3vzfe bad fuel economy

[ivan300]

Hey guys i just bought a camry with the 3vzfe engine. It has 136k miles on the odo. On my first fillup i got 13MPG haha and i babied it. The car drives and idles fine. The check engine light is not on. The car does feel a little underpowered though.

So im wondering what are some of the commong things that go bad that i should replace?

I ordered the full engine gasket kit, so im gonna replace the valve cover gaskets. Oil filter housing gasket and anything else thats leaking.

I will also change the plugs, and check the wires and distributor tomorrow. Also check for any vacum leaks.

What else should i replace and clean that will affect my fuel economy.

[Bdub215]

as i advocate for all 3vz owners: advance timing and lean AFM mixture. if your only getting 13mpg something is wrong maybe a bad patch of gas.

[whip_cracker]

Hmmm...

Fuel system cleaner, injector cleaner, change spark plugs, replace fuel filter, run better fuel...

Yeah, that'll fkin change it hehe

[EEngineer]

clogged cat and old O2 sensors

trust me, this is ur problem

[n3rdifed]

Originally Posted by Bdub215

as i advocate for all 3vz owners: advance timing and lean AFM mixture.

could you direct me to how i can do this? and are there unbenefical effects or risks of doing it?

clogged cat...never thought about that

[ivan300]

Hey guys so this is what i did so far

- New Fuel filter
- Spark plugs
- Rotor/Cap
- set timing to 17
- leaned out the afm 3 clicks
- New o2 sensors


I am still getting 13mpg. Though i am driving 90% city but i have been babying it. It should be getting at least 17+

Im tempted to pull out the cat and gut it.

Any other ideas?

[EEngineer]

yea do that..cat can be very problematic

also, try seafoam and clean ur EGR?

and pop ur vavle cover and check for sludge

[mazdaverx7]

let me ask what grasde of fuel you are running. the 3VZ requires premium fuel. do you have a manual or auto trans? are you calculating mileage as a combined city/highway on a full fillup? with my 92 SE with the 3VZ and a 5spd i see around 18mpg in the city and 24+ on the highway if i'm conservative. you may also want to inspect your air filter. a clogged air filter, improperly inflated tires, clogged fuel injectors, and improper plug gap/type can effect fuel economy.

[ivan300]

Originally Posted by mazdaverx7

let me ask what grasde of fuel you are running. the 3VZ requires premium fuel. do you have a manual or auto trans? are you calculating mileage as a combined city/highway on a full fillup? with my 92 SE with the 3VZ and a 5spd i see around 18mpg in the city and 24+ on the highway if i'm conservative. you may also want to inspect your air filter. a clogged air filter, improperly inflated tires, clogged fuel injectors, and improper plug gap/type can effect fuel economy.

I am running 87 octane as per the manual

I have a auto tranny

The calculated 13mpg is combined with mostly city

The air filter is clean just checked it

I just checked the tires, 2 were 30 and 2 were 26. I inflated them all to 35

The fuel injectors could be clogged. I ran some cleaner in the tank but i doubt that does anything

The spark plus i installed were pre gapped platinum tipped plugs.I was getting the same mpg before i changed the plugs

[mazdaverx7]

with the 3VZ-FE, you shoud be running 92 or higher, per the manual. not that it will make a huge difference, but the tire pressure specs are 32psi front and rear.

[ivan300]

91 RON = 87 Octane

If im not beating on there is no reason to use premium.

[mazdaverx7]

i wanted to add that removing the fuel injectors and sending them in to be cleaned may really restore performance and economy. i use a company called witchhunter performance. their turn around is only about five business days and their work is outstanding!! their website is www.witchhunter.com

[EEngineer]

yea there's no point in dumping premium in 3vz

[mazdaverx7]

Originally Posted by ivan300

91 RON = 87 Octane

If im not beating on there is no reason to use premium.

and that may be fine. i always go by the book and use 93 octane and my fuel mileage numbers are consistant. i wouldn't think that octane rating would really make that big of a difference from your 13mpg to a factory quoted 18mpg city.

[mazdaverx7]

Originally Posted by EEngineer

yea there's no point in dumping premium in 3vz

even with a 9.6:1 compression ratio, there actually is a point. the engine will run far better and performance will increase. the ecu can recognize higher octane fuel and will adjust the timing based on the octance level. the higher octane fuels are better for your engine and the internal engine components such as the valves and pistons, will be cleaner because there are more cleaning agents in the higher octane fuels.