Half tank 70 miles

I have replaced
Spark plugs(ngk, iradium) + wires + cap
air filter
fuel filter
used choke/ carb cleaning of trottle body, little bit of intake manifold
changed my oil(silly but did so anyway)
checked all exhaust for leaks

let's see uhm....well my warms idle goes at 900 rpm
i just couldn't find my reason why my mpg goes down that bad
and so sudden. let's see,
i check my spark plug and found carbons around the rings and inside
which means that
my engine is running rich on gas.....

2 things that i think might be wrong uhm...
timing probably needs to be adjusted
coolant sensor need to be replaced
(the sensor that goes on top of the wateroutlet that flows from the radiator to the engine, and the has 2 long easy breakable green/blue tube on top)

anybody know what eles can be wrong?
my mpg is killing me 80-70 for half tank(city)

Have you changed petrol stations? I find my Celica does better on some brands of petrol than others.

Try resetting the ECU, I had similar bad fueling till someone suggested reseting the ECU. I got a 200% increase in fuel economy after doing that.

You could try bridging the coolant sensor with a bit of wire. Also newer Celicas retard the timing to protect the engine when something is wrong, not sure if the older ones do that.

my guess would either the O2 sensors or valves, but your valves can't be that badly out of adjustment. Myabe a combo of both. You're probably going to need your O2 sensores to be checked out.

getting new o2 sesnors(1 wire)...
i hope that helps.....
what's funny is that my car has the California
sensor(2 wire one) located below the main o2 sensor, i hope i don't have to replace that too.
valve adjustment is expensive i'll see if the new o2 sensor improve + the overnight reset of ecu

is your engine DOHC or SOHC? If it's SOHC it's fairly easy since your cams should be pointing right at you. Just find a buddy to help you with the process, it's pretty easy actually, just need large wrench for the crank, smaller wrenches for the valves and a feeler gage. Of course you'll need to find out what is suitable gaping for your engine. But it's nothing that hard.

my o2 sensor arrived yesterday.
What a fix, and it only cost me 13 bucks
for that new o2 sensor (ebay)
I reset my ecu(overnight) and put on that new o2 sensor
Guess what guys...now my get 190 miles at half the tank
instead of 70 miles... WOW
i'm cured!!!!!!! thanks to everybody who helped me get thru this.

O2 senser huh...i got my celica thursday and i already put in 15 in gas to go about MAYBE 70 miles...good calll everyone. Thanks!

how to reset the ecu??????

how to reset the ecu??????
pull out the ECU fuse and leave it for an 30 mins/hour, put it back in.

Celica newbie-> how many miles are you supposed to get for a full tank? I have a 89 GT auto.

I get about 260 miles to a full tank, you should get maybe 400 miles in a non-turbo car, mixed driving.

I get about 260 miles to a full tank, you should get maybe 400 miles in a non-turbo car, mixed driving.

Hmm...i hope so. I'm low on cash and it says that its 5/8ths full at 130 something miles. I hope i can squeeze out another 70 from that little bit, but it doesn't seem likely. It would be great to have a 400 mile car :-D. Esp since i don't have my job yet.

woh wtf...im getting only 200 miles to a full tank of gas..,

oh this is bad. If im suppose to get around 400 then wtf is wrong. I reset my ecu and got a small increase *(about 40miles) but what else is there...the spark plugs are new, new distributor cap, new intake filter (sqaure).

I need to check the air filter but what else should i check?

I have a 1990 Toyota Celica ST so i know i should be getting around 350 miles.

Air sensor***

Celica`s are covered in sensors, when any one of them goes wrong or detects a problem it retards the timing and puts the engine into kind of a "safe" running mode. check your error codes if its possible to do that on a 1990ST? Not sure if you have a Knock sensor on the ST model (its behind cylinder 3) but they are prone to going wrong and will f-up your fueling.

instead of puiing out ur fuse you could just discnnect ur posotive barrtey cable for a couple seconds then put it back on, that resets ur ecu as well

yea 02 is the #1 problem for bad gas mielage and no smog pass, tobe honest im replacing min this weekedn along with soome new bondo on my car and exhaust.....i hate ilegals

GAH. Okay, i'm starting an experiment now. I averaged 23.4449 Miles per gallon. At first i thought that was great and i was happy, but then i saw i should be getting 26-32. Then i realized what overdrive was for and felt like an idiot. So now we're goign to see the difference between O/D and non O/D driving habits. Funny thing about this car is that it goes into first gar without me touching the gas pedal and drives at 15-20 miles per hour. I don't know if it saves gas ro what, but tis pretty cool to me that it does that. In a week, i'll update on an O/D mpg. Oh, and please, help me on my other threads. I really need it.

I get about 260 miles to a full tank, you should get maybe 400 miles in a non-turbo car, mixed driving.

I'm getting 360:-P. I'm trying it with overdrive engaged now. All i can say is i already see a speed increase

yea hey i only got about 200 miles outta my st as well till i replaced my o2 snesor, mind you tho i have a california st

well the ram intake i put on has increased my milage from around 200 to 320....which is much better...but where is the o2 sensor located on the st?

wow, the only way taht can happen is if your old air filter was clogged to shit...

So i should probably check my air filters if i'm getting around 360 mpg? To be honest, i did the cacluations based on it being a 15 gallon tank. How many gallons IS the 89 celica tank?

no i dont think it was the filter, i think the tubes were clogged, i didnt remove the tube that goes under the headlight, i left it...but i think that is what was clogged


also my o2 sensor needs changed...but where is it located? is it the piece that was in the airbox? or is it somehwere else on the engine?

o2 sensor comes from the ex manifold (upper) looks kinda like a sparkplug. in the airbos is the airflo sensor

^correctomundo

toyota says the tanks for our cars are aronud 15 gallons (15.7 for me)

but ive NEVER put more then 12 gallons in, i was ABONE dry like it was chocking and i only put in 12.7 gallons or sumthin like taht....usually i only put it about 10 gallons when i have abotu an 1/8 of a tank (halfway between the 0 and the 1/4 dash)

yeah ive never put more than 11 gallons in.....how the hell do they get a 15.7 gallon tank? I know you can never dry out your tank completely without fucking up the fuel pump, but ive never put in more than 11

to tell u the truth the pump isnt what you have to worry about, its the booy thing in the gas tank that reads how many gallons yhou have left...the thing that tells you how much gas you have, if you run dry it will break and the only way to fix it is to have a whole new gas tank instaled..... ouch

Grr...now i'm kinda pissed. I have 24.07 MPG, even with overdrive. I now believe that my tank is 13 gallons. I only get just over 300 miles. So far, the air filter and the O2 sensor are suggested for replacement, any others? what's a good price for these things?

^correctomundo

toyota says the tanks for our cars are aronud 15 gallons (15.7 for me)

but ive NEVER put more then 12 gallons in, i was ABONE dry like it was chocking and i only put in 12.7 gallons or sumthin like taht....usually i only put it about 10 gallons when i have abotu an 1/8 of a tank (halfway between the 0 and the 1/4 dash)

Okay, so you aren't supposed to go completely dry? Two nights ago i put in ~12.7 with the gas light on. Oh, can someone PLEASE tell me what the warning light between the gas light and the O/D off light is on an 89 celica. Its been on since i got the car and i have noooo freaking idea what it means. Its kinda annoying since is a constant reminded of my ignorance of my new car...like me not being able to use more than 12.7 gallons per tank...

Ah well, atleast i'm learning fast... :smokin:

Well, with gas prices on the trend that they are, it soon may become more economical for me to train into school than drive. Yes, i'm being absolutely serious on that one. :headshake Cryin' shame...

um yea a word of warning to all cleica drivers, NEVER DRIVE AROUDN ON THE GAS LIGHT...taking a large bump, or going up a kill can fuck up your tank sensor, immidiatly as you see that light come on, go get gas, its bad to drive on that low neway cuz u start sucking up all the crap in the bottem of ur gas tank (yes dirt and shit does get in therr)

Haha, are you serious? yeah, i don't know how much gas was left while the gas lights was going, so i spent a good 30 mins at 11PM hitting all the cheap gas stations to see if the were open. Grit and sand at the bottom...geez. sucks when ya po' and ya tank is low... with prices going so high, the gas you want, ya can't get, and the gas you go, you ain't want.. :smokin: