93 Runner Ck Engine Light

My 93 4 runner and has a check engine light, I got a code 25 Air-Fuel ratio lean malfunction. Any suggestions as to were to start would be helpful. The list of possible problems is long. Inj sys, inj, fuel line press, ignit sys, O2 sensor sys, O2 sensor, air flow meter, Water temp sensor, ECU. Any help would be appreciated.

Have you tried www.obd-codes.com?

Thanks ctwright, I will check it out.

I checked the OBD website but doesnt help. I dont have the OBD system on the 93, its the ECU, count the ck engine light flashes to get the code number. Any idea which system might be causing the light? Anyone ever have this before that may give me a starting point?

the site provided is for OBD II 1995+ models... your vehicle has OBD I, which you already know by jumping the connector and reading the flashing light to spit out that code...

clear the codes and see if they return:

Remove the EFI fuse (15A) for 30 seconds with the ignition switch OFF to clear any codes. It may take longer than 30 seconds, depending on ambient temperature (the lower the temperature, the longer the fuse must be left out).

Trouble codes can also be cleared by disconnecting the vehicle battery. However, other memory functions (clock, radio, etc.), will need to be reset.

After the codes are cleared, road test the vehicle (as applicable for the fault) and recheck if any codes reset.

common sense thinking: when's the last time you change the fuel filter? running lean means less fuel is entering the combustion chamber; that's one possible dart in your problem...

another possibility is to check those vacuum hoses under the hood... or even the intake manifold... more air than gas int the air-fuel mix would cause this as well

another one:

the system lean condition is caused by the engine misfire and that is the root cause of the problem, the misfire must be corrected first, the check engine light flashing is an indication that the misfire is severe enough to damage the catalityc converter if not fixed.

so w/ his input, check spark plugs/ignition coil ?!?

Thanks ricebike, I recently bought the vehicle and haven't had a chance to change fluids and filters yet. I do known the previous owner had the air intake off to change valve cover gaskets. I wonder if he missed a vaccumm line or has a slight leak in the air intake. I reset the light last night and will drive it tonight and see if it returns. Thanks again for your help.

Measure the voltages and resistances on the ECU (EFI computer) and compare with the FSM (factory service manual) to isolate problem.

Free 1990-1995 Toyota 4-Runner Factory Service Manual:

http://www.ncttora.com/fsm/1990-1995_4Rnr/Toyota.4Runner.1990.1995/contents.htm
http://www.ncttora.com/fsm/1990-1995_4Rnr/Toyota.4Runner.1990.1995.zip
http://forums.bauchan.org/portal/viewdownloads.php?rid=166
http://thepiratebay.org/tor/3536729/1990_to_1995_OEM_Toyota_4Runner_Service_and_Wiring _Manuals
http://torrentportal.com/details/737089/1990+to+1995+OEM+Toyota+4Runner+Service+and+Wiring +Manuals.torrent

Sidney
Repairs TV's,VCR's,home/car audio out of my apartment
E-mail:sidneybek(at)yahoo.com
Dartmouth,Nova Scotia
Canada
1995 Toyota 4-Runner, 22R-E, G52 with 235 000 KM

Sorry about that, I used that site a few times and I knew it had the OBD II codes just by typing the code in after the website and a / .I figured it might have help also for OBD I since it wasn't called obd2-codes dot com. Anyways good luck. The codes can be translated however, if you have a 93 vehicle and the system is giving you a code 32 for example. That is the exact same thing as a P0302 which is a problem with the EGR system. And you would be able to look at the obd-codes site to see what to do to remedy the code.

Here is how to translate



2 digit code
example
43 is same as P0403 4 long flashes, 3 short flashes Throttle position sensor

3 digit code
example
105 is same as P1005 10 long flashes, 5 short flashes EGR solenoid

With the three digit code the first two digits are the first two of the 4 digit obd II codes, and the last digit is preceded by a 0 which is the 3 digit of the obd II code.