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Discussion Starter · #1 ·
Does anyone know of a way to ensure that the VVTi system is working properly? Will the ECU throw a code if it isn't working properly?
 

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yea it will likely throw a code in a certain chamber if its in the piston and misfiring. or if its running too lean or too rich itll throw a code. if somethings wrong, the computer will likely tell you.

scotty
 

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Discussion Starter · #3 ·
Well, I ask because someone in another forum suggested that it may be the problem with my horrible fuel mileage (VVTi not activating or stuck and may cause it to get bad mileage but still have a good emissions test, which it does). My check engine light hasn't come on, but I was wondering if it would or not if there was a problem.
 

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the good thing about vvt-i from my understanding is its electric, unlike other valve systems (such as vtec (variable valve timing with electonic lift control) on the hondas which is engaged by an oil pressure sensor)....so being an electronic all time running system, it should throw a CEL when it is not engaging properly, the only bad part, is I'm not sure of a way to tell yourself if its running or not since its all time running (hence the "i"-with intellegence) and not like once again vtec that has a certain pressure it engages and you can actually hear it kick in....

the cai is the only performance mod you have? how about any asthtic mods (the gas milleage could be caused from anything to larger rims, to and body kits causing draft...not much, but still a factor to look into)....also, have you checked your AEM filter to see if its dirty....if its really dirty, its like you trying to breath with a bag over your head, you sufficate and use more energy, a motor is like a huge vacuum, and to work properly, both sides must be free ;)
 

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not too long ago i was hitting 35 in the city. thats with custom exhaust, intake, lowered, and steelies. right now im probably only around 30 though.

scotty
 

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Discussion Starter · #9 ·
^^^ 21-22 MPG. And as far as any mods we've done....everything had been on there for months before and we were getting 30 city 35 hwy...This last October is when it dropped and stayed low. I ran an obdII on it today and it showed nothing ( I figured, since the engine light is off).

I was told (and read) that the VVTi is ran by oil, not electronics. I'll see if I can find the link.
 

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Discussion Starter · #10 · (Edited)
Here it is Suspended...Not the link, but the part I read....

VVT-i Activation:
the scion's VVT-i is a computer controlled and oil-pressure activated push- push type system. The engine ECU can command the system to advance or retard the inlet camshaft timing, thereby providing for faster response. The hardware is a camshaft timing oil control valve mounted adjacent to the inlet camshaft gear wheel and a VVT-i controller mechanism built onto the inlet camshaft timing gear. The camshaft timing oil control valve is a spool valve, controlled via a coil and plunger by the engine ECU. It can signal "advance", "hold" or "retard". The VVT-i controller consists of a housing on the front of the timing wheel, driven from the timing chain, and a four-bladed vane coupled with the intake camshaft.
 

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wow, i heard wrong about the vvt-i then, from what I heard, it was an all running valve timing run by electrics, not oil pressure....i'll have to look into that more in depth =/
 

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Something's gotta be up with that mpg, I mean that's how much I get with my turbo when I use it generously. When I am in my "gas saving" mode, I get around 23-24. Dirtyrice, maybe you should try the "unplugging of the efi fuse and plugging it back in after 15 minutes or so" technique and then fill your tank and try to measure your mpg again.
 

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Discussion Starter · #15 ·
Well, I drive 6 miles (drop my wife off at work and drive home, 3 there 3 back) twice a day. I rarely go over 40 MPH. The car is empty other than us.

I have tried driving with the Trac off, OD off...
 

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so your not "dogging" the motor, like keeping it in high rpms before shifts?
 

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Discussion Starter · #17 ·
No, hardly ever. I think part of the problem is the RPM is TOO low. When I slow for traffic or a light, then get back on the gas, it either stays in the gear it was in and SLOWLY get back to speed, or it will stay in the gear it was in and then (after holding it to the floor for a couple seconds) finally downshift to a lower gear.

I read somewhere that the most efficient RPM is 70% of the max torque RPM.

Also, sometimes I find myself doing 30 MPH in OD?!?! And as stated above, when I need to get out of someone's way or change lanes or whatever, it takes forever to either get going or downshift (or both!).
 

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dirtyrice said:
Well, I drive 6 miles (drop my wife off at work and drive home, 3 there 3 back) twice a day. I rarely go over 40 MPH. The car is empty other than us.

I have tried driving with the Trac off, OD off...
I do the same amount of driving, well a little less. I get 24-25mpg. It's the starting and stopping that is killing our gas mileage. But I have a header, pulley, intake, axle-back.

But if it was getting 30mpg a couple months back, I don't know. Maybe your filter is dirty, and needs cleaned.

I've had my box since December of 04' and still haven't hit the 10,000 mile mark.
 

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Intresting. I wonder... I've had mine since Jan of 04. With 18'S, DC Header, high flow cat, manifold back exhaust and the AEM cai, I was getting about 210 miles per tank.

Now I have the Weapon R short ram, stock exhaust, stock headers, and steelies and I can squeeze out about 315 per tank.

(mostly freeway commute, some stop and go.)

Is that about normal? oh and I'm at 41K.
 

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Discussion Starter · #20 ·
I WISH I was getting 300+ miles per tank again! It did when we got it and all the mods we have on it have been on it since day one pretty much. The highest we had was 340 on one tank, but it's been awhile. The best we've had since October was 240 or so...and that was with 20-30 miles after the low fuel light came on. I think it took like 10.9 gallons, but was a while ago, so I can't be sure of the exact numbers.
 
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