I was assuming that the Tercel 3AC fuel setup defaulted to RICH when something involved in mixture control...like the O2 sensor fails....but have read recently on Google the opinion that it defaults to LEAN.
If so...this might explain the good MPG I get with an O2 sensor that probably isn't working...so if I replace it...my MPG goes down?
<span style='color:blue'>Can anyone answer this question??????</span>
Tercel carb-emissions question...
My '83 3AC has an O2 sensor and a carb. Some cars were made with this combo.
Concerned because I've put a new one on and am worried about losing MPG with a working O2 sensor.
With a non-working (old?) O2 sensor, I get LESS mileage (by 10%) when my EGR is also working....
Concerned because I've put a new one on and am worried about losing MPG with a working O2 sensor.
With a non-working (old?) O2 sensor, I get LESS mileage (by 10%) when my EGR is also working....
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
takza,
When I had my 83, before it went to junkyard heaven
, it got 30-35 mpg and it also had a carb and 02 sensor. I never replaced it though so it could have stopped functioning somewhere between 40K and 300K miles :unsure: I think the EGR allows rich gasses in to the carb and the O2 sensor would see rich and tell the computer to lean the fuel mixture. So you might see an increase with mpg with a working EGR and O2 sensor. Also, doesn't C in 3A-C stand for California emissions?
When I had my 83, before it went to junkyard heaven
, it got 30-35 mpg and it also had a carb and 02 sensor. I never replaced it though so it could have stopped functioning somewhere between 40K and 300K miles :unsure: I think the EGR allows rich gasses in to the carb and the O2 sensor would see rich and tell the computer to lean the fuel mixture. So you might see an increase with mpg with a working EGR and O2 sensor. Also, doesn't C in 3A-C stand for California emissions?“How did I get here, this is not my lifeâ€
3-AC is just the engine type or designation.....there were the Federal...California...Canada versions in North Am?
The EGR LEANS the mixture when it recirculates exhaust gases into the intake.
I'll find out soon...since I have the O2 sensor in and the EGR working...we'll see what it does...I'm guessing less mileage.
The EGR LEANS the mixture when it recirculates exhaust gases into the intake.
I'll find out soon...since I have the O2 sensor in and the EGR working...we'll see what it does...I'm guessing less mileage.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
I've thought that the 3AC meant California emissions, until I thought I saw a tercel that had federal emission stuff, but was a 3AC....
Yeah, there were Federal, California, Canada versions in N. America. The main differences came in the emissions equipment, but the changes were slight.
You have to be careful, just because the sticker on the valve cover says 3AC doesn't mean it's a 3AC.
takza, if you are correct, then you will have to write up a repair guide on how to break the O2 sensor!
Yeah, there were Federal, California, Canada versions in N. America. The main differences came in the emissions equipment, but the changes were slight.
You have to be careful, just because the sticker on the valve cover says 3AC doesn't mean it's a 3AC.
takza, if you are correct, then you will have to write up a repair guide on how to break the O2 sensor!
It wasn't too bad a job...soaked the 2 bolts in PCBlaster for 24 hours...used a Bosch sensor that cost $30...had to splice the wire to it...used anti-seize to install it. Started it up but haven't been out on the road yet.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
I can't drive my car currently with the EGR going...after I put the new O2 sensor in...it made the car undriveable below 1500 RPM or so....too much exhaust gas I guess...suspect the vac modulator is bad????
Before I put in the O2, the EGR worked OK, car drove OK...lost MPG and power though.
Before I put in the O2, the EGR worked OK, car drove OK...lost MPG and power though.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Found a page on '83-'87 Tercel emssions problems:
<a href='http://www.aircarecolorado.com/repair/toyota.htm' target='_blank'>http://www.aircarecolorado.com/repair/toyota.htm</a>
"...DTEC contacted several of the Toyota Master Technicians in the area. Each technician identified the most likely causes of failure as the oxygen sensor, vacuum hose routing or degradation, vacuum switch operation, EBCV contamination, and carburetor overhaul. All of the technicians interviewed had attended EDGE training but commented that Toyota did not offer specific diagnostic information for the feedback-carbureted systems."
"Of the three vehicles identified as repaired properly, one required an oxygen sensor, one required a thermo-vacuum switching valve and the third required an oxygen sensor replacement and EBCV disassembly and cleaning. "
"Vehicle #1 required cleaning the EBCV, repairing a connector, and replacing several clogged vacuum lines. Vehicle #2 needed a TPS and an oxygen sensor. This was a recently-waived vehicle with a new catalytic converter. Vehicle #3 required a new oxygen sensor, repairing a broken vacuum line, and overhauling the carburetor. The results indicate repairing the system to operate as designed will result in a successful repair."
<a href='http://www.aircarecolorado.com/repair/toyota.htm' target='_blank'>http://www.aircarecolorado.com/repair/toyota.htm</a>
"...DTEC contacted several of the Toyota Master Technicians in the area. Each technician identified the most likely causes of failure as the oxygen sensor, vacuum hose routing or degradation, vacuum switch operation, EBCV contamination, and carburetor overhaul. All of the technicians interviewed had attended EDGE training but commented that Toyota did not offer specific diagnostic information for the feedback-carbureted systems."
"Of the three vehicles identified as repaired properly, one required an oxygen sensor, one required a thermo-vacuum switching valve and the third required an oxygen sensor replacement and EBCV disassembly and cleaning. "
"Vehicle #1 required cleaning the EBCV, repairing a connector, and replacing several clogged vacuum lines. Vehicle #2 needed a TPS and an oxygen sensor. This was a recently-waived vehicle with a new catalytic converter. Vehicle #3 required a new oxygen sensor, repairing a broken vacuum line, and overhauling the carburetor. The results indicate repairing the system to operate as designed will result in a successful repair."
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Electrostripping is the reverse of electroplating??? New one on me.......JIMCAT wrote: I will clean my EGR this weekend by electrostripping. Should be easier than all that soaking and scraping you did.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Some INFO from hyperspace:
"I have a 83' Tercel wagon, 130K, and been having progressively worse cold start behavior over the course of this winter. The car will start every time but it takes a few attempts as it dies almost immediately and usually have to pump the gas to get it to "catch". For the first 30 sec or so after starting the engine sounds rough but the exhaust is clean. But then the exhaust gets VERY smokey and smelly (engine is still rough). I can leave the car for 5-10 minutes to warm up and it doesn't help at all - the exhaust is still terrible. All that seem to help is to get in and drive it for a couple of miles, after which it is fine and the exhaust is clean again."
<span style='color:blue'>Sounds like a broken AAP diaphram, this is the "auxillary accelerator pump" and is vacuum operated, with a ruptured diaphram, it just allows the engine to eat raw fuel, the TVSS turns it off after engine temp is normal, this would explain it being gone after its warm. Look for the cover to the AAP its held on the carb by three screws, just temporarily dissconect and plug the vacuum hose for now until you get a new diaphram. </span>
Q: My 83 Toyota truck is hard on gas, about 25 MPG on the highway. Is this normal? I have gobs of oil in the oil filler cap, why?
A: Your fuel mileage is a little low. Several things can cause this, valve adjustment , the condition of the Ignition system, carb float level (too high causes more fuel to be used), <span style='color:blue'>the power valve in the carb may be leaking (this also caused harder starting after sitting). </span> If all of these are in good condition then enjoy your truck, remember its 15 years old. Your second question is a case of engine breathing and normal operating temperatures. If the crankcase vent system PCV is not free and working then moisture is the a result. If the thermostat is not allowing the engine to get to a normal operating temp then water vapor will gather in the oil fill cap.
"I have a 83' Tercel wagon, 130K, and been having progressively worse cold start behavior over the course of this winter. The car will start every time but it takes a few attempts as it dies almost immediately and usually have to pump the gas to get it to "catch". For the first 30 sec or so after starting the engine sounds rough but the exhaust is clean. But then the exhaust gets VERY smokey and smelly (engine is still rough). I can leave the car for 5-10 minutes to warm up and it doesn't help at all - the exhaust is still terrible. All that seem to help is to get in and drive it for a couple of miles, after which it is fine and the exhaust is clean again."
<span style='color:blue'>Sounds like a broken AAP diaphram, this is the "auxillary accelerator pump" and is vacuum operated, with a ruptured diaphram, it just allows the engine to eat raw fuel, the TVSS turns it off after engine temp is normal, this would explain it being gone after its warm. Look for the cover to the AAP its held on the carb by three screws, just temporarily dissconect and plug the vacuum hose for now until you get a new diaphram. </span>
Q: My 83 Toyota truck is hard on gas, about 25 MPG on the highway. Is this normal? I have gobs of oil in the oil filler cap, why?
A: Your fuel mileage is a little low. Several things can cause this, valve adjustment , the condition of the Ignition system, carb float level (too high causes more fuel to be used), <span style='color:blue'>the power valve in the carb may be leaking (this also caused harder starting after sitting). </span> If all of these are in good condition then enjoy your truck, remember its 15 years old. Your second question is a case of engine breathing and normal operating temperatures. If the crankcase vent system PCV is not free and working then moisture is the a result. If the thermostat is not allowing the engine to get to a normal operating temp then water vapor will gather in the oil fill cap.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
<a href='http://users.eastlink.ca/~pspencer/nsae ... lysis.html' target='_blank'>http://users.eastlink.ca/~pspencer/nsae ... is.html</a>
"Try it. You'll like it."
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