1989 Tercel Acceleration (Carburetor O-Rings? Carbon in Intake?!)

toyota
tercel

#1

I have a problem with my '89 Tercel. When I accelerate, but the torque of the acceleration is hindered at first, like not enough/too much gas is getting to the engine, and if I keep the gas pedal lightly pressed, around 2500-3000 RPMs, the car will suddenly gain torque, and I’ll have some power behind the engine. If I push hard on the accelerator, the car seems flooded, and then jumps to 3000-4000 RPMs. It isn’t as noticable in 3rd or 4th (probably because I’m consciously shifting at a higher RPM to avoid the problem) unless I’m going up hill.
I have read a number of forum posts on this problem.
Half say it’s a problem with carbon in the intake/outtake manifolds of the exhaust. The other half say it’s a carburetor problem regarding the o-rings.
I’m a new owner of the car. It has 210,000 miles, and I’m not sure if it has sat for a while.
Just trying to get 20th opinions here.
Any help is appreciated.


#2

You may disregard the but in the second sentence. (blushes)


#3

The 89 Tercel is fuel injected, so carburetor problems are out of the question. I would have the O2 sensor checked, it is not monitored by the computer. There should be a 2 pin connector near the distributor that has a cap on it. You remove the cap and use an analog voltmeter on the two pins to see if the voltage sweeps between 0-1 volt about every few seconds.


#4

The carburetor would be my first guess. Your car has a different type of carburetor, it’s called a “variable venturi” carburetor and will require someone familiar with this type of fuel system to properly diagnose and repair.


#5

It sounds like a too-lean condition. At 210K miles, could be caused by lots of things. You may simply need a replacement carb (if you car has one, from the posts above seems ambiguous). My first guess would be a vacuum hose or device leak or a faulty EGR system.

Do you have the factory shop manual or a Chiltons for you car? That would be a place to look to for inexpensive diagnostic advice for this problem.


#6

If this Tercel was sold in the US, then it has a 4AFE engine which is fuel injected, not carbureted. The 4AFE was a smaller, detuned version of the famous 4AGE engines of the popular AE86 Corolla’s. The last Tercel with a carburetor was the 88 4WD wagon and it had a progressive two barrel carburetor, not a variable venturi. All other Tercels got the fuel injected engine starting in 87. All his symptoms point to the oxygen sensor.


#7

89 and 90 had carbs. overhauling VV carb on one today . Several things could be causing the issue . Make sure venturi slide is free and opening as RPM increases .


#8

I would hope after this much time the Original Poster would have solved their problem.


#9