6mpg from a 3fe!!! What gives!!!! (2 Viewers)

[jakesiar]

I also swapped out my t-stat (OEM) and the o-ring was not seated properly causing my MPG's to be affected. Ordered a new o-ring and so far all is good. My temp gauge worked properly but then seemed to fluctuate...

 

[yodanut91]

I might try a tstat if I cant get it running right. Misses slightly at idle.

 

[JacksSmirkingRevenge]

Did you ever figure this out? Sub'd.

 

[M32H32is]

i was fighting a high idle problem and replaced the coolant temp sensor. The idle came down and get close to 2mpg better milage. But i didn't start out at 6mpg.

Same experience as above, also smoothed out a rough idle.

 

[LS1FJ40]

I'm swapping out my O2 sensors tomorrow. Weather has warmed up but still have crappy winter mix gas so I may get overinflated results. I took my truck to the muffler shop to get a quote for replacing my exhaust from the headers back (including cat) and they said my exhaust was "excellent". No rust. Flow tested my cat from the #2 O2 sensor port and said it was perfect (after 23 years no less). Not only took them a few minutes to check this because my #2 O2 sensor was just dangling there. So I had that exhaust leak and another one at the down pipe.

I will post my results but I will also be doing my plugs, wires, distributor cap, PCV valve this weekend. And EGR delete if I have time. Hoping to get to 12mpg. I drive like a grandma so I'm thinking this is doable.

Tsat is new and functioning. Fan is "roaring" at start up and then running like normal how @jonheld said it should.

Oh, and thinking the charcoal canister replacement is about 10 years overdue as well as I'm getting some hissing from my gas tank when I refuel. So I'll be picking up the VC120 from AutoZone when it comes in tomorrow.

 

[Josie'sLandCruiser]

Hi all,

Stock FJ80 tires are roughly 30 inch diameter. Your vehicle's transmission ratios, axle gears, and ECM programing was set-up for those 30 inch tires. You have also added extra weight (bull bar, etc.) and wind resistance (lift kit, taller tires) to the vehicle.

IMO, re-gearing your axle gears to 4.56 would help put the rig back into the power band of the 3F-E engine.

Regards,

Alan

Hello, having a issue with my rig, it is using ALOT of fuel. I was expecting 11-13mpg with 33's. But I got 6mpg. Constantly.
Specs are
33x12.5r15 tires
4" lift
arb bull bar

No engine light or rough running.

I have done
new spark plugs
new plug wires
new cap and rotor
new air filter
egr and smog delete
valve adjustment
Seized caliper(replaced)
new oil in everything
re built a440f trans with new torque converter.

What do I do next!? It has a little power but nothing above or below average. I am running 87 octane in the tank. I have run 3 cans of injector cleaner though it over the past 5 months. Could the cat converters be pooched? I have a lot of suit on the tail pipe too. Could leaning out the afm help? I don't know much about the 3fe so what advice you have is helpful

A lot of people have made threads on bad mileage but they are getting 8-9mpg, mine is at 6 and the engine seems to run great with no stumble or hickup.

HELP ME! I am spending a fortune on gas! A tank only lasts 200km/120mi!!!!!!!!!!!!! I am not hard on it either I cruze at 100km/h -60mph no hard starts or hard acceleration.

 

[LS1FJ40]

Hi all,

Stock FJ80 tires are roughly 30 inch diameter. Your vehicle's transmission ratios, axle gears, and ECM programing was set-up for those 30 inch tires. You have also added extra weight (bull bar, etc.) and wind resistance (lift kit, taller tires) to the vehicle.

IMO, re-gearing your axle gears to 4.56 would help put the rig back into the power band of the 3F-E engine.

Regards,

Alan

I run 31x10.50 BFG AT KOs and the only mod I have is a TJM aluminum bumper that weighs less than the stock bumper. And I've removed the third row seats. My truck is actually weighing less than when I bought it 23 years ago new. It isn't the tires or weight. It's the 234k miles and maintenance/tune up needed.

 

[yodanut91]

I never figured it out. Got pissed off and sold the hunk of crap. Kept randomly not starting and had a lot of body damage.

 

[Aggiesdm]

I run 31x10.50 BFG AT KOs and the only mod I have is a TJM aluminum bumper that weighs less than the stock bumper. And I've removed the third row seats. My truck is actually weighing less than when I bought it 23 years ago new. It isn't the tires or weight. It's the 234k miles and maintenance/tune up needed.

Any updates on the 3FE performance? I'm getting 8-9 MpG and trying to figure out why. I used to get 10-12 pretty regularly with same setup. All maintenance is up to date. Curious about temp sensor. I haven't replaced that.

 

[LS1FJ40]

Any updates on the 3FE performance? I'm getting 8-9 MpG and trying to figure out why. I used to get 10-12 pretty regularly with same setup. All maintenance is up to date. Curious about temp sensor. I haven't replaced that.

I've replaced the temp sender and O2 sensors. I honestly didn't think changing the O2 sensors would be a big deal. However, I just ran my second tank of winter mix 89 (with 10% ethanol) through it since changing the O2 sensors. 9.7 mpg, up from 5-6. I had exhaust leaks from the second O2 sensor just hanging loose and from where the down pipes met the exhaust.

I haven't had time to change the cap, plugs, wires, and PCV, or do my EGR delete yet. I suspect that those will add minor gains as well. Hope I get back to the 12-14 mpg range.

My 9.7 mpg was with 75-80% city driving and 20-25% highway. Stock 92 FJ80, 3FE, 234k miles.

 

[Eicca]

Don't settle for less than 13.

 

[Alleycats]

I'm getting 11.5 city and 14 highway running 32" tires, maybe try retarding your timing and see if your mpg's increase?

 

[LS1FJ40]

I think timing is definitely an issue on my 92. I just haven't had (or taken is probably more accurate) the time to mess with the timing or do the other tune up stuff.

I've owned my 80 since new in 1992. I used to get 13-14 mpg. I know it's doable. Just needs a little TLC to get back there. My plugs and wires are probably 7-8 years old. At least. Cap is 6 years old. She's burning rich.

 

[Alleycats]

So maybe if your plugs are on the black end of the spectrum try advancing the timing, forget the timing light just loosen the 12mm bolt at the base of the distr. and to advance turn counterclockwise, just mark where it is now so you can return to that if you need to, and tighten the 12mm. Oh and I guess your supposed to put the jumper thingy in.

My .02

 

[LS1FJ40]

Yeah, I don't know what I'm at right now but the 3FE is supposed to be at 7 degrees.

 

[Alleycats]

I'm saying 'play' with it and see if it helps.

 

[LS1FJ40]

Agreed. Is the jumper wire necessary?

 

[White Stripe]

I believe some of the 3fe era motors from toyota had distributor problems and don't advance correctly when they go bad.. I would swap in another distributor and see what happens. Those EFI systems of that era could have a host of problems without throwing a check engine light. Plugged cat is a possibility, pull the o2 out and drive it, if you have more power than the cat is plugged. Anyway I would start with the distributor in my opinion and go from their.

 

[LS1FJ40]

Cat is free flowing. Had it pressure tested when I replaced the O2 sensors. It is "perfect" according to my muffler shop. I suspect that is because the 2nd O2 sensor was just hanging and I've been burning rich so she's nice and clean. I was prepared to cut it out and eliminate it but he tested it three times and it's clean as a whistle.

 

[White Stripe]

Cat is free flowing. Had it pressure tested when I replaced the O2 sensors. It is "perfect" according to my muffler shop. I suspect that is because the 2nd O2 sensor was just hanging and I've been burning rich so she's nice and clean. I was prepared to cut it out and eliminate it but he tested it three times and it's clean as a whistle.

I was addressing aggiesdm's question since usually a plugged cat causes a significant loss in MPG. Sorry for the confusion. As far as your situation LS1fj40, a couple things come to mind, I would check the FPR. If fuel pressure is too high it could cause a rich scenario. AFM could also cause it. Also check vacuum lines for leaks and tears which can throw things off, might be good to replace all your vacuum hoses-cheap and easy. And the distributor could also be an issue as mentioned in my last post in this scenario as well I think. Hope this gives u some ideas. I have no idea how you would test the distributor for proper advance to confirm your old one is working properly. Some of the older knock sensors had issues as well if your motor has one. Im more experienced with the 3vz-e and 3vz-fe but they have similar efi as the 3fe I think.