ITSAXA

I just got 260 miles on the tank. 8.4 galloons went back in (2 clicks)
Tyhats over 30 mpg heavy foot in the city driving.

Thats twice now...I love it

way to go scion.

GooseNaBoxxx

32avg mpg
lowest=29
highest=37
i have a slightly heavy foot, but I have the AEM intake and a Borla axleback exhaust (if that makes a difference)

Jan06xB

x_rayted711 - Check the gas pump and see if you are getting the ethanol (E85) in your gas - that will kill mileage. Run some STP gas treatment in the tank also. Tire pressure check too! Should be 29 lbs. Check the tail pipe if it is sooty you have a problem - should be covered by the warrentee. If you are using your brakes a lot then all bets are off but the hesitation indicates a problem. I stabbed mine yesterday pulling out in first gear and the wheels starting spinning like crazy and it was 32 degrees out and the engine was cold. Last tank of gas was 433.5 miles 10.81 gallons - do the math - 2100 miles on mine.

x_rayted711

I will check the pump as I don't know what it is...

I have run two bottles of injector cleaner (within a month...not at the same time)

I check the tires once a week and they are always at 36 (17"...not OEM size)

There is no soot on the tailpipe.

It WILL NOT spin the tires...no matter what...trac off, in low gear, it won't do it.

Jan06xB

hey here's a good question - have you checked the odometer - is your tire diameter larger than stock affecting the drive ratio and odometer reading? larger diameter tires would do that. It can affect the traction control and abs also. My odometer is about 10% less than actual meaning I get about 44mpg with the stock tires. If you have wider tires with a sticky compound don't worry about not spinning them - sucks when you step on the gas and nothing happens and you need to get out of the way. 36 psi is good - my dealer had mine at 42 but said they were at 32 - I lowered them to 38 and they ride pretty hard - may have to go lower in the snow.

x_rayted711

I did a TON of research on the tires before I bought them and they are within 1/2" of stock diameter. Also, this is a problem that started in Oct and we have had the tires/wheels since May.

Jan06xB

Your variable valve timing is stuck - it is controlled by the car computer with an electric controlled valve driving a hydralic timing sprocket on the timing chain on the cam. I have heard that the cpu can be reset back to factory defaults in case it has learned / adjusted engine parameters that are not working properly. Its the only thing that can effect performance and economy and still have the engine burn clean.

x_rayted711

^^^ So wouldn't this throw a check engine light? And how do I get it back? Resetting the ECU? I have already rest it once about 6 weeks ago.

spawnconnery

Whats this "not being able to spin the tires" business? Its an automatic, right? I wouldnt even try to spin the tires on mine with it being an auto. If its raining and I put the foot to the floor from a dead stop, one wheel might spin.

x_rayted711

^^^Yes, it is an automatic. I was seeing if it did indeed bog or sputter or anything. I came to a complete stop, turned the trac off, put it in low and just nailed the throttle to the floor. The road was slightly wet (misting outside, not raining).
I hear of people and have seen pics of people doing burn outs, and although I think it's kind of rediculous with this particular car, I wanted to see if it was possible. It is NOT possible with MY car. LOL. So, with that 'test' out of the way, is that normal for the auto xB to not spin the tires? I rented an Echo a year ago and that thing screamed for what it was. Much peppier than my xb.

jct

echo is lighter then a xB

x_rayted711

Yes, I know...I made a mistake when we were looking at the xB by saying "it's the same drivetrain as that Echo we rented for 2 weeks...and THAT car was pretty peppy for what is was, so the xB will be the same...." Boy was I wrong! LOL.

Jan06xB

I really thing you have some kind of valve timing problem - as far as the spinning in first gear - my standard xB has slightly different gearing 29mph at red line in 1st - compare that to your gearing in the owners manual. But I spin my wheels easily without any cluch slipping or dumping to break them loose. Even my 94Geo would do it and if I hit second I could get a chirp out of it too - if it was a little wet I could sit and spin all I want in second gear. As far as the valve timing I don't know if there is an easy way to check it.

Clip from:
http://scion-tech.com/zerothread?id=63&postid=3178

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.

x_rayted711

How can I tell if it is working as it is supposed to? Your staement makes sense about it still burning clean. I just don't know how to check it.

Shouldn't it have thrown a code if it was or is faulty?

Should I reset the ECU again to see if anything changes?

If resetting the ECU didn't work (which it didn't last time), is it possible for the problem to be mechanical (I know it is controlled by the ECU, but the ECU has to control a mechanical device). How can I troubleshoot it?

Jan06xB

That's my point - there is no feed back to the computer as far as I can tell from the engine cam shaft if it did move as it was supposed to or not. The only way would be to have the valve timing checked through the oil filler cap - I don't even know if you can see the valves from there - unless there are external timing marks on the cam shaft which could be checked. Could be that you are locked in the start timing position and it will not release. Reseting the ECU will not have much if any effect on this if it is a mechanical problem. Maybe a good engine tech could manually advance and retard the timing by activating the control wires on the solenoid - I have not had the time to poke around under the hood much to know exactly - kinda cold and snowy around here since the blizzard this past weekend.

Still think you should check your gas at the pump - I use Hess and fnd that I get much better gas mileage with it than other brands. The E85 website makes it sound great but I wonder what they mean by "slightly lower"...

http://www.cleanairchoice.org/outdoor/E85Background.asp

"E85 also contains lower energy density than gasoline (BTUs per gallon). Typically, its lower pump price offsets a slightly lower fuel economy."

Duker

My Xa is at 174 miles to a half tank right now. Im using 93 octane REAL gas. not the reformulated crap they sell around here.
Now i think i know what the real problem is

hotbox05

um even with the added weight at least as far as manual transmission equipped cars the scions are faster since their gearing is better.

hotbox05

what the hell is hess? what the hell is real gas? i dont think 4-5 mpg is better if you have to pay 20-50 more cents per gallon.

Jan06xB

x_rayted711 Hey I talked to my brother today and he thinks there is some timing sensors on the cam shaft to control when the injectors fire so there may be a way for Scion Techs to check your valve timing without opening up the engine just by checking the ECU on the diag port. My ScanGauge does not read any valve timing only ignition timing. Brother is a retired Navy Flight Engineer and has works on million $ engines and the expensive FAST cars that have names I can't spell so he knows his stuff. Maybe you should ask the service manager if they have any way of checking the variable valve timing and explain your drop in gas mileage - show concern that you are worried about something going wrong with the engine and if they can check it before it blows up or something. I am sure they would not want to do a valve job on the engine if it throws a cam shaft.

x_rayted711

^^^ THX. I'll look into it, but I have been to the dealer twice on this subject and I ran an OBDII thing on it...It showed nothing. Whatever it is, it isn't messing with the ECU or anything that the ECU can monitor.
I really hate to even take it back to the dealer near me...They kinda suck, but oh well.

I am headed back to Louisiana and hopefully the mileage will somewhat correct itself on the freeway, but I wish I knew how far I could get between fill-ups BEFORE we head out. If the mileage is still crappy, we will take it to the dealer near us there.

On a side note, we went to Fairfield/Vacaville this past weekend and the mileage hit an ALL TIME HIGH (since Oct. anyway) of 26.95 MPG after we got back and refilled...so maybe the freeway will do it some good. That is the best mileage I've seen since this crap started.

Thanks again for the info and I will get it checked or at least ask about it when we get home.