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Here's a couple pics of my T. The one with all the ice is from a trip driving through the mountains in Tennessee in the middle of a snow storm, the roads were crazy had to have seen 20 wrecks on the side of the road, I was in 4H the whole time.
Is your 3.4L truck 4x4? The 2wd tricks generally came with higher geared axles compared to the 4x4 models. Like my 86 2wd has 3.56 gearing, while all the 86 4x4 trucks I've had were all 4.10. My T100 has 4.10 gearing, my dad's has 3.91, the rest are 4.10, but never owned a 2wd yet. If I drive my extended cab 4x4 with 3.4L easy for a longer trip I can easily get 20mpg, probably can get 22-25mpg in warmer weather. I have 32in tires on it, so slightly over sized from the stock 31in. MPG calced based on odometer, so the distance is off about 2.5% and actually gets slightly better since 32in tire goes farther per turn than a 31in. Only accounts for + 0.5 better mpg so hardly worth mentioning though. My Tacoma standard cab 4x4 3.4L had a hard time getting 20mpg, that was about the best I could get out of it. Not sure what's different, both were R150F transmissions, both sticks, both 4.10 gearing and the Tacoma is lighter, but the T100 does do just as good or slightly better.
I've had a guy tell me he got 27mpg with their 2.7L 2wd long box T100 on the expressway. Not bad for driving it "normal"
@t100
NC trucks are so clean, that's where my dad's T100 came from, rust free basically except where the rear bumper and frame meet was a bit rusty. Makes working on them so much easier too.
Getting around 30mpg with a 4x4 3.4L with 4.70 gear ratio just doesn't add up. What's your rpm going 55mph?
I can be a pretty extreme hyper-miler, my corolla is rated 23 city 31 highway, but I've gotten it up to 44mpg on a tank average and a whole summer averaged over 40mpg. I drove 45mph though, worked midnight so no traffic so lots of coasting and I had a scanguage 2 to monitor loads, mpg etc constantly while driving. Driving without really thinking about it I'm pulling around 37mpg out of it. Only way I see 30mpg from a T100 without it being highly modified is to have a efficient diesel in it. Just for context, the 98 T100 4x4 3.4L is rated for 15mpg city 18 highway with a manual. If I drive my T100 around 45mph I can hit about 28mpg instant while moving but that doesn't account for stopping or take offs where most mpg is lost.
Also something to note, the axle code table isn't accurate for the T100, it's a special case machine. If I remember right the middle 2 numbers being 03 is 4.10 and 02 was 3.91. I think 2wd ones had 01 as the code, but don't know the ratio. 04+ I've never seen on a T100, only Tacoma/4Runner for 4.55 and such. It's been a long time since I searched it, so my codes are probably off a little.
Do you have anything done to your truck that's special or aftermarket? Also how did you calc the MPG, just go about a 1/2 tank and fill up and calc from there or what?
Ahh ok, so it's more guessing. The way to accurately get mpg figures is to fill the tank to some standard (first click, or fill slowly to it kicks off etc) and that's your "reset" point. Reset the trip and drive, further down you drain the tank the more accurate it will be. Once you get to say 1/4 tank or less, fill up using the same process again, and preference is to use the same pump. When it's done it gives you the total fuel used. Take the miles you traveled, add % differences for gear ratio/tire size difference from stock, and then divide by the gallons used.
Also to note, the rim size makes no difference at all on mpg besides a weight factor, it's the tire height that determines how far you travel in one tire turn. I personally run 16in on all my 4x4's, but that is just because the tires are cheaper because it's very common on dually trucks and they run a tall skinny tire.
Generally with my experience, you loose a lot of torque when you have no exhaust but maybe gain a tiny bit of hp at the top of the rpm range. MPG is more or less torque at lower rpm (cruising speed) so if anything that's hurting MPG. With a turbo that wouldn't matter, super charger on the other hand I'm not sure how it effects it.
Also careful on the wheel spacers, I'd personally suggest steel ones if possible. The AL based ones you'll want to check the torque on after 25-50 miles. That means you have to take the tire off to check the hub torque, then reinstall the wheel. If you drive it on the road a lot, I'd check again in another 50-100 miles. Having a tire come off is no fun.
Also on the PVC valve, I'd suggest atleast a filter on the hose so you don't get dust and such into your engine.
I'd still be interested in seeing some documentation about more engine grounds making more power/mpg if you happen to know of any write ups online.
You don't happen to have ethanol free fuel over there do you? I could see that accounting for 5-10% difference in mpg. Maybe you have a lot of carbon build up in your engine boosting compression ratio and somehow getting benefits from it. Higher compression = higher mechanical efficiency atleast to a point.
First result on the big 3 grounds related to sound systems with a dedicated amp and high output alternator which makes sense since it's drawing high loads though wire designed for the OEM alternator. I'll have to look around a bit more and see what else is said. If you want to post up pics, post them up, I'm sure other's wouldn't mind seeing them too. Also do you have a high draw sound system too, or stock radio (or similar) radio?
For tire size you mentioned you went to 17in tires, the rim size doesn't dictate the rubber tire size unless you stick with the same numerical tire size and went to a larger rim. I like to convert the height to inches since it makes the most sense.
I've had good luck with seafoam too, it seems to clean pretty well for fairly light carbon. Heavy scaling of carbon it has a harder time with, but treating it multi-able times it does remove quite a lot of it. Another product that is less known is System 48 which is an oil treatment. It leaves a buildup on all friction points. I can't say it always works, but I've seen it make cars smoke less or cure smoking from bad rings or valve stem seals, and if the engine somehow gets drained of oil, the engine lasts a bit longer since it has the layer built up on it that still lubricates. No oil pressure is still a bad thing and tears stuff up, so it's not a cure all.
I have a friend that bought a 4runner with the 3.0L engine with 400k miles and ended up with around 680k miles before he scrapped it because the back end was getting rusty (his nickname is Mr Clean if that hints to anything). He had a friend buy one that had the same sticker options, color, year etc and his lasted around 650k. Both had head gaskets replaced around 300k. I have a 2wd pickup with the same engine and it has 512k miles and still runs fine, but I can tell it's low on compression. The 3.4L is basically a later version of the 3.0L.
NC trucks are so clean, that's where my dad's T100 came from, rust free basically except where the rear bumper and frame meet was a bit rusty. Makes working on them so much easier too.
I wish it was an NC truck. The truck came from Maryland. I've got plenty of rust on the underside. Right now I've got the rear axle housing removed because of pin hole leaks from rust. I cut out the bad section and I fabbed up a new section to weld in.
As for mileage I've never gotten more than 18mpg. I usually average 15mpg, but mostly drive it around town, and I drive it hard. That's with 265/75/16's that measure about 31.5" and basing my mileage off of the odometer with no correction for the larger diameter tires.
Yea the 15-18mpg is pretty typical for town/city driving, I'm 25+ mins from the nearest town so all of my trips gets the engine fully warmed up and such, kind of ideal for mpg numbers even though I have to travel much further on average. I've never seen a Toyota axle rust enough to leak and I've picked up an 86 pickup that literately was sitting in the ground about 6 inches or so with no tires. I was shocked the rear drums broke free so easy when I dollyed it home. The guy had to take his fork truck to pull it out of the frozen ground for me to put tires on it lol. Also a note, the T100 had two stock tire sizes based on the options it came with and maybe year as well. My dad's had the tiny like 28in tires stock even though it's 4x4, but it had 3.91 gearing. My 98 came with 31's and 4.10 gearing. The speedometer would probably be the best way to tell which tire size was stock. 31in to 31.5in is like 0.25mpg difference if you got 20mpg. Going off memory, my truck runs around 3k rpm for 70mph, I catch myself trying to shift into 6th every once in a while, but I keep lower rpm and the 3.4L loves around 2000-2500rpm for mpg while still having fairly good response/power. It's pretty flat around my area so no major hills to deal with too. My corolla on the other hand is around 1700rpm for 55mph based on the OBD2 scanner (no rpm gauge), never checked 70mph, it kicks down to 3rd gear on any hill of fair size.
@Tilikum102602
Just to note, the 3.4L engine was only installed in 95+ T100s. The engine code 5vz decodes to the 5th version of the VZ block, the 3.0L is a 3vz. Same story for the 22r/re, there's 20r, 18r, 16r etc. Heads/intake were a major change from the 3.0 to 3.4L, but the bottom end is nearly identical, the crank and crank bearing assembly I know are the same part numbers which tells me the stroke is the same on both engines, just the 3.4L was bored larger. I've read the 3.4L heads bolt up to the 3.0L block, but haven't found any posts of anyone actually posting what kind of results. I guess there's some cooling passages that don't line up right or something so probably not something simple to make work.
If you want to talk about the 2JZ motor, you can't forget about the 1UZ v8 engine from the lexus LS400 and GS400. From what I've poked around about them, the engine was designed by the same team as the Supra engine. Haven't had any experience with the 2JZ or 1JZ, but the 1UZ is a super smooth running v8 and handles a ton of boost and abuse very similar to the 2JZ engine. If I remember correctly the 3.4L wasn't initially designed for the super charger, don't remember the details off hand, but I think a 97 or 98 ECU was required because the older ECU couldn't handle the difference. Also the 7th injector is a very common "upgrade" since the 3.4L with supercharger tends to run lean when running it hard and the 7th injector is used to off set that. I guess another option I never see mentioned could be replace the 6 injectors with larger injectors, but I guess the 7th injector kit is cheaper to do, to be the popular choice.
That engine's clean! Looks so much easier to work on without all the vacuum line's running everywhere.
I have a 97 Xcab with the 3.4 and 4x4. Just hitting the one year mark with it and finally at the point where it's on the road more than its sitting in my driveway. It's my dd so I want to keep everything simple with it. I do mainly city driving and i kind of want something smaller, rav4, crv, 4runner, but until I have the budget, it's me and the T.
I just got it highway safe recently rebuilding most of the front end. ball joints, tie rods, replacing the grease in the cv boots, cleaning and regreasing the bearings. and new kyb gas ajust shocks all around (i really like these, great for living in a city full of potholes). So I've taken it out on the highway a couple times, doing about an hour drive from louisiana to mississippi and it feels good. there's still a little bit of a wobble. I'm going to go back and retighten one of the bearings that I was lazy on and see if that won't keep it straighter down the road. But I got it up to 65, maybe 70, i dont remember. So Im happy.
But I'm taking it on a long trip this summer and I got a lot of work to do on it before then. Timing belt and water pump. Replacing a bunch of fluids, testing out the 4x4. get my throttle valve to stop sticking so my idle will get back to normal. City driving has been making the idle higher and higher. but i can tap the gas pedal and it will drop back to normal. I'm gonna try this washer trick I've been reading about on this forum and see what happens.
Other than that, I've got a oil leak on the passenger side that should be addressed and my rear brakes are rusty. I guess this truck spent a bunch of years on the gulf coast and had plenty of surface rust on everything when i got it. I spent a couple days with a wire brush cleaning clay off the underside of everything when I first got it and everything's pretty clean at this point.
And my a/c doesnt work so the dogs are gonna have to stick their heads out the window this summer. I was originally trying to buy a tacoma but I do like the roomy interior of the T. It seems much easier to live out of for a couple weeks than a tacoma. I'm hoping to find a camper shell but from the prices I've seen, I don't think I can do it right now. I'm hoping I can find a cheap toolbox on craigslist to throw expensive gear in. And I'd like to get a farm jack (which I hopefully won't need) and the proper wrench to get the spare rim off.
SO I got a little laundry list to take care of before June/July but nothing seems expensive. I'll probably take it to the dealer for the timing belt so that's the only major expense I can foresee at the moment. But at the moment, it's nothing special. Just a lil work truck and grocery getter.
For the no AC, go grab an AC recharge kit from the parts store for $20-40 (don't worry about getting anything special, just need the hookups etc). Follow the directions on it and likely the AC will work afterwards. Also note, if you start the engine and turn the ac on (ac button in, light on), look @ the ac pump on the engine. If it isn't spinning, it likely has no charge left. It lost it's charge, so it might leak out again over a short time, or take a few years. You could overhaul the AC system and pull all the connection points apart that use O-Rings and replace them with AC safe ones (typically green from my memory).
If your valve cover gasket is leaking, you can get by by snugging up the bolts for the valve cover till you get a chance to do the job. I did that on the two 3.4's I have and it stopped the leak on both for now. The rubber seems to shrink with age and the bolts get loose.
Some day I have to make a trip down south and get me a clean body T100 95% of them up here are rusting out.
Also on the shake/vibration, if it is always there, it's something not spinning true (off centered, crooked etc). If it's only there at higher speeds and gets a lot stronger within about a 10-15mph range, it's a balance issue, likely the tires, maybe a wheel weight fell off or hasn't been balanced? My Lexus LS400 is super smooth, but around 75-80mph on the high way (it's 75 here), I have a tire out of balance. I rarely go that fast, so it doesn't bother me and it's quite minor.
The extended cabs are way more common, but Everytime i see a T100, I try to buy it, And i dont know much about the 2.7 but my 3.4 4 weeks ago from orem utah to idaho falls and back got like between 28-31 mpg. The regular cab is lighter and Their are other things i have done like Gounds, bigger tires, etc
I just bought a 98 T100 SR5 4x4 3.4, 278k on the odo, about a month ago. My first T, for now. My MPG is in the neighborhood of 15-16. It's my dd and I really dig it but I'm in SoCal and gas prices are kicking my ass. Especially when I blow through half a tank every two days.
I don't know how you're able to get that mileage. I'm not leaking, not blowing blue smoke, no hesitation, new plugs. It appears well taken care of by one owner only. Kinda scratching my head especially after what your T is able to do.
12-17-2017, 05:54 AM
