02 Sims ???
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
Likes: 2
From: Simpsonville SC
02 Sims ???
I have them on my rear O2's cause of cat delete. My check engine light came on and said its the back passenger side O2 sensor. Does the O2 sims go bad? Only had for a little over a year and less then 4,000 miles.
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
02 sims are notorious for being unreliable/short-lived,
I went thru 3 sets in 3 years...now I have the rear 02s shut off in the PCM program and no longer need the sims.
I went thru 3 sets in 3 years...now I have the rear 02s shut off in the PCM program and no longer need the sims.
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
Likes: 2
From: Simpsonville SC
I figured I can do that with a tune. But Im installing a Cam a few months from now and I didnt wont to tune my car twice. Kinda expensive for 3 months. Will it hurt my car any if I dont get that rear O2sim replaced? Thanks
P.S. Thats a Bad Yellow Vette You Have
P.S. Thats a Bad Yellow Vette You Have
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
No problem in hurting the car or performance.
The ONLY function of the sims is to keep the CE light out. If you don't have an emissions test to pass in the next few months, don't waste your money on another set, just reset the code when the CE light comes back on.
The ONLY function of the sims is to keep the CE light out. If you don't have an emissions test to pass in the next few months, don't waste your money on another set, just reset the code when the CE light comes back on.
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
Likes: 2
From: Simpsonville SC
Weird thing happen yesterday. Went in and got my hair cut came out and the check engine light was out. Hmmm oh well. I guess the plug is loose or something. Just thought Id tell yea
Hmmm oh well. I guess the plug is loose or something. Just thought Id tell yea
Racer
Joined: Dec 2006
Posts: 272
Likes: 3
From: South Louisiana
It could be the O2 itself as most Mils need a functioning O2 to work correctly.
A brief explination of MOST Mils using round numbers for simplicity.
A good rear O2 with the Cat in place sends a 400Ma signal to the ECM to say the cat is working properly.
(300-500 is the good range)
Now remove the Cat and the rear O2 reads rich and the signal jumps to 600Ma.
All Mils do is add a resistor in line that cuts the O2 signal by 200Ma.
So you add the Mil to this 600Ma signal and it cuts 200Ma off and bingo, your right back at 400Ma and everything is fine.
Now, if the O2 actually goes bad and the signal from it drops to 400Ma and the mil cuts another 200Ma you are now down to a 200Ma signal to the ECM and BAM, CEL is on.
Bottom line is that with plug and play (Inline) Mils the O2 sensor must be good.
They do make electronic Mils that always send 400Ma, but they are a little more expensive, harder to find and the O2 actually doesn't even plug into them.
So it sounds like your O2 could be headed south. But, the Mils could be bad also.
Easy way to tell which, Switch the mils from side to side if possible. If the Code switches to the drivers side it is the Mil, if it stays it is the O2
A brief explination of MOST Mils using round numbers for simplicity.
A good rear O2 with the Cat in place sends a 400Ma signal to the ECM to say the cat is working properly.
(300-500 is the good range)
Now remove the Cat and the rear O2 reads rich and the signal jumps to 600Ma.
All Mils do is add a resistor in line that cuts the O2 signal by 200Ma.
So you add the Mil to this 600Ma signal and it cuts 200Ma off and bingo, your right back at 400Ma and everything is fine.
Now, if the O2 actually goes bad and the signal from it drops to 400Ma and the mil cuts another 200Ma you are now down to a 200Ma signal to the ECM and BAM, CEL is on.
Bottom line is that with plug and play (Inline) Mils the O2 sensor must be good.
They do make electronic Mils that always send 400Ma, but they are a little more expensive, harder to find and the O2 actually doesn't even plug into them.
So it sounds like your O2 could be headed south. But, the Mils could be bad also.
Easy way to tell which, Switch the mils from side to side if possible. If the Code switches to the drivers side it is the Mil, if it stays it is the O2
