I have a 1995 Toyota Avalon XL that I bought used 2 years ago. Has 125K miles. Runs good, but check engine light has been on for a while. Occasional hard start, though not when engine's cold and I prime system by turning key to "on" (ACC) for a few secs.
Problem is: this model yr. is one yr. before OBDII. It has 2 diagnostic ports: on passenger side of engine and underneath steering column. Testing requires placing jumper wire between T1 and E1 on either port. Have tried this on both ports but have not been able to activate diagnostic blinking of check engine light. So....no diagnostics.
Things I have recently done: replaced front O2 sensor, cam shaft pos sensor, pcv valve. cleaned MAF sensor. Not sure what I should do next.
I had changed plugs last yr. and there is now some carbon fouling, so car may be running rich. What would you suggest I do next: replace other 2 O2 sensors, or replace MAF sensor, or something else?
Thanks, Eric in San Antonio
diagnostic codes are helpful but not 100% necessary. The older goats like scotty used to diagnose cars by sound. They would rev the engine some and slap the rear end to hear for what she needs. A car that old is due for some vacuum leaks around intake manifold and various vacuum lines. Some of those cracks and crevices in the rubber don't show themselves until after the car is warmed up some. The V6s to S4 engines give that much more room for error since the head is split across the block. A replacement part here or there might not help much
Thanks for reply. Vac lines appear ok but will check after warming engine. Be careful 'bout slappin' them rear ends: you could get sued!
You can buy a plug adapter to get codes. Or short the pins and it should blink the codes out with the check engine light. You can try and autos parts store that has the adapter get them to read the codes. I’ve gotten bad parts from auto stores. Especially some of the cheap sensors they make in china. Blindly swapping parts can cause more problems. See if your holding fuel pressure. If your aboe to turn the key on and off for a few seconds and then start ok sounds like your fuel pump might be going bad. Hit the schrader valve on the fuel rail after its been sitting. If it doesn’t squirt fuel your losing pressure on the fuel line.
his post says he tried shorting pins
Yea, I know. And I said it should.
Found this on another site.
Before proceeding, make sure the:
CHECK ENGINE light circuit is functional.
It should be ON when the ignition switch is ON with the engine stopped.
Battery voltage is above 11 volts.
Throttle valve is fully closed. (foot of the gas)
Accessory switches (A/C, etc.) are OFF.
Engine is at normal operating temperature (if possible).
Turn ignition switch to ON position.
Do not start the engine.
Place a jumper wire(paper clip) across TEl and El terminals in engine check connector.
Count number of flashes from CHECK ENGINE light.
If system is operating normally (with no detected faults), the CHECK ENGINE light will blink continuously
and evenly about 2 times a second.
Otherwise, the light will blink a number of times equal to the trouble code
Thanks Thumpy for reply. don't know what schrader valve is but will find out. Will look for adaptor to read codes, if such an animal truly exists. Followed procedure exactly as you outline, but no blinks; light stays on. Tried it 3-4 times using both ports, but nothing.
Schrader valve is the valve you use to put air in your tires. You should have one similar as a test port on your fuel rail near the throttle body. Just follow the fuel line you’ll find it. Some models didn’t have that type of valve so if you don’t see it this is for a corolla but can use same procedure get ya there. If you don’t have four cyl lemme know I’ll find ya a video with V6