3vze bad gas mileage

[RonJR]

Check the gearing first. A lot of 2nd gen 3.0 5-spd 4runners were set up for 31 inch tires at the factory. If so, it will have 4.56 gears. Ignore the door sticker that shows a smaller tire. Toyota shipped the vehicles to the U.S. with the smaller tires to avoid some import duties, then had the dealers put on the correct 31's. I think G254 is the door code for 4.56 gears.

I think the autos had 4.30 gears for the 31 inch tires, but not sure.

 

[T4rmtber]

Door says g114. Which I believe is already 4.88. I just got the truck I guess it just guzzles gas around town.

 

[WPG93]

I'm having a similar experience, only getting about 10mpg in the city. It's not crazy stop and go though, usually fairly smooth. I do have a small lift and A/T tires though. I plan to pull my distributor plugs to be sure all my cylinders are firing and I don't have a stuck injector, and also leaning out the AFM. Exhaust smells pretty bad. No symptoms of head gasket issues.

I was wondering if anyone has an automatic 3VZE like me who would share what their rpms are at different speeds so I can get an idea of mine is working harder than it is supposed to. Just set it on cruise control at different speeds and note the tachometer for me please! I'll do the same since the numbers I know are in KMs

 

[FISH HUNTER]

I'm having a similar experience, only getting about 10mpg in the city. It's not crazy stop and go though, usually fairly smooth. I do have a small lift and A/T tires though. I plan to pull my distributor plugs to be sure all my cylinders are firing and I don't have a stuck injector, and also leaning out the AFM. Exhaust smells pretty bad. No symptoms of head gasket issues.

I was wondering if anyone has an automatic 3VZE like me who would share what their rpms are at different speeds so I can get an idea of mine is working harder than it is supposed to. Just set it on cruise control at different speeds and note the tachometer for me please! I'll do the same since the numbers I know are in KMs

I have a 93 3.0. running 31x10.5r15 on Open Country Yoks.

I used to get about 10-13 MPG, now I get about 16-17 on all highways and about 13-14 combo. I get about 230 (average) and 250 miles (on a good day) on a tank of gas.

Over the last 10 years, I have had the following issues corrected on my truck

The Shifter Solenoids were bad, had them changed out

The previous owner used an after market T belt that that thew off the timing a bit. I guess some after market belts, use one belt for different applications, so the distance of the treads on the t belt are acceptable but not to OEM standards.

Make sure you OD is kicking in.

I installed a manual locking hub (so the front axles are in free and not locked all the time)

Installed the 4 hole Flame Thrower injectors and that worked for a short time, but Im back to stock ones now.

I chipped my ECU, but now Im back to running a regular ECU.

I recently ran the Lucus Upper Cylinder gas treatment, and surprisingly that also helped my MPG. I no longer have a regular drive routine so its harder for me to gauge my average MPG.

My RPM at 70MPH is about 3K RPM.

 

[WPG93]

Cheers for the response Fishhunter, I like the idea of manual locking hubs. Also should look into timing, but it does start very well.

Couple updates though, and not great ones for me. I calculated my mpg on my last fill up and I was getting an amazing 8.6 mpg haha. It seems crazy to me that I can get this low of economy without crazy noticeable performance issues. Probably if I drove one of your 4runners I would realize the difference. It is pretty slow to accelerate, I had written that off as people said the 3VZE lacked guts but maybe mine lacks more. The truck sounds a bit like a diesel when it's idling. It sounds pretty good under the hood I think but the exhaust has a bit of a blub blub to it. Can an exhaust issue cause this kind of fuel economy? I've also noticed, as many of you have too, that my tank builds up more pressure than any other vehicle I've owned. Not sure if pressure in the tank can cause bad fuel economy though? My tires are only 235/75/R15 BF KOs so they're not huge, and while my truck is lifted I'm only driving city speeds of max 45mph so I doubt the difference in drag is very much at all.

 

[RonJR]

I would suggest doing a compression test. You may have a burned valve. This is particularly possible if there is no record of the valves ever having been adjusted. Your "blub-blub" exhaust is suspicious in that regard as well.

 

[WPG93]

Sounds like you're onto something Ron... In the case of a burnt valve does that piston still fire? I planned to do a compression test just to extra rule out the head gasket but now you're making me nervous...

 

[RonJR]

Sounds like you're onto something Ron... In the case of a burnt valve does that piston still fire? I planned to do a compression test just to extra rule out the head gasket but now you're making me nervous...

Depends on how low the compression is. If the leak is bad it won't fire, but there's a range where it just performs poorly.

The 3vze doesn't have misfire detection - that didn't come about until the 1996 models with OBDII diagnostics - so you wouldn't necessarily throw a code.

On a 3vze, the valve lifter clearance continues to decrease as the valve wears into the seat. When the clearance gets to zero, the valve stops closing all the way, and at that point it starts burning rapidly as the hot exhaust gases blow by it.

 

[WPG93]

Thanks Ron, appreciate it a lot. The longer I have this truck the more it is a project. There's a 3VZE on the market here for 400 bucks with 190 miles on it and rebuilt seals, wondering if I should pick it up if the compression test fails.

Also along the lines of fuel economy I've never seen this truck idle below 1000rpm. What's the normal idle for the 3VZE?

 

[FISH HUNTER]

Cheers for the response Fishhunter, I like the idea of manual locking hubs. Also should look into timing, but it does start very well.

Couple updates though, and not great ones for me. I calculated my mpg on my last fill up and I was getting an amazing 8.6 mpg haha. It seems crazy to me that I can get this low of economy without crazy noticeable performance issues. Probably if I drove one of your 4runners I would realize the difference. It is pretty slow to accelerate, I had written that off as people said the 3VZE lacked guts but maybe mine lacks more. The truck sounds a bit like a diesel when it's idling. It sounds pretty good under the hood I think but the exhaust has a bit of a blub blub to it. Can an exhaust issue cause this kind of fuel economy? I've also noticed, as many of you have too, that my tank builds up more pressure than any other vehicle I've owned. Not sure if pressure in the tank can cause bad fuel economy though? My tires are only 235/75/R15 BF KOs so they're not huge, and while my truck is lifted I'm only driving city speeds of max 45mph so I doubt the difference in drag is very much at all.

You might have more than one issue. Make sure the timing is right. Check you TDC too.

For the compression, if its low, then pour some oil down the cylinder and take another reading. If the compression goes up, then your rings are bad, if the compression does not go up, then the valve (s) might be burnt.

Your exhaust is just sending sounds from our engine. So its probably not the exhaust.

Is your radiator fluid going down after a period of driving?

Can you smell any radiator fluid smell in your exhaust (don't breath your exhaust for a long time)?

Is your cat plugged up?

When you start your engine, do all the idiots light (the CEL) light come on for a short period of time? If not, you might have a CEL light but not know it.

 

[FISH HUNTER]

Thanks Ron, appreciate it a lot. The longer I have this truck the more it is a project. There's a 3VZE on the market here for 400 bucks with 190 miles on it and rebuilt seals, wondering if I should pick it up if the compression test fails.

Also along the lines of fuel economy I've never seen this truck idle below 1000rpm. What's the normal idle for the 3VZE?

On your idle, the idle screw is on the throttle body. There is a flat head screw facing the front of the engine. The more you turn the screw in, the lower our engine idle will go. Your idle should be around 600-750 RPM. Again, check your timing and also TDC

 

[WPG93]

Fish Hunter, you are the man. Let me fill you in on some of these details.

You might have more than one issue. Make sure the timing is right. Check you TDC too.

Timing is one way I am leaning as well. I just didn't think it would start this well if the timing were off. Even at cold temps without the block heater it always starts around the 3rd crank. I'm guessing by TDC you mean top dead center. I assume there are markings on the pulleys to do this right? Or is it important to check that the engine is actually at TDC when that bottom pulley is lined up with the markings?

For the compression, if its low, then pour some oil down the cylinder and take another reading. If the compression goes up, then your rings are bad, if the compression does not go up, then the valve (s) might be burnt.

I have heard this, just having trouble getting ahold of a compression gauge with my work schedule. Hoping to get some of this done this weekend!

Your exhaust is just sending sounds from our engine. So its probably not the exhaust.

The reason I'm wary of the exhaust is that it was changed by one of the two previous owners, so not sure if it was done to OEM standards.

Is your radiator fluid going down after a period of driving?

Can you smell any radiator fluid smell in your exhaust (don't breath your exhaust for a long time)?

I haven't experienced any of the tell-tale head gasket signs I've seen around, but I'm not completely counting it out. Underneath the oil cap is completely clean and bone dry. The coolant level is stable and a bright green. The exhaust smells odd but more like fuel than the sweetness of coolant, also the smoke goes down once it warms up to normal winter levels. The temperature gauge goes up to the middle after 5-10 minutes and doesn't budge after that.

Is your cat plugged up?

I need to look at the exhaust they put in there. I wouldn't be surprised if it doesn't even have a cat. Would the lack of back pressure from not having a cat affect fuel economy?

When you start your engine, do all the idiots light (the CEL) light come on for a short period of time? If not, you might have a CEL light but not know it.

Yeah all the lights come on, the Rear ABS light goes off after a moment or two.

On your idle, the idle screw is on the throttle body. There is a flat head screw facing the front of the engine. The more you turn the screw in, the lower our engine idle will go. Your idle should be around 600-750 RPM. Again, check your timing and also TDC

Is there a fast idle control on this vehicle? Is it never idling lower than 1000 potentially because it's below freezing out? It seems to start at around 1500 rpm and settle down to 1000 rpm once it has warmed up. But I've also read that people find their trucks idle at 1000 for the winter even after they've warmed up but go down to 750 or 800 once summer hits.

Appreciate all the help. Gonna get some wrenches turning soon so that I can start ruling things out.

Paul

 

[FISH HUNTER]

Fish Hunter, you are the man. Let me fill you in on some of these details.

Is there a fast idle control on this vehicle? Is it never idling lower than 1000 potentially because it's below freezing out? It seems to start at around 1500 rpm and settle down to 1000 rpm once it has warmed up. But I've also read that people find their trucks idle at 1000 for the winter even after they've warmed up but go down to 750 or 800 once summer hits.

Appreciate all the help. Gonna get some wrenches turning soon so that I can start ruling things out.

Paul

Have you checked your Air Idle Control Valve (or Idle Air Control Valve)?

Sometimes they get plugged up and you have to clean it with something like gum out.

Top Dead Center.
Take off the Dist Cap and when the rotor is firing on the #1 cylinder, check the pulley to the timing marks....SB TDC

 

[Th3B3an]

Aaahh my 91 5spd 3.0 (loaded with all my work tools, roughly 400lbs) got 16-18city. Sitting on 31x10.5x15 with the stock steel rims. Never could get better than 20highway though.

 

[ctbtiger]

I have a 95 4Runner V-6 4WD with a 5-speed and 31x10.5's and regularly get ~300 miles per tank, which I equate to about 20 mpg. Doesn't seem to vary whether I'm driving city, highway, etc. I'm sure that isn't exact since I normally just divide the # of miles on my tripometer by the # of gallons I put back in the tank. I don't drive too aggressively, but not like a grandma either. Not sure if this is helpful or not, but just thought I'd add another reference.

 

[Jimmy Two Dogs]

Hey guys I know the 3vze gets bad gas mileage but I am only getting 175 miles per tank.

Well, I have a 1990 4Runner with the 3.0 V6. 17-gallon tank. 5-speed. If I fill up, I can drive from here to the beach...210 miles...and still have a tad over 1/4 tank left. That's running 33x12.50-15 Dick Cepeks.

I don't really check the mileage any more, but that's about the same as I was getting when the truck was brand new. I'm not complaining.

 

[oneowner1994]

Bought my 94 4runner V6 automatic with factory 31x10.5 Good Year Wranglers brand new in January 95. Drove it for normal city use and business related road trips, so had the chance to monitor mileage (divide odometer miles by gallons to fill) in real world use. On the highway, I was getting 19 to nearly 20, 16 to 17 around town. However, that was when I ran premium. When I ran regular gas, mileage dropped about 2 mpg or 10%. The factory sticker posted 16 mpg highway and noted that EPA reported mileage was as high as 19 and as low as 13 on the highway. Octane appears to make a 10% difference. For its generation, the 4runner compared very well to other SUVs.

 

[dirteelast]

1992 4runner with 3.slow

im lucky if I get 8mpg! I know my engine is running rich (still not sure how to fix that) and im rolling with 33x12.5 tires which previously stated by others, kills your gas mileage. I still cant help but think there is no way im only getting an average of 6-7mpg.