gallons to fill the 19 gallon tank at that point.
Also, you need to drop the tank and see if it has the 15 or 19 gallon tank. The difference is the length of the filler tube inside the tank being longer to limit the fill level to 15 gallons. If so, you can cut it off using one of the various methods documented online to achieve the full 19 gallon fill capacity.
For example though, if you do have the 15 gal tank and it has the same safety buffer that the 19 does which is 5 when it touches E, then that leaves 10 of which half is 5 and 80 miles burned for 5 gallons is 16mpg which ain't too shabby. All speculation of course but done so to illustrate that without knowledge of what is being burned in X number of miles, you have no idea how good or bad the mileage is.
If you want to know how many gallons the tank holds the easy way, toss a full gas can in the rig and keep driving until the tank is empty. Put enough in to get you to a gas station and fill it up from there. Add the number of gallons you put in with the gas can to how much you put in with the gas pump and that will give you an idea of how big the tank is. Go from there.
Also, you need to drop the tank and see if it has the 15 or 19 gallon tank. The difference is the length of the filler tube inside the tank being longer to limit the fill level to 15 gallons. If so, you can cut it off using one of the various methods documented online to achieve the full 19 gallon fill capacity
so how do I go about doing this or finding it out online
so how do I go about doing this or finding it out online