'89 Corolla trouble code #25? (carbureted California car)

Hi all,
1989 Toyota Corolla SR5, Carbureted 4AF, California emissions, 146k
miles, runs great, thanks largely to all the help I've gotten from this
newsgroup since buying the car in 1999.

Check Engine Light turned on while I was driving (stop and go local
driving)-- I pulled the trouble code and it's #25. Runs fine. Engine
temp was normal operating temp. Came home. 15 minutes later, for good
luck, I sprayed some carb cleaner in the carb. Drove the car around a
few miles, the check engine light did not come back on.

Could someone tell me what this code is and what I might want to do
next? From what I could find from old posts, it may mean "running
lean" and that the next step is to change the O2 sensor? (or can it be
cleaned?)

If so, does anyone know if a California car would use the same O2
sensor as a non-California car?

The only other history of relevance, if any:
1. gas mileage is normal; passed Emissions fine 5 months/2000 miles ago
2. had entire new exhaust system installed last month, including new
catalytic converter.
3. 5 years/40,000 miles ago, the car was misfiring when cold and had
trouble codes #31 and #41. I first changed the Thermo vacuum switching
valve, which did not help. Then changed the Throttle position switch,
which solved the problem.
4. car's now only driven about 4k miles a year, mostly local driving
5. it is getting colder quickly here in Boston

Hope it's unlikely that the car needs a new carb, b/c I just put $1100
into it this past year and will go crazy if I need to spend any more on
it.

Thanks for any and all advice!
John

wrote in message

> Hi all,
> 1989 Toyota Corolla SR5, Carbureted 4AF, California emissions, 146k
> miles, runs great, thanks largely to all the help I've gotten from this
> newsgroup since buying the car in 1999.
>
> Check Engine Light turned on while I was driving (stop and go local
> driving)-- I pulled the trouble code and it's #25. Runs fine. Engine
> temp was normal operating temp. Came home. 15 minutes later, for good
> luck, I sprayed some carb cleaner in the carb. Drove the car around a
> few miles, the check engine light did not come back on.
>
> Could someone tell me what this code is and what I might want to do
> next? From what I could find from old posts, it may mean "running
> lean" and that the next step is to change the O2 sensor? (or can it be
> cleaned?)
>
> If so, does anyone know if a California car would use the same O2
> sensor as a non-California car?
>
> The only other history of relevance, if any:
> 1. gas mileage is normal; passed Emissions fine 5 months/2000 miles ago
> 2. had entire new exhaust system installed last month, including new
> catalytic converter.
> 3. 5 years/40,000 miles ago, the car was misfiring when cold and had
> trouble codes #31 and #41. I first changed the Thermo vacuum switching
> valve, which did not help. Then changed the Throttle position switch,
> which solved the problem.
> 4. car's now only driven about 4k miles a year, mostly local driving
> 5. it is getting colder quickly here in Boston
>
> Hope it's unlikely that the car needs a new carb, b/c I just put $1100
> into it this past year and will go crazy if I need to spend any more on
> it.
>
> Thanks for any and all advice!
> John
>
>

I did not check to see if trouble code 25 means that the engine is running
lean, but assuming it is, spraying carb cleaner enriches the mixture.

Check to make sure the air filter is not dirty. Remove the air filter
element and shine a light behind it. You should be able to clearly see the
light through the element. If the light is dim or not visible, replace the
air filter element.

The system knows it is lean from the O2 sensor's output, so I would start by
checking O2 sensor function. Disconnect the O2 sensor and hook a volt meter
up to the sensor terminals. With the engine running steady at about 2,500
RPM, voltage should fluctuate at least once per second. If it does not,
then the sensor needs replacement. I do not know if CA vehicles have a
different O2 sensor or not, but I suspect not.

If the O2 sensor is functioning properly, then the carb needs adjustment. I
would leave this to a competent technician.
--

Ray O
(correct punctuation to reply)