Previous Thread
Next Thread
Print Thread
#867461 02/10/04 12:08 AM
Joined: May 2003
Posts: 91
N
NJE96SE Offline OP
CEG\'er
OP Offline
CEG\'er
N
Joined: May 2003
Posts: 91
I have researched this, and I think I have it right - I am just looking for a confirmation from the knowledgeable people round here.

Downstream O2 sensors are used solely for monitoring the pre-cat efficiency, correct? The upstream sensors help coordinate the MAF with the fuel injectors by telling the PCM if the exhaust gas is rich/lean. The downstream sensors get a value for O2 concentration that the PCM uses to compare to the upstream sensor value and determine if the pre-cat is oxidizing the nasty stuff. Am I semi-correct here?

The reason I am curious is that I have a downstream sensor that is bad. Can I get a set of MIL eliminators (a pair is cheaper than a single O2 sensor) and plug those in and forget about downstream sensors for good? Do you need a functioning O2 sensor for the MIL eliminators to work?

Thanks in advance for you help.


06 Mustang GT - stock 96 SE V6 5spd Midnight Red - 15.9 @ 86.8 150K miles Mods: Bilstein struts, H&R springs, Borla Cat-Back, Brullen y-pipe, Gutted Precats, SVT UIM+LIM+TB, K&N FIPK, , DMD, Magnecor KV85
#867462 02/10/04 01:06 AM
Joined: Nov 2002
Posts: 851
B
Veteran CEG\'er
Offline
Veteran CEG\'er
B
Joined: Nov 2002
Posts: 851
The MIL eliminators depend on a functioning O2 sensor to work.

How did you determine that your downstream O2 sensor is bad?

#867463 02/10/04 01:18 AM
Joined: May 2003
Posts: 91
N
NJE96SE Offline OP
CEG\'er
OP Offline
CEG\'er
N
Joined: May 2003
Posts: 91
Originally posted by brianl703:

How did you determine that your downstream O2 sensor is bad?





CEL, went to Autozone.


06 Mustang GT - stock 96 SE V6 5spd Midnight Red - 15.9 @ 86.8 150K miles Mods: Bilstein struts, H&R springs, Borla Cat-Back, Brullen y-pipe, Gutted Precats, SVT UIM+LIM+TB, K&N FIPK, , DMD, Magnecor KV85
#867464 02/10/04 01:27 AM
Joined: Nov 2002
Posts: 851
B
Veteran CEG\'er
Offline
Veteran CEG\'er
B
Joined: Nov 2002
Posts: 851
Do you remember what the code was? If it was a P0420 or P0430 it's very likely not the downstream sensor that's the problem..


#867465 02/10/04 01:28 AM
Joined: Sep 2003
Posts: 2,725
H
Hard-core CEG\'er
Offline
Hard-core CEG\'er
H
Joined: Sep 2003
Posts: 2,725
Originally posted by NJE96SE:
I have researched this, and I think I have it right - I am just looking for a confirmation from the knowledgeable people round here.

Downstream O2 sensors are used solely for monitoring the pre-cat efficiency, correct? The upstream sensors help coordinate the MAF with the fuel injectors by telling the PCM if the exhaust gas is rich/lean. The downstream sensors get a value for O2 concentration that the PCM uses to compare to the upstream sensor value and determine if the pre-cat is oxidizing the nasty stuff. Am I semi-correct here?

The reason I am curious is that I have a downstream sensor that is bad. Can I get a set of MIL eliminators (a pair is cheaper than a single O2 sensor) and plug those in and forget about downstream sensors for good? Do you need a functioning O2 sensor for the MIL eliminators to work?

Thanks in advance for you help.





Mine went bad to, got it fixed Friday though. Also had the mechanic clean the MAF.

Did you get code PO171- to lean bank 1

That is what I had and he said the problem was the downstream O2 sensor.


#867466 02/10/04 01:54 AM
Joined: May 2003
Posts: 91
N
NJE96SE Offline OP
CEG\'er
OP Offline
CEG\'er
N
Joined: May 2003
Posts: 91
Originally posted by brianl703:
Do you remember what the code was? If it was a P0420 or P0430 it's very likely not the downstream sensor that's the problem..






If I remember right, it was P0141 (bank 1, sensor 2). I got it right after replacing my y-pipe. I think it may have been damaged during the install.


06 Mustang GT - stock 96 SE V6 5spd Midnight Red - 15.9 @ 86.8 150K miles Mods: Bilstein struts, H&R springs, Borla Cat-Back, Brullen y-pipe, Gutted Precats, SVT UIM+LIM+TB, K&N FIPK, , DMD, Magnecor KV85
#867467 02/10/04 02:11 AM
Joined: Nov 2002
Posts: 851
B
Veteran CEG\'er
Offline
Veteran CEG\'er
B
Joined: Nov 2002
Posts: 851
MIL eliminators will most likely not help then. They are designed to get rid of P0420/P0430 codes, and require a properly functioning downstream O2 sensor.


Moderated by  GTO Pete, Trapps_dup1 

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5