O2 sensors for long tube headers?

[superninja427]

Ok I drive a 91 Chevy ext. Cab 5.7 with a 5 speed. Im wondering what o2 sensors I need that will reach down to the reducers on my long tube headers and the cheapest ones I can buy for now. I would much appreciate the help guys.

 

[RPMGraphics]

you can buy o2 extensions.

 

[superninja427]

Casper electronics was telling me that it won't work right unless I convert it to 4 wire. I need two kits and each one is like 98 bucks...are they right? If so is there a cheaper way to put o2 sensors that work right on my truck?

 

[Hezsus]

91's only have one O2 sensor, on the drivers side. You could simply put it into a primary and be done with it. the collector is a much better option though, even for the an obd1 system. You can simply splice your current one longer. BUT, you must make the best connection possible, lots of flux and solder, and make the connection somewhere that it will see limited heat. I ran an O2 sensor spliced with a trailer wiring plug and it worked good for the time being but the sensors are very sensitive. Or you can buy one with longer wires if the one you have is screwed.

 

[skylark]

Actually you do need a 3 wire not a 4 wire sensor. The 3 or 4 wire sensors have a heater circuit in them. With your long tube headers the exhaust temperature will have dropped by the time the exhaust gets to the collector. This will make your factory 1 wire cooler than it is designed to be and it will be lazy in it's readings. When you install a heated O2 you won't have the problems of the sensor cooling off on deceleration and idle . You only need the one sensor though, not two.

 

[DRAGGIN95]

Actually you do need a 3 wire not a 4 wire sensor. The 3 or 4 wire sensors have a heater circuit in them. With your long tube headers the exhaust temperature will have dropped by the time the exhaust gets to the collector. This will make your factory 1 wire cooler than it is designed to be and it will be lazy in it's readings. When you install a heated O2 you won't have the problems of the sensor cooling off on deceleration and idle . You only need the one sensor though, not two.

Word!

 

[beast94]

Actually you do need a 3 wire not a 4 wire sensor. The 3 or 4 wire sensors have a heater circuit in them. With your long tube headers the exhaust temperature will have dropped by the time the exhaust gets to the collector. This will make your factory 1 wire cooler than it is designed to be and it will be lazy in it's readings. When you install a heated O2 you won't have the problems of the sensor cooling off on deceleration and idle . You only need the one sensor though, not two.

I fully agree. You will need a 3 wire O2 sensor. You should be able to pick a Bosch 3 wire from any parts store for around $60. You will have to splice the signal wires together, then you find a power source to supply the heater circuit. Im not sure what voltage you need, but my best guess would be a 5V source.

 

[superninja427]

Ok cool! That saves me a lot of money. So do I just go up to O'Reillys and tell them I need a 3 wire o2 sensor? Or is there something specific I need to ask for?

 

[Hezsus]

I was not aware that the pre 96 trucks didnt have a heated O2 sensor. Any heated O2 sensor should work, or one from a 96+ truck will too even though you wont need the 4th wire. I thought It was all 12v power for those though. either way it must be switched power, or on a toggle swithc but thats just alot of hassle. if you tap into the fuel pump relay or similar you wont have to add a relay or anything. Just make sure that you keep the wires away from the exhaust and such.

 

[beast94]

Yup, I believe it was in '93 when the 3 wires came on our trucks.