HaYnrunner
New member
stock 2wd
I "fixed" my poor fuel economy
- Thread starter A.Wilson013
- Start date
Granted that's like 75% quick city trips in the winter, still sucks quite a bit. Defroster usually on, might see if I can make it a tank without using it most of the time.Did you see my pm? Lol [emoji1]
IBallEngineer
New member
Sadly I have to jump in the mix here. I have a 2000 3RZ Automatic which came with the little 225's that belong on a go cart. Drove it maybe 15K getting 19-21mpg on average. Yes occasionally got close to 22, but that's not realistic to expect. Switched to 265/70's and the range changed to 17-19, mostly attributable to speedo error, 4-5% would get me a little back but not all the way. Still I can live with it.
THEN a few weeks ago I got 14, FOURTEEN MPG!! I tow a small trailer frequently and although it doesn't weigh very much even with my load of maybe 300Lbs it does bring my average down to the low end of the scale. But 14 is just other worldly type of bad. After 3 tank fulls of this, I filled up Friday with the intent I would look in to this on the weekend. Well my wife and her sister and my son and my step son and my Bro in law and my step daughter's cabinets, and the granddaughter all conspired to eat up my time. So I didn't do squat!
My plan isn't very high tech, I'm going to clean the MAF and replace the spark plugs. I'm also going to try to drive with the scan tool connected and monitor a/f and 02 activity. Fuel trim too if I can get a little more info. Never thought I'd say it but 17 looks pretty good when you get 14-16 out of 4 fill ups. I will do one thing at a time, so I can document the change. MAF cleanout first!
THEN a few weeks ago I got 14, FOURTEEN MPG!! I tow a small trailer frequently and although it doesn't weigh very much even with my load of maybe 300Lbs it does bring my average down to the low end of the scale. But 14 is just other worldly type of bad. After 3 tank fulls of this, I filled up Friday with the intent I would look in to this on the weekend. Well my wife and her sister and my son and my step son and my Bro in law and my step daughter's cabinets, and the granddaughter all conspired to eat up my time. So I didn't do squat!
My plan isn't very high tech, I'm going to clean the MAF and replace the spark plugs. I'm also going to try to drive with the scan tool connected and monitor a/f and 02 activity. Fuel trim too if I can get a little more info. Never thought I'd say it but 17 looks pretty good when you get 14-16 out of 4 fill ups. I will do one thing at a time, so I can document the change. MAF cleanout first!
Jaketino
New member
Last time I drove that trip I got extremely high gas mileage as well. Not trying to burst your bubble or anything. Last weekend I came back from Lincoln City to Vancouver and got 19.8, locked at 60 mph and under 2k RPM. Normally I get close to 15 but I atribute that to my lead foot.
A.Wilson013
New member
Well, since then I have been able to replicate it on every tank =)
Defrost on for a bit to get the windows clear, then off for the rest of the time. Pulling high 16's around town, 18-alllmmmooosstttt 19 on the freeway.
Mines stock with the lowered aero package (aka sagging springs) and I get 23+ mpg cruising at 65mph. With a mix of highway and around town driving, and a very light foot, I can average 20mpg. This is a 2002 sport edition, if that matters.
Not exactly, overdrive is in addition to the four main gears.
Watch your shifts carefully sometime. You'll see 1 - 2 - 3 - 4, and then right at 50mph (unless you're accelerating hard) you'll see rpms drop a tad. That's overdrive. You still hit fourth gear with overdrive off.
Way back when they were first introduced it was manually activated. When you got up to cruising speed you'd engage overdrive, which was a separate gearbox bolted to the transmission. Now it's all electronically controlled, but it's effectively a fifth gear on a four speed transmission.
Not exactly, overdrive is in addition to the four main gears.
Watch your shifts carefully sometime. You'll see 1 - 2 - 3 - 4, and then right at 50mph (unless you're accelerating hard) you'll see rpms drop a tad. That's overdrive. You still hit fourth gear with overdrive off.
Way back when they were first introduced it was manually activated. When you got up to cruising speed you'd engage overdrive, which was a separate gearbox bolted to the transmission. Now it's all electronically controlled, but it's effectively a fifth gear on a four speed transmission.
What you are describing is torque converter lockup, not the transmission shifting into overdrive.
paddlenbike
Member
Alex, I track my fuel economy on every fill-up, and have done-so since 2005. I have been surprised over the years to only loose about 1 MPG going from stock to a 2.5" lift with load range D 265/75R16 tires and a supercharger. For reference, I got 21.5 MPG bone stock. 20.5 MPG after the mods I just mentioned. Last year I moved to 17" Tundra wheels (like you) and 275/70R17 tires and lost 1 more MPG, down to about 19.5 MPG highway now. When you consider that the EPA only rated my vehicle for 19 MPG on the highway, I am feeling pretty lucky to get that with everything I have done to my truck.
So beyond the obvious that larger tires, lifts and a loaded roof rack affect fuel economy, so does use of the A/C and gear choice on long grades. Mine is a manual and I found that going from Sacramento at just over sealevel to Lake Tahoe at 7,000 ft, I get better mileage climbing the grades in 4th gear than I do in 5th. With the supercharger the truck has more than enough power to climb the grades at just about any speed in 5th, but it's pulling 2-3 pounds of boost in 5th (and using a richer fuel mixture), as opposed to pulling the hills in 4th at around 0.5-1 psi and 14.7:1 AFR. I know you're supercharged too, so it's something to think about. (I know you're auto, but try manually changing down a gear and seeing what happens to your AFR and resulting fuel economy.)
In strictly high elevation driving I seem to get slightly better mileage with the supercharger than I did when I was NA and had to push it pretty hard to stay at speed.
So beyond the obvious that larger tires, lifts and a loaded roof rack affect fuel economy, so does use of the A/C and gear choice on long grades. Mine is a manual and I found that going from Sacramento at just over sealevel to Lake Tahoe at 7,000 ft, I get better mileage climbing the grades in 4th gear than I do in 5th. With the supercharger the truck has more than enough power to climb the grades at just about any speed in 5th, but it's pulling 2-3 pounds of boost in 5th (and using a richer fuel mixture), as opposed to pulling the hills in 4th at around 0.5-1 psi and 14.7:1 AFR. I know you're supercharged too, so it's something to think about. (I know you're auto, but try manually changing down a gear and seeing what happens to your AFR and resulting fuel economy.)
In strictly high elevation driving I seem to get slightly better mileage with the supercharger than I did when I was NA and had to push it pretty hard to stay at speed.
AntleredRuin
New member
Max I've gotten is 21.8. Cruise control at the speed limit ALWAYS and never went faster than 60, never saw over 2k RPMS.
This was mostly freeway. When more mixed with city, I average around 18.5.
Accelerate like a grandma, and your MPGS will go way up.
This was mostly freeway. When more mixed with city, I average around 18.5.
Accelerate like a grandma, and your MPGS will go way up.
diverscale
Member
Just to add to the above post by [MENTION=134872]The Count[/MENTION], and to disable spreading of misinformation:
You are describing the converter lock-up, which is a totally different system than the ''overdrive''. For example, on the 5th gen, you have converter lock up on 3rd, 4th and 5th gear. But only the 5th gear is overdrive.
On our truck, 4th gear is overdrive, and is the only available for converter lock-up.
Overdrive is simply a term for a gear ratio higher than would be a direct-drive by the engine.
MyHigh
New member
Hmm....
I would have thought you'd get better mileage heading down to Seaside rather then heading back home, I mean it's all up hill.:wow:
On my recent trip to SD I noticed via scan gauge that I'd hit 19-20mpg at 68 and drop off to 17-18 at 71 both on cruise control. Another thing I noticed was how easy my truck would cruise at 80mph while down their when it struggles back home in Portland, I'm pretty sure it's a mind game but I swear driving on SoCal concrete highways is way easier then our asphalt roads.
I would have thought you'd get better mileage heading down to Seaside rather then heading back home, I mean it's all up hill.:wow:
On my recent trip to SD I noticed via scan gauge that I'd hit 19-20mpg at 68 and drop off to 17-18 at 71 both on cruise control. Another thing I noticed was how easy my truck would cruise at 80mph while down their when it struggles back home in Portland, I'm pretty sure it's a mind game but I swear driving on SoCal concrete highways is way easier then our asphalt roads.
IBallEngineer
New member
I'm afraid that's not correct. Overdrive does NOT come on if it's off, and it is 4th gear on a 3rd gen. No 5th gear on our rigs.
:gossip:
Ok, I apologize for getting it wrong.
I didn't know the term overdrive had evolved to simply mean your top gear. On every transmission I've worked on there was an actual overdrive unit, bolted to the tranny, that when engaged changed the effective gear ratio between the transmission and the wheels. Granted, the transmissions I'm talking about were rather old, part of my dad's classic car hobby. But that is what the term overdrive originally referred to.
In that case I might disable overdrive for off roading, but why bother for towing? I suppose if the tranny was constantly bouncing between 3rd and 4th, but if it will happily cruise at 60mph or whatever in 4th then I say let it.
KatRider05
New member
There is torque lock in 3rd gear as well.
IBallEngineer
New member
It isn't simply "top" gear. It is just like the one's on your dad's hobby cars except it is built in to the transmission. And Overdrive means it's an "overdriven" gear, over as in past 1:1 which was traditionally top gear. Usually around .70 to .78 or so. This mean the engine is turning slower than the drive shaft. Allowing higher vehicle speed without as high of an engine speed.
Towing requires more power, and the slower engine speed often is not suited for that, especially our anemic 3RZ. Thus turning off overdrive keeps the driveability halfway normal if the towed load is big.
D Farms
New member
A while back I read through clownmeats thread and he said that while looking at the wiring for the automatic transmission he found that he could lock up the torque convertor electronically. Is that even possible? I was under the assumption that the torque convertor locked up by itself at a certain rpm if there wasnt too much torque going through it. id love to be able to lock the torque convertor around town, with my tires and gearing it wont lock until i get up to about 51 mph.
