o2 simulator question

[servidjo]

i installed the atr downpipe on my car and it didnt have spots for my o2 sensors that came after the precats and monitored their functionability. so i just tied them up, and of course, the check engine light came on. it was the code for the 2 precats malfunctioning. so i was thinking about welding spots for the sensors, but if i eliminate the precats in the future, id be back a square one. so i am looking into o2 simulators. i searched and found 2 places, one at mvp motorsports, and the other at casper electronics. does anyone have any input or experience with either of these and which one do you recommend?

[jeff97vr4]

I've got the Casper's simulators. You still have to wire an 82 ohm 5 watt resistor into the harness to simulate the O2 heater. The error code I got was for the heaters, go figure. But with the simulators and the resisitor there are no error codes. You can use a range of reistances, smaller resistance will heat up more and will have to be higher wattage. I'm not sure how high you can go and have less heating, this worked and I didn't want to mess around any more.

Jeff

[slava]

jeff, how exatly simulator is pluged in?

[jeff97vr4]

Originally posted by slava
jeff, how exatly simulator is pluged in?

The simulator is wired into the O2 Sensor wiring. The O2 is cut out and just the connector and wiring is used. I'd rather not cut into the factory harness just I case ever wanted to switch back to stock. The 12V for the heater powers the sim, the heater ground is sim ground, and the sim output connects to the sensor signal back to the ECU. The resistor is across the 12V heater lead and heater ground. the sim's are about 2x0.75x0.5 in in size. I'd contact Casper's directly if you're interested in buying, his prices was better than dealers when I bought them.

I would rather not drive with the CEL on, a real problem could develop the the CEL could alert me about before it caused damage. Just my personal belief.

Hope this answers your question.

Jeff

[slava]

Jeff,
i was plaing with the 02 today. I connected the voltmeter to the after cat O2 sensor and getting reading of 0.35v only. I did not change when i started the car and it warmed up. I did not drive the car yes so can not tell if reading will change.
Is there any chance you could check the voltage from SIM? I think it is constant and can be checked as soon as car as started or ignition on.
Thanks a lot.

[Dan's VR-4]

Jeff,

I'm getting the same CEL for the heater. Are you saying that you could have simply wired in a 82 ohm 5 watt resistor and that would have fixed the problem? If so, please post some details

Thanks,
dan

[jeff97vr4]

slava,

My car is down right now, the trans is out again in case you haven't seen the RPS c-c thread. I have not measured the output of the sim, but I do recall being told by Casper's that the sim varies the output voltage. I'll try and check it out, maybe tomorrow, and I'll post the results.

0.35V out of your O2 sounds like the ECM default value when the car is first started. If the value doesn't change, there is something wrong with the sensor or where you are measuring the voltage. The blue wire from the sensor harness or the white wire from the ECM harness to chassis ground is where to measure. Are your precats MIA?

Dan's VR-4,

An 82 ohm 5 watt resistor will trick the ECM. The two black wires of the O2 harness are the correct wires for the heater. On the ECM side, the red wire is +12v. There are two black wires, one is chassis ground for the O2 output and the other goes to the ECM to monitor current, this is the one to use if you are going to wire on the harness side. I'd suggest using the sensor wiring just in case you ever want to switch back. Solder the resistor to the two black wires (if you use the O2 sensor wires), wrap in electrical tape, and you're done. I think I paid about $1-2 for a package of two resistors. You do need the 5 watt power rating to avoid burning the resistor out and possibly starting a fire.

Hope this helps.

Jeff

[slava]

Looks like the before and after cat O2 sensors are not the same. The precat is the reduction type Cat and it reduces the amount of NO and NO2. It make the second sensor to watch for NO/NO2 and not for O2 level. It is consistent with sensor output . i drove the car on the highway and acceleration / decceleration and the sensor reading did not change 0.35-0.37V. There are not precats there not NO/NO2 reduction. I also measure the current going through the sensor and it was ~0.7A.
Now i just need to make stabilzer circute to feed the ECU with 0.45-0.5V and be able to produce 1A. Then will see.
If i disconnect the O2 the CEL come on right away. Make sense.
that is it.

[slava]

Jeff,
where did you buy 5watt resistors?
I can't find on radioshack.com

[Dan's VR-4]

Originally posted by jeff97vr4
Dan's VR-4,

An 82 ohm 5 watt resistor will trick the ECM. The two black wires of the O2 harness are the correct wires for the heater. On the ECM side, the red wire is +12v. There are two black wires, one is chassis ground for the O2 output and the other goes to the ECM to monitor current, this is the one to use if you are going to wire on the harness side. I'd suggest using the sensor wiring just in case you ever want to switch back. Solder the resistor to the two black wires (if you use the O2 sensor wires), wrap in electrical tape, and you're done. I think I paid about $1-2 for a package of two resistors. You do need the 5 watt power rating to avoid burning the resistor out and possibly starting a fire.

Hope this helps.

Jeff

Jeff,

That helps a bunch. As soon as my knee gets better I'll get under there and set that up. Thanks

dan