VFAQ o2 sensor bypass problem

[ShortysTRM]

We finally got a resistor big enough to join the 2 black wires to the o2 sensor. They are supposedly the wires to the heating element and need an "around 12 ohm" and "at least 12 watt" reasistor, so we got a 15 ohm/25 watt resistor. We plugged in the new harness and started the car and let it idle. After a minute or two, it got pretty warm. After like 6 or 7 minutes, it was too hot to hold for more than a second or so, and soon began smoking. We had the resistor wrapped in electrical tape, and I am thinking that may have inhibited the heat dissipating properties of the ceramic around the resistor, but we don't wanna try anything until we get a few opinions, so if you can help at all, please repond to this as soon as you read it. Thank you in advance for any help .

 

[CODE4]

We finally got a resistor big enough to join the 2 black wires to the o2 sensor. They are supposedly the wires to the heating element and need an "around 12 ohm" and "at least 12 watt" reasistor, so we got a 15 ohm/25 watt resistor. We plugged in the new harness and started the car and let it idle. After a minute or two, it got pretty warm. After like 6 or 7 minutes, it was too hot to hold for more than a second or so, and soon began smoking. We had the resistor wrapped in electrical tape, and I am thinking that may have inhibited the heat dissipating properties of the ceramic around the resistor, but we don't wanna try anything until we get a few opinions, so if you can help at all, please repond to this as soon as you read it. Thank you in advance for any help .

I would suggest mounting the resistor (if it has screw tabs) to a metal plate, or to a project box lid (the kind found at radio shack) for further heat disapating action. Electrical tape will insulate the heat exchange from happening on the heat sink if you wrap the resistor.

 

[ShortysTRM]

thanks for the suggestions. I may try that, but we're still thinking things over. I would like to know what other people who have tried this did to get it to work.

 

[ShortysTRM]

bump.

 

[kpt4321]

Don't bump at all, and especially not after 30 minutes.

Surface area is your friend, give it a heat sink.

 

[ShortysTRM]

for one thing, I bumped after a week. Second, you're the second person to say that, but no one says how to attach a heat sink to it. It is a very chalk-like ceramic resistor and a heat sink is usually aluminum (or another metal)...so how would I attch the two without actually reducing the efficiency of the heat sink or the ceramic by putting an adhesive between the two surfaces. And after that's all said and done, where the hell can we mount it? You can't exactly just mount this thing in your grill.

 

[1 fast eclipse]

I wrapped mine with exhaust heat wrap and it has holes on the sides for it to air out had it for a year and a half and works great i have it sitting under my seat. Tried electrical tape at first and drove the car to NY and the thing melted on me when i got back home in NJ. Hope this helps you out.

Leo

 

[ShortysTRM]

Wow, thanks a lot man. That it is exactly what I needed was advice from someone who has done it and succeded (and failed, too ). I guess we will probably try that soon. Can you just take a Mitsu to like autozone and have them clear the code? I don't know shite about a datalogger, as I don't even drive a Mitsu. Once again, thanks, man.

 

[1 fast eclipse]

you can clear the code by taking out the battery for 30sec-1min considering that you fixed the problem.

Leo

 

[kooka]

where did you get the 15 ohm/25 watt resistor?

thanks.

 

[TD05HTalon]

use the thermal paste to attach the heatsink. You can probably get it at Radio Shack or a computer store - it's the same stuff you use to attach a heatsink to your cpu. It transfers heat perfectly.

 

[ShortysTRM]

thanks again guys...We got it at Electronic Supply in Huntington, WV for ~$2.10.