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Downstream O2 eliminators #4603059
12/13/17 11:38 PM
12/13/17 11:38 PM
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Alex_V Offline OP
Alex_V  Offline OP
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Aside from the emissions/legality concern, will a "dummy" device designed to do away with downstream oxygen sensors (used in a compatible application) affect performance or engine longevity any calculable amount?


To quote a friend, "Synthetics, man."

'85 GMC C3500, 454, 132K
'82 Mercedes 300CD, OM617 turbo, 173K (totaled 2018, in rehab)
'85 Mercedes 300TD, OM617 turbo, 217K (wife's)
'67 Suburban, 350, 331K
Re: Downstream O2 eliminators [Re: Alex_V] #4603062
12/13/17 11:45 PM
12/13/17 11:45 PM
Joined: Jun 2005
Posts: 11,620
Santa Barbara, CA
bdcardinal Offline
bdcardinal  Offline
Joined: Jun 2005
Posts: 11,620
Santa Barbara, CA
Nope. Their only purpose is to monitor catalyst efficiency. You can stack spark plug non foulers and get the same result for less.


2014 Ford Mustang GT Track Pack
1995 Ford Mustang GT

Ford/Mazda Parts Counter
NRA Benefactor Member
Opinions expressed are my own.
Re: Downstream O2 eliminators [Re: Alex_V] #4603070
12/14/17 12:02 AM
12/14/17 12:02 AM
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Alex_V Offline OP
Alex_V  Offline OP
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
I'm aware of the non-fouler trick. In this case, the moron that replaced the engine in a new customer's '02 F150 (4.2L V6) a few months ago cut out the cats and the downstream O2's, replacing them with several feet of flex pipe clamped at each end. (Yee haw, welcome to Kentucky.) The expense of new cats is out of the question for him (he could barely scrape together the money for me to do intake gaskets) and with the downstream sensors completely gone, a set of eliminators is half the cost of two new sensors that are just going to get non-foulers put on them to keep the CEL off. However, the local exhaust shop (going to put some proper pipe in place of the flex for a good price) won't do the pipes unless they put sensors in them, claiming it'll ruin the engine shortly if they aren't there.

I just wanted to know if I was under the wrong impression about the function of the downstream sensors or not. It appears I was correct.


To quote a friend, "Synthetics, man."

'85 GMC C3500, 454, 132K
'82 Mercedes 300CD, OM617 turbo, 173K (totaled 2018, in rehab)
'85 Mercedes 300TD, OM617 turbo, 217K (wife's)
'67 Suburban, 350, 331K
Re: Downstream O2 eliminators [Re: Alex_V] #4603185
12/14/17 07:08 AM
12/14/17 07:08 AM
Joined: Nov 2009
Posts: 1,067
Warner Robins, GA
nwjones18 Offline
nwjones18  Offline
Joined: Nov 2009
Posts: 1,067
Warner Robins, GA
Yeah there is no danger in running the downstream eliminators, and they work very well IMO. Best prices I've found are on Ebay.


1988 F-150. 4.9 I6 247k. 10w-40 Castrol Syn-blend ACDelco UPF2.
2005 Cadillac STS N* 108k. 5w-30 Castrol Magnatec ACDelco Classic PF61
Re: Downstream O2 eliminators [Re: Alex_V] #4603235
12/14/17 08:23 AM
12/14/17 08:23 AM
Joined: Oct 2012
Posts: 2,478
Staten Island, NY
michaelluscher Offline
michaelluscher  Offline
Joined: Oct 2012
Posts: 2,478
Staten Island, NY
I believe there's a small set of cars (mid 90s Chrysler's) that actually use the downstream oxygen sensor to work in tandem with the upstream

Otherwise, eliminate/space away


'06 Toyota Camry SE V6 3MZ-FE 100k
'01 Mercury Villager Estate VG33E 52k
'06 Ford Taurus SE Vulcan 60k
'13 Chrysler 300 3.6 Pentastar 230k
Re: Downstream O2 eliminators [Re: Alex_V] #4603294
12/14/17 09:19 AM
12/14/17 09:19 AM
Joined: Jul 2002
Posts: 4,552
KY
MCompact Offline
MCompact  Offline
Joined: Jul 2002
Posts: 4,552
KY
In my experience, the only people that say that 02 eliminators are bad are the ones who want to sell you a new cat...


Mine:
2014 M235i
2009 Cooper Clubman
1999 Wrangler Sahara
1995 318ti Club Sport

Wife's:
2015 X1 xDrive28i


Son's
2009 328i

Buy what makes you smile...
Re: Downstream O2 eliminators [Re: Alex_V] #4603460
12/14/17 11:46 AM
12/14/17 11:46 AM
Joined: May 2016
Posts: 719
Canada
i_hate_autofraud Offline
i_hate_autofraud  Offline
Joined: May 2016
Posts: 719
Canada


Downstream O2 sensors are part of a second closed feedback loop for the engine module,
they monitor if the up stream O2 are OK and if the Cats are functioning correctly.

You can bet OEMs have lots of code running to validate all O2 since they are critical
to smog controls! The O2 signals change as an engine starts cold and runs til hot and
beyond, the system checks they are outputting correctly under all conditions.

So fake O2s won't cut it.

Re: Downstream O2 eliminators [Re: i_hate_autofraud] #4603537
12/14/17 01:23 PM
12/14/17 01:23 PM
Joined: Nov 2004
Posts: 7,806
Texas
GMBoy Offline
GMBoy  Offline
Joined: Nov 2004
Posts: 7,806
Texas
Originally Posted By: i_hate_autofraud


Downstream O2 sensors are part of a second closed feedback loop for the engine module,
they monitor if the up stream O2 are OK and if the Cats are functioning correctly.

You can bet OEMs have lots of code running to validate all O2 since they are critical
to smog controls! The O2 signals change as an engine starts cold and runs til hot and
beyond, the system checks they are outputting correctly under all conditions.

So fake O2s won't cut it.


Fake 02's and Stacked Non-foulers do, in fact work. I've used both probably 100 times with complete success.

The post cat 02's are just an emission monitor for the convertor's performance. Most cars, true not all, but atleast 80% do not use the post 02 data for anything else.

Re: Downstream O2 eliminators [Re: Alex_V] #4603559
12/14/17 02:19 PM
12/14/17 02:19 PM
Joined: Jun 2005
Posts: 11,620
Santa Barbara, CA
bdcardinal Offline
bdcardinal  Offline
Joined: Jun 2005
Posts: 11,620
Santa Barbara, CA
If you want to get technical, Ford calls the rear O2s "cat monitors" in a lot of publications.


2014 Ford Mustang GT Track Pack
1995 Ford Mustang GT

Ford/Mazda Parts Counter
NRA Benefactor Member
Opinions expressed are my own.
Re: Downstream O2 eliminators [Re: bdcardinal] #4603818
12/14/17 07:35 PM
12/14/17 07:35 PM
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Alex_V Offline OP
Alex_V  Offline OP
Joined: Apr 2016
Posts: 1,198
Campbellsville, KY
Originally Posted By: bdcardinal
If you want to get technical, Ford calls the rear O2s "cat monitors" in a lot of publications.


Ha, nice. laugh


To quote a friend, "Synthetics, man."

'85 GMC C3500, 454, 132K
'82 Mercedes 300CD, OM617 turbo, 173K (totaled 2018, in rehab)
'85 Mercedes 300TD, OM617 turbo, 217K (wife's)
'67 Suburban, 350, 331K
Re: Downstream O2 eliminators [Re: Alex_V] #4603864
12/14/17 08:16 PM
12/14/17 08:16 PM
Joined: Aug 2006
Posts: 9,887
Central Washington
Colt45ws Offline
Colt45ws  Offline
Joined: Aug 2006
Posts: 9,887
Central Washington
Yeah, since this is a Ford I actually have the Ford OBD manual for '01 and '04 that goes in depth about how all the various emission systems work. The rear O2 is just for cat monitoring.


-Colton
2002 Ford Crown Vic PI 207k, Ex-Kootenai County, ID Unit #42
Down for engine swap
2003 Ford Crown Vic PI 75k
Castrol EDGE HM 5W30, Fram XG2
Re: Downstream O2 eliminators [Re: Alex_V] #4603909
12/14/17 08:58 PM
12/14/17 08:58 PM
Joined: May 2012
Posts: 5,681
Fort Lauderdale, FL
DoubleWasp Offline
DoubleWasp  Offline
Joined: May 2012
Posts: 5,681
Fort Lauderdale, FL
I've used plenty of the non-foulers to great success. Some need a bigger stack than others (Chrysler), but they will work.


07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio

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