More 02 help Please!
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Joined: Mar 2010
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From: Bushnell ,Fl
More 02 help Please!
Ok . Let me tell you what I have and what I have done so far as I need help on getting it right . I have a 97 4x4 5.9 with headers duel exhaust no cat . I did notice that their are two 02 sensors both on pipe coming from passenger side second sensor being about 1 1/2 ta 2 feet from front one. I bought new sensor for the down stream (back) hope that was right lingo ... and put it in using the directions I found on here for the de fouler install. the light came back on saying bad 02 So should I replace the other one? It just seems wrong them both being on same side? The sensors looks the same so should I look for a before cat sensor or what... And I just screw it in the place of the other one not using any de fouler on front one right?Thanks for the help!
Last edited by Jackstand123; May 1, 2010 at 02:55 PM.
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Joined: Jan 2008
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From: Sioux Falls, SD
The first sensor is probably the "pre-cat" or upstream sensor. It helps determine your air/fuel ratio by feeding the PCM data on your exhaust.
Have your codes checked, or post the code here. Maybe your first sensor is bad.
The non-fouler trick doesn't work for everyone. There are O2 sims available here to fool your 2nd sensor, but they aren't cheap.
Have your codes checked, or post the code here. Maybe your first sensor is bad.
The non-fouler trick doesn't work for everyone. There are O2 sims available here to fool your 2nd sensor, but they aren't cheap.
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Joined: Jul 2006
Posts: 12,204
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From: Gainesville, Ga.
here's some basic info you should know.
like jason said, the front (upstream) cat sniffs the exhaust stream and provides critical feedback to your pcm, which uses the data to adjust the richness of the fuel flow through the injectors. the rear (downstream) cat sniffs the exhaust after the cat and sends that data to the pcm. the pcm compares the 2 readings to determine that the cat is working properly to remove emissions.
all our non-california trucks came from the factory with only one combined exhaust pipe and one cat and two O2 sensors. this makes it more difficult to install true dual exhausts. the california versions had dual exhausts, dual cats, and 4 O2 sensors, so this setup is a natural for duals. the others are not.
what does this mean to you. having both 02 sensors in only one side is not exactly right. it means you are adjusting mix to both sides of the engine based on the feedback from just one side. is this the right way to do it ? no. is this bad ? no not really.
what can you do. first - post the codes you've got. there's a lot of codes associated with O2, and some refer to the front and some to the rear. to compensate for no cat, you can try the non-fouler on the downstream, or hang it out of the exhaust, or get an electronic simulator.
if you wanted to really fix it right, you could put a H or X pipe between the two sides, and place your front O2 in the crossover. if your engine is not running right, you might want to do this. if its running ok, it may not be necessary.
post your codes....
like jason said, the front (upstream) cat sniffs the exhaust stream and provides critical feedback to your pcm, which uses the data to adjust the richness of the fuel flow through the injectors. the rear (downstream) cat sniffs the exhaust after the cat and sends that data to the pcm. the pcm compares the 2 readings to determine that the cat is working properly to remove emissions.
all our non-california trucks came from the factory with only one combined exhaust pipe and one cat and two O2 sensors. this makes it more difficult to install true dual exhausts. the california versions had dual exhausts, dual cats, and 4 O2 sensors, so this setup is a natural for duals. the others are not.
what does this mean to you. having both 02 sensors in only one side is not exactly right. it means you are adjusting mix to both sides of the engine based on the feedback from just one side. is this the right way to do it ? no. is this bad ? no not really.
what can you do. first - post the codes you've got. there's a lot of codes associated with O2, and some refer to the front and some to the rear. to compensate for no cat, you can try the non-fouler on the downstream, or hang it out of the exhaust, or get an electronic simulator.
if you wanted to really fix it right, you could put a H or X pipe between the two sides, and place your front O2 in the crossover. if your engine is not running right, you might want to do this. if its running ok, it may not be necessary.
post your codes....