FJ40 gas mileage?

kyle

New member
Let me preface this by saying that I've owned a handful of Tacomas and old Toyota trucks but I don't know jack about FJs.

My friend's brother has a '70 FJ40 that he only gets 9-10 mpg out of. He daily drives it and seeing as how he has a 50+ mile commute, he's not too happy with it. He told his brother that he was gonna consider trading for a Toyota truck or 4Runner with 22R. As it turns out, I have a bone stock '84 4Runner with a rebuilt 22R and he just offered me a straight up trade. It has a stock engine, 4 speed tranny (originally a 3 spd) and 33s. I'm hoping that I can bump the mileage up a bit if I either put the stock size tires back on or regear. I know that it's a 40 year old rig and there are a million things that could have been done to it over the years, but I'm looking for some average numbers here. I only have a 20 mile commute and my 22R only gets 15-16MPG on 31s and stock gears, so I'm seriously considering this truck, but not if I can't get it to do any better than 9-10 mpg.

FJ40 is my dream rig, so I really want it, but I'm not sure about the gas situation. Should I jump on this or pass?
 

Bill Beers

Explorer
Fuelly.com is a good resource for real-world mpg of lots of cars. Unfortunately, the only FJ-40 gas examples I could find were one '73 and two '78s, both in the 10-11.5 mpg range.
 

1911

Expedition Leader
It depends somewhat on how the truck is set-up; which diffs, what size tires, and how good of shape the engine is in. A 1970 40 came with 4.11 diffs, 29" tires, an F engine, and a three-speed tranny, but most have been modified over the years.

My 1980 with 3.7 diffs, 33" tires, a four-speed H41 tranny, and a strong-running well-maintained de-smogged 2F engine gets as high as 14 mpg but 11-12 is much more common, depending on the wind, the hills, and the phase of the moon. I love mine and drive it every day, but you can't worry about mpg or fuel costs with these trucks or it will drive you crazy. If fuel economy is really a big concern, then buy an old beater Corolla or Civic to commute in and drive the 40 for fun.
 

cruiseroutfit

Supporting Sponsor: Cruiser Outfitters
12-14 mpg on the highway @ 65mph and loaded. 9-10 mpg on the highway @ 70mph and loaded :D

I always plan for 10 mpg with mixed driving, on/off road, etc. I'm a heavy build, 4.88's, 35's but I do pick up a bit with the 5 spd. I had an FJ55 (same drivetrain) running 4.11's, 35's and a stock H42 (4spd) and we were rocking 15 mpg out of it on the highway, low teens around town. It was a strong 2F, de-smogged and obviously the rubber overdrive really helped. Downside was obviously the beating the clutch took off-road with the high gearing.
 

fjatheart

Adventurer
1980 2f

10-11 traveling 65mph, Weber 38, MAF header, de-smoked, 33x12.50's, 3.73 gears, 2.5 lift.

Hope this helps!
 

kyle

New member
Thanks for the help, guys! Now that I think about it I'm less concerned over mileage, but admittedly 9mpg is kinda unnerving, but I think the main issue is the big wide 33s on stock engine and gearing. Anyways, we're going to meet up and check out eachother's rigs and the way I see it the ball is in his court, if he wants my 4Runner I'm all over the FJ!
 

Desert Dan

Explorer
I'd keep your 4 Runner. It is a known quantity and gets almost 2x the MPG and therfore you could go on 2x a many trips??
 

RicardoJM

New member
My 71 FJ40 is 4.11 gears, a recently rebuilt F.5 engine with 33X10.5 tires and it is getting around 11 mpg in town and into the mid 13's on the freeway.
 

Rezarf <><

Explorer
I get a consistant 12-15mpg and I have:

35's
4.11's
4 speed
good compression
Jim C. rebuilt carb
FJ60 electronic ignition
patience to keep it timed and tuned and the valves adjusted.

I had a few tanks at 17mpg... a loooong time ago. Can't seem to break the 16mpg mark now. It drops to 10mpg quick when I tow my trailer.
 

cumminscruiser

Adventurer
Fuel economy

My 71 FJ40 with 35's get a dissapointing 18 mpg feeway, it has a '94 Vortec V6. Dissapointing becouse my 87 FJ60 with 35's get 25 mpg freeway, the FJ60 has a 6BT5.9 Cummins. My next engine change for the FJ40 will be a 4BT Cummins Diesel. I hear from a couple of folks get in the 30 mpg range.
 

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