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-   -   What is your YJ MPG (https://www.wranglerforum.com/f290/what-is-your-yj-mpg-1916385.html)

TheHappyJeeper 12-22-2016 02:31 PM

What is your YJ MPG
 
Hey, I have a 1990 4cylinder YJ. I have recently been keeping track of my mpg. I was surprised to find that she only gets around 13mpg for a 4cylinder. Is this normal? Anything I can do to increase it? What does your 4cylinder YJ get?

IRQ 12-22-2016 02:48 PM

16-18 when it was tuned up, running all synthetic oils.

Our jeeps never had good mpg even off the lot I think it was City 17/Hwy 18, remember your driving a box with wheels :)

If it makes you feel better the new JK's get about the same mpg as our 20+ year old YJ's or less when they get done adding a 1000lbs + of bumpers & tires and use it to commute haha

Instructor9 12-22-2016 07:53 PM

9 Attachment(s)
My old JKUS (3:21 manual, Extreme HD front bumper and ACE rails, w/ 31" Bridgestone Duelers) regularly got 20-22.
Have had my 89 YJ (4.2 carb, manual, w/ 32" Duratracs) for two weeks tomorrow. Average 13.6 so far.
Meh, the JKUS was the family vehicle.
The YJ is our hunting/fishing/camping/snow vehicle, so, doesn't really concern me.

9T4YJ 12-23-2016 10:52 PM

I don't know how, but I managed to average about 16.5 mpg driving out to Pennsylvania over the summer. Driving about 65mph on 35's with a 4.0L.

KyleB1996 12-26-2016 10:13 PM

I usually get somewhere in the 14-18 mpg range even geared down to 4.11 with 32" tires and a 4.0 engine.
I think I set the record for a yj by somehow getting 24 mpg on the highway once... But that was probably because I was following a semi tractor the whole way.

MudMagnetYJ 12-27-2016 12:11 AM

Beat you all. Got 30 going 250 miles down South, following a Chevy 1500.

I normally get 17 though. And yes, my odometer is spot on. I clocked my speedo with a GPS and it is scary accurate.

macr0w 12-30-2016 09:43 AM

My 88 258ci six is terrible.

New carb new HEI and I am probably not even getting 12mpg right now. :blackeye

johnsonken1332 12-30-2016 05:42 PM

18-20 stock.
10 stock 3.07gears 35,37,38,40s
8 4.88 gears 37s
But ive always drove it like a dumbass

Luckymac 12-30-2016 05:48 PM

Quote:

Originally Posted by macr0w (Post 28468170)
My 88 258ci six is terrible.

New carb new HEI and I am probably not even getting 12mpg right now. :blackeye

Same for me. I just haven't taken the time to dig into why.

Mostly running back and forth to town and back. With the 31s in 5th gear on the freeway it should do better. At least with a tail wind.

Good Luck, L.M.

Airslot 12-30-2016 07:38 PM

4.0 on 31s. Average 16.5.

macr0w 12-31-2016 09:25 AM

Quote:

Originally Posted by Luckymac (Post 28473258)
Same for me. I just haven't taken the time to dig into why.

Mostly running back and forth to town and back. With the 31s in 5th gear on the freeway it should do better. At least with a tail wind.

Good Luck, L.M.

Yeah, I have 31"/10.50" and stock gearing.

It pulls fine but it drinks the gas.

It still runs kind of rich as well. :facepalm:

Luckymac 12-31-2016 10:59 AM

When I first got it a little over 3 years ago the poor Jeep suffered from the PO not wanting to "put any more money into an old car". It needed a starter and brakes just to make it go and STOP. The top flapped so bad that I couldn't hear the engine squeal from an intake manifold leak and it ran like crap. It had real good tires, no rust and cost me $2K.
Through the first couple months I got it running good, fixed the most glaring defects and made it cosmetically acceptable. Then I got after the mods.

New BBD carb and a HEI did wonders. At my altitude (about 6500') I had to rejet the carb and now I don't get soot blowing out the exhaust when I start it.
If I had more mechanical experience I would be able to set the carb for better mileage.
I think I will try to find a local mechanic that I can trust that has experience with carburetors. Most mechanics today are familiar with fuel injection and to them carbs ate antique technology.

If I come up with a solution I will start another thread called "Better BBD Mileage"

Good Luck, L.M.

P.S. Yes, stock gearing. Next mod is an 8.8 and regear to 4:10. That might help with the DD driving.

macr0w 12-31-2016 04:05 PM

I got my 88 YJ in 89 as a used vehicle with a couple thousand miles on it.

Been a daily driver ever since.

When it's running. :lmao:

I still love it. :)

sccritterkiller 01-01-2017 05:36 AM

I get about 14, but I am running an oversized intake and carb and stock gears on 32s.

Ov yj 01-01-2017 01:28 PM

I run a 4.5l stroker in my 91, 5 speed and 33s. Stock cam and fuel injection. I get 12-14 around town, and 16-18 highway. My stock 4.0 did about the same.

TigWizard 01-01-2017 08:57 PM

My 91 2.5 (stock) gets just under 17if I obey the shift light. When I just drive by "instinct", it's about 15.

Tom95YJ 01-04-2017 11:08 AM

I average 15.9mpg in city. 89 4.2 weber 38/38, hei distributor 4.56 gears and 35 on ethonol free gas

dsaylor 01-06-2017 08:31 AM

This summer, with a new HEI and plugs and wires, I peaked at a little over 13 mpg, running mid-grade gas. Since then, I have installed a new exhaust, fuel pressure regulator, removed many excess lines, gone back to 87 octane, and my mileage has dropped noticeably. My last fill up it was a little over 8 mpg. I cannot figure out what the problem is. My tires are inflated, I've disconnected the FPR, my timing is set at around 8*, and the engine isn't making any noticeable noises indicating that it's running poorly, aside from a cold weather tick that goes away when the oil warms up. Perhaps it's the cold weather, or perhaps I should try mid-grade again, but it hasn't had this low of mileage since I had a leak at the filler neck.

Trauma 01-06-2017 11:00 AM

I have a 89/4.0 and 91/2.5 - the biggest tip I can give on mileage, is accelerate slowly/smoothly, shift sooner, and skip gears - i.e. 1st to 3rd, 3rd to 5th. You can easily do that on flat surfaces if just putting around town.

tashley680 01-13-2017 07:35 PM

My 1990 2.5L 5 spd 4.10 gears all stock (except 75R 235 15s on stock rims) averages 14.5 mpg

DieselDonkey 01-13-2017 08:29 PM

My 90 4.2 5spd 3.07 and 31's averages 10mpg with a messed up carter carb. I'm hoping the mc2150 and hei will improve it.

RoughWaters 01-13-2017 10:12 PM

I was in the 16-18 range consistently in my 95 running 35-12.5R Mud Terrains.

medalguy 01-15-2017 09:58 PM

I drive a stock 95 2.5 with 30 inch tires. I average about 16 mpg which I don't think is too bad. Doesn't matter anyway because it's my favorite drive.

Flight326 01-16-2017 09:57 PM

I also have a stock 95 with 30" tires. I recently drove it on a long road trip about 700 miles and got a good sense for mpg on the highway. It got between 16-18 depending on headwinds. Yeah a headwind made a huge difference on performance, it isn't the most aerodynamic vehicle, that's for sure.

rubiman1969 03-25-2018 09:14 AM

Thread revival
I have a 1987 Laredo 137k stock 4.2 with original Carter carb - stock 3spd auto - stock 3.55 gears running 30x9.50r15 tires on the stock alloys. I'm getting around 14mpg mix of highway and town driving and on regular e10 blend gasoline. I'm about to give it a tuneup and might squeeze a little more out of it

dsaylor 03-25-2018 02:35 PM

I average 10-12 depending on the weather and how much city driving Iím doing. Itís 1 mike to work with 3 stop lights, which Iím sure is bad on my mileage. Iíve got a Weber 32/36, CRT HEI, Holley FPR, and relatively fresh plugs. Iím about to rebuild the carb and do a sea foam treatment and see what happens. 4.2, auto, 110,000 miles. Stock suspension, 1 inch body lift.


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Batjac 03-26-2018 12:35 PM

Man this is depressing me, I'm lucky to get 12 with a stiff wind at my back and I have a new carburetor on mine auto transmission and stock tires.

dsaylor 03-26-2018 12:45 PM

I just realize I commented twice on this. My situation seems to have changed a little since last time. Ha ha


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rubiman1969 03-26-2018 05:05 PM

Quote:

Originally Posted by Batjac (Post 33052169)
Man this is depressing me, I'm lucky to get 12 with a stiff wind at my back and I have a new carburetor on mine auto transmission and stock tires.

You running the ethanol gas in that 4.2 as well?

Raoul 03-26-2018 05:40 PM

Quote:

Originally Posted by rubiman1969 (Post 33039617)
Thread revival
I have a 1987 Laredo 137k stock 4.2 with original Carter carb - stock 3spd auto - stock 3.55 gears running 30x9.50r15 tires on the stock alloys. I'm getting around 14mpg mix of highway and town driving and on regular e10 blend gasoline...

My '90 is a 5spd otherwise same vehicle/results.

I put in a Motorcraft 2100 and did the Nutter bypass mainly because I had a 700 mile road trip coming.

My gas gauge has never worked so all gas calculations were paper and pencil.
I was scared of running out on the interstate but every time I stopped I couldn't squeeze in what I thought it should take.

When I reached my destination found I was getting 20mpg highway.
(55mph up the hill/65mph down the hill)
I don't use it on the highway so now I'm back in the 15 range.


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