FJ40 Gas Mileage.... (1 Viewer)

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Joined
Mar 29, 2019
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Location
Conway, AR
If my math is right, my '76 40 with 2f is getting 8 mpg. I know the gas mileage is supposed to suck, but ….this bad?? Running 32" tires ( i have adjusted for this in my math). Engine is de-smogged. 4 speed with 4.11 gears. Aisin carb and Delco dizzy (installed by one of the PO's). Running non-ethanol 87 octane gas. Compression is running 115 - 125 depending on cylinder. I've adjusted valves also.

I'm no wiz with timing or carb adjustments, but can I expect to get much more by messing with these?

I'm not expecting much out of the rig, i just love to drive it. But would like to resist the urge to gas up at every station I see....
 
Welcome to the awesome 2F engine. You might be able to squeeze a few more MPG but not by much.
 
Yep, the old 'tube' up. That'll do it.

Sorry, I couldn't resist.
 
Stupid iPhone 5 auto correct LOL

I get regularly 12-13

Electronic ignition
Weber 38/38
Tune (or Tube) up every year :)
Header

The worst I get now is around 11 during winter.... sometimes 10 depending on amount I drive in 4

When my engine had 440,000 miles on it I still got 9 ... my compression was WAY worse than yours
 
I added an auxiliary tank and carry additional jerry cans, when conditions dictate. I’m now able to bypass gas stations time-to-time.

I doubt my fuel use is economical, but it sure seems frugal, from a time-spent-filling-up on trips perspective.

:cool:
 
You have to consider the taller tire size in your calculation. 32" tire is roughly 14% taller, therefore add 14% to your distanced traveled via odometer reading. Unless you fill up at gas station A and drive to gas station B and use google maps to calculate distance and divide by gallons used.
 
Thanks for the replies everyone. I've not done a proper "tube" up yet. Need to find someone to help me with that.

I recently went from an old Rochester carb back to the Aisin. If memory serves the Rochester got 9 mpg, but it ran like crap and i wanted the Aisin anyway. The Aisin runs so much better.

What was the original tire diameter in '76? I figured 28" and came up with 12% to add for distance travelled with my 32" tires.

I am going to add several jerry cans in the near future...
 
I’m getting between 12-15 mpg out of my mighty 2F, de-smogged, cammed out, and some other work.

33” rubber.
 
I get 10-11 mpg with my old, worn, trusty F.5

I’m running 35s also...

How much do you “use” the skinny pedal, or do you just “cruise”?
 
I dont use the skinny pedal too bad, i think. Try to go easy on it. Mostly mixed town and highway driving. Ill try to do some more on the highway and see how it does. Got my son coming home next week to help with tune up/carb adjustment.
 
8mpg might be a little low but not much. Owning a FJ40 is kind of like owning a big diesel pusher RV. If you are worried about mileage, you shouldn't have bought it. I wish my diesel pusher averaged 8 mpg!
 
If a tune-up doesn't yield improvement, you could switch to an electronic distributor. FJ40Jim aka TLC Performace of Lancaster, OH recurves FJ60 dissy's. He may even have some ready to go.

The 81-87 ignition is uber reliable because the electronics are not all packed into the hot, vibrating dissy. The finned aluminum heat sink seems to be of benefit also.

The 81-87 ignitor does have variable dwell (like the newest pertronix) and has self protect to keep from frying itself if the key is left on (like the newest pertronix).

The 74-earlier USA and cheapo non-US dissys are copies of a very inexpensive Delco dissy, w/ all attendant durability issues.

Want a hot spark?: open the plug gap. Just that simple.
 
If a tune-up doesn't yield improvement, you could switch to an electronic distributor. FJ40Jim aka TLC Performace of Lancaster, OH recurves FJ60 dissy's. He may even have some ready to go.
I may give him a ring. I want to get rid of my Delco Remy and go back to Toyota dizzy at some point
 
Though, comparing tire height and calculating percentages could work OK for calculating odometer correction. I believe there are 2 different ways that are probably more accurate. 1st your odometer works by measuring revolutions per mile. Measure the circumference of the stk tire and divide that number into 5280. Then do the same for your 32" tire. Better yet is to mount each tire to the 40 and roll the tire 1 revolution and measure the distance traveled, and ÷ that # into 5280. Doing it this way takes in acct for the contact patch of the tire. You'll have to measure stk and 32" tire to get percentage correction. Now for the easy way. Use the mile markers on the highway. Note the odometer reading while passing a mile marker, travel 10 miles per mm and note the odometer reading and Calculate your findings. I like to use 10 miles, because it averages out government inaccuracies. Do it a couple of times to confirm your numbers.
 
Though, comparing tire height and calculating percentages could work OK for calculating odometer correction. I believe there are 2 different ways that are probably more accurate. 1st your odometer works by measuring revolutions per mile. Measure the circumference of the stk tire and divide that number into 5280. Then do the same for your 32" tire. Better yet is to mount each tire to the 40 and roll the tire 1 revolution and measure the distance traveled, and ÷ that # into 5280. Doing it this way takes in acct for the contact patch of the tire. You'll have to measure stk and 32" tire to get percentage correction. Now for the easy way. Use the mile markers on the highway. Note the odometer reading while passing a mile marker, travel 10 miles per mm and note the odometer reading and Calculate your findings. I like to use 10 miles, because it averages out government inaccuracies. Do it a couple of times to confirm your numbers.


Or download an app.
 
anything under 10mpg strikes me as low - well-tuned, my desmogged 2F runs around 15mpg or better on longer drives, but I haven't really much counted dollars or miles at all in how I use my 40 - it's all in the "smiles per mile" for me :steer:
 

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