MY fj62 sucks too much fuel!!!!!!!

[RockDoc]

Ditto what everyone has said above.

Tires are probably the biggest offender IME. big and fat = bad mpg. Heavy weight lubes = drag on engine and drivetrain. Low tire pressure in any tire =REAL BIG loss of mpg.

Tune up, air filter, synthetic everything, 2WD, new spark plugs, clean engine internals, clean fuel injectors and carbs; etc, all make a difference.

My mpg dropped 3 mpg when my tires were only 3-4psi under the max of 35. Put as much pressure in your tires as they can stand, and as much as your back can tolerate (the ride).

Really good point on the tire pressure. I try to keep mine around 35psi on the front and 40 psi on the rear. Can't remember what the manual calls for, but worth a look.

When I moved out to Edmonton, we pulled a tandom trailer behind my brother's Dakota. On the first fill, we only got like 8 mpg. After that we boosted the pressure in the trailer's tires to 45 or 50 or something, and it made a HUGE difference.

I think in some ways the reliability of these engines leads to running too long on worn out components. My truck was a bit slow when I got it, but with putzing around and replacing all the tune up stuff, I was really happy with how it woke up. I wouldn't be shocked if it had gone up till I bought it with little maintenance beyond oil, plugs and the oil and air filters. The dizzy cap was horrid when I replaced it.

 

[DirtyLittleSecret]

I routinely get 550 km (340 miles) "usable" out of a tank on the highway. I generally try to stay below 110 km/h (68 m/h). That is with a 2.5" lift, and stock (29") tire size. Driving between school (Edmonton) and my folks place (Brandon), I can do the 525 km to Saskatoon without a fill, but need to dump a jerry can in on the stretch from Saskatoon to Brandon (620 km). When the tank hits about 7 or 8 liters left (about 2 gal) the fuel pick-up gets spotty. (I once made it to about 580km or 590km before the pick-up sucked air on a corner)

I run synthetic everything (engine, ATF, transfer and rear diff), and perhaps the cooler temps up here and night driving help a bit too. Also, the drive is almost dead flat (probably have to drop into 3rd for less than 5 min the whole way), and next to no traffic lights or stop signs, aside from 4 cities you pass through.

It also helps that the ambient air temps are probably colder when you fill up to go. Cold fuel = Dense fuel = More fuel.

 

[TextorFJ62]

Really good point on the tire pressure. I try to keep mine around 35psi on the front and 40 psi on the rear. Can't remember what the manual calls for, but worth a look.

When I moved out to Edmonton, we pulled a tandom trailer behind my brother's Dakota. On the first fill, we only got like 8 mpg. After that we boosted the pressure in the trailer's tires to 45 or 50 or something, and it made a HUGE difference.

I think in some ways the reliability of these engines leads to running too long on worn out components. My truck was a bit slow when I got it, but with putzing around and replacing all the tune up stuff, I was really happy with how it woke up. I wouldn't be shocked if it had gone up till I bought it with little maintenance beyond oil, plugs and the oil and air filters. The dizzy cap was horrid when I replaced it.

What did you replace component wise and how many miles do you/ did you have? Also what does dizzy mean? Sorry for the dumb questions but I really want to improve my mileage as well and I am not familiar with the lingo. Thanks.

--AT

 

[gray]

Textor FJ62:
The "dizzy cap" is slang for the distributor cap. The general points were that a vehicle in good running order will get better gas mileage; so, a complete tune-up, with new spark plugs (Denso), new wires if your old ones have over ~100-150K or so on them, new Distributor cap and rotor, check/set timing correctly (without pinging), clean air filter, clean engine internals (change oil), low weight oil and gear lubes (like Mobil 1 75-90 synthetic in the transfer case and differentials. run a can of BG44K through the gas tank (NAPA), clean PCV valve, clean Throttle Body and intake manifold, no vacuum leaks (bad hoses), etc,etc,etc,

And probably one of the most overlooked of all; check your tire pressure, and keep it as high as you can; do not exceed the max stamped on the tire, but the closer you get to that, the better your mpg will be IME.

 

[TextorFJ62]

Textor FJ62:
The "dizzy cap" is slang for the distributor cap. The general points were that a vehicle in good running order will get better gas mileage; so, a complete tune-up, with new spark plugs (Denso), new wires if your old ones have over ~100-150K or so on them, new Distributor cap and rotor, check/set timing correctly (without pinging), clean air filter, clean engine internals (change oil), low weight oil and gear lubes (like Mobil 1 75-90 synthetic in the transfer case and differentials. run a can of BG44K through the gas tank (NAPA), clean PCV valve, clean Throttle Body and intake manifold, no vacuum leaks (bad hoses), etc,etc,etc,

And probably one of the most overlooked of all; check your tire pressure, and keep it as high as you can; do not exceed the max stamped on the tire, but the closer you get to that, the better your mpg will be IME.

You the man. Thanks for the education. I have about 140K miles and need to do this stuff soon. I always change the oil and tranny fluid regularly so I am good there, but the hoses and other stuff prob needs work. Thanks!!

 

[RockDoc]

What did you replace component wise and how many miles do you/ did you have? Also what does dizzy mean? Sorry for the dumb questions but I really want to improve my mileage as well and I am not familiar with the lingo. Thanks.

--AT

Yup, distributor cap. The lead running from the coil to the cap had a loose connector (compressed and loose fitting) so it had been arcing and basically burned up that part of the cap.

Since I got the truck (~120k miles then, about 165 now) I have done:
the cap and rotor
checked (but not replaced other than the coil to dist. lead) the coil and plug wires
fuel filter (often overlooked, but makes a difference)
plugs a couple of times
have a new PCV valve to put in when I have the valve cover off (make sure this is working properly to keep your oil in good shape
valves adjusted (plan to learn this myself soon so I can do it more often)
I've run Sea Foam through a couple of times to clear carbon out
throttle body cleaned once off, once in place
injector cleaner a few times a year.....

I switched to synthetic oil shortly after I bought it (Mobil 1, I think I'll switch to something else once I get my new filter setup, Mobil 1 isn't what it used to be from what I read, reading more to decide what I want). It seeps a fair bit, but it did before the switch too. Plan to change the oil pan gasket soon, and see how much that cuts it back.
I switched to synthetic in the transfer, diffs and tranny more recently. I would definitely recommend synthetic ATF to keep the A440F happy, but the transfer and diffs is a judgement call (really nice at 30 below though). If your truck sees water crossings, I would stick with dino and change more regularly.
Make sure the air filter isn't overlooked. I used to run a K&N, but pulled that recently after looking into them more. It seemed to help a bit with low end, but I would rather have better filtration......someday the K&N may reappear as a prefilter though, to cut down on what makes it to the paper filter, and keep water out.

blah, blah, blah.....

I really don't think I have enough experience to soap-box on this, but that's what I have done, for what it is worth.

 

[RockDoc]

I had been thinking about changing the oxygen sensors, but given that I seem to be doing alright milage-wise, they must still be working alright.

 

[gray]

Ditto all above, except the Seafoam part. Won't hurt anything, I just use a different method; To each his own poison or potion. Point is, keep the intake and oil clean.

IME, the most common cause for a rough idle, hard starting, and poor performance in this engine is a dirty air filter (assuming you have baselined everything with a complete tune-up). The 3FE engine just does not like a dirty air filter. Change that at least every 7-9K; at least; depends on how dusty your environment is. Almost everytime I thought I needed a tune-up or new plugs, etc (with the 3FE, your engine type) all it was was a dirty air filter, that is, before I switched to the K&N; the OEM were (are) $30 a pop.

I have also used K&N filters for 20+ years; big controversy, some people just think they are the devils work; I have had great performance out of them. Just clean and oil them as instructed and they work, at least for me, for 20+ years. They do wear out, so after about 100,000 miles +/- I replace them.

The Denso plugs are better than anything else, except maybe the DENSO Iridium plugs; I put them in my 80 and it likes them. There are two types; .4mm and .7mm center electrode. Something to consider, just that they are not cheap; about $10 each+/-..

 

[CruisinFJ60]

do a vortec and 5 speed swap

just so happens i know the perfect person to do it too!

 

[RockDoc]

do a vortec and 5 speed swap

just so happens i know the perfect person to do it too!

Or, if you really want good milage, put in a diesel.

As for Sea Foam, that's what I had heard of here on mud, but now I've heard the BG44K stuff is really good (maybe better), so I wouldn't hesitate to try that next time around. Still, there is something satisfying about the smoke screen the Sea Foam kicks out.

 

[sfcruiser]

I get 10/11 city and 13/14 highway @65/70. I once droove 55/60 and I got 100mi on the 1/4 tank, my all time best. By that time we had reached our destination. I was cruising well under 2k rpm. w 31 x 10.5's stock.

 

[gray]

I have also used Berryman's Carb and Throttle body cleaner; it seems to work very well in dissolving varnish and crud in the intake; I spray an entire 20 oz can into the PCV port on the throttle body, and then another full can into the other ports, at least, while keeping the engine running. And don't forget the butterfly, etc. I get smoke also, just not as thick; not sure how much of the SeaFoam smoke is just the SeaFoam, smoking. But as I said; everyone has their own way and if it works, great. Point is, keep the throttle body and intake and cylinders clean and your LC will be happier.

I would love to put in a Vortec or a turbo diesel; just don't have the time or ability to do it myself, and not sure if I would trust anyone tearing into my 62. Maybe a Viper V-10 would work.

 

[archie]

i have 215,000 miles on it. I drive it in the city. I did an oil change and filter, air filter, plugs and i run on 31's.

I get about 200 per fill up in the city with 32's. I fill up when it about less than quarter tank. 210k mine.

 

[2Rusty]

I'm still on my first 3,000mi. since getting my 88-fj62 in Aug. There was quite a bit of work to do to pass insp.,but none involving the eng. I read a post early on that said to just drive for a while and get to know it. One of the first things I did was 33x9.5 tires.I ran a can of seafoam also,and just using the trip meter and gallons it takes upon fillup it's getting 10-11mpg.The truck idle is steady at 800 or so and nice and even.I changed all the fluids and while I use synthetic in my rover and 300td I opted to use dino and change at 3000mi. The oil is still really clean w/2oomi to go.The total when I change it will be 163,000.I should do a tuneup.

 

[sandcrawler]

Another overlooked item in fuel mileage is how far are your typical trips? If they're not far, and the rig doesn't get up to temp, fuel economy will suffer significantly. I saw a significant gain when my commute went from 9 to 19 miles (and all off my vehicles, not just my 62). I suspect that mine needs a another good tune up (last one was about 12-15k ago) but I still get about 13 commuting and 15-16 on highway trips.

 

[PAFJ]

Here you go.

You can use that same formula to figure out mileage, instead of MPH as well.

(new tire diameter/stock tire diameter) * odometer mileage = true mileage.

Thanks!