Emissions and Error Codes

[S0crates]

It's been a long, hard weekend of wrenching on the car, and it's not working. Here's what happened, please, please help me if you can!

I picked up a 1995 240SX Base about 6 months ago. The check engine light was lit, so when I got home, I checked the ECU for error codes and got 10-5. Looking this up in the manual revealed the culprit to be the EGR and Canister Control Solenoid. I didn't bother with trying to fix it until this weekend. I disassembled the intake, fuel rail and intake-manifold to get to the culprit. After replacing the Solenoid, I then removed the EGR Tube, EGRC-BPT and EGR Valve, blocked off the Exhaust Manifold and Intake Manifold ports for the EGR Tube, and blocked off the vacuum hose going from the Solenoid to the EGRC-BPT. However, I kept the carbon canister, which is why I replaced the solenoid in the first place. I also replaced the air filter with a Cone-Type.

After reassembling everything, I got the check engine light. 3-2, 3-3, 3-4. The manual says these mean, EGR Function, Front Oxygen Sensor and Knock Sensor! So now I am much worse off. The next thing to note is that I did not try to trick the EGR Temp Sensor with the resistor like some have done, that explains the first error code. I figured that after I replaced the Solenoid, the ECU would assume EGR was working, and change the fuel/air ratio because it thinks some of the air is exhaust. So the car ran lean, which caused the engine to knock. This also explains the Oxygen sensor.

So, next I assumed if I simply clear the ECU and unplug the power adapter to the Solenoid, I would be back to only having error code 10-5. Well that didn't work. Because now I have error codes 3-3, 3-4 and 10-5!!!! (Front Oxygen Sensor, Knock Sensor and Solenoid valve)

I would rather not disassemble things again, but I need this working. What went wrong? If the Solenoid is unplugged, wouldn't the ECU assume no exhaust gases are making their way back to the intake, and so, the air/fuel ratio would be normal? What else could cause the Oxygen sensor and the Knock sensors to be lit?

I replaced the air filter with a cone-type, and I moved the air temperature sensor to the new cone's bracket. Could I have foiled it up and caused this?

Thank you guys!

[S0crates]

I just read the manual more carefully. The ECU sends a signal when it wants the Solenoid to close the valve to the EGR and Carbon Canister. That means they were permanently stuck open before! Hmm...

What can I do now?

[ob1]

I had that same fault code for years and finally fixed it with a solenoid. For 3yrs I drove around with a relay in place of the egr solenoid. I used terminal 85 & 86 of the relay and since the solenoid is a coil anyway you are just putting the relay in its place. the ecu turns this coil on at 2000 rpm that will take care or the 105 code. code 33 just change o2 sensor make sure all connections are good.

ob1 at 8:38 PM 8/21/2007
Modified by ob1 at 1:35 PM 8/22/2007