Toyota Tacoma P0420 cat or o2 sensor
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From: Marsh Monster on 16 Apr 2007 23:47 ====== ====== On Apr 16, 9:26�pm, jcaru <Jason.Car...(a)gmail.com> wrote: > Thanks for all the input. I have a good mechanic that will help the > truck pass emissions if you know what I mean. Say it is the front 02 > sensor. Will and after market Cat mess with my sensors at all. And > also how do I place the voltmeter on the sensor to test them??- Hide quoted text - > > - Show quoted text - ====== ====== your SECOND sentence..... yeah..i know what you mean...he's not a good mechanic, because a good mechanic would NEVER MAKE...a vehicle pass emisions. regardless..... here....more than you need to know, and more than you deserve because of your intent on be'n a stick in the mud about global warm'n... oh yeah..i know...there is NO global warm'n... sure...sure. .. http://www.smp-training.com/Counterman/O2Sensors/Pages/sensor01.html ~:~ MarshMonster ~slaps you side the head....sips his crownroyal.....hopes you come to yer senses....or sensors...or convertors~
From: al on 17 Apr 2007 21:32 On Apr 16, 10:26 pm, jcaru <Jason.Car...(a)gmail.com> wrote: > On Apr 16, 9:04 pm, "Paul." <paul.blomb...(a)cox.net> wrote: > > > > > > > Or, if you still have the old O2 sensor, take the new one and put it in > > front of the cat and put the old one back in the rear position. > > > It's cheap if you still have the old part. > > > Paul."al" <abuo...(a)msn.com> wrote in message > > >news:1176599284.186758.241300(a)n76g2000hsh.googlegroups.com... > > > > On Apr 14, 2:32 pm, "jcaru" <Jason.Car...(a)gmail.com> wrote: > > >> I have a 2000ToyotaTacomaTRD 3.4 liter with california emissions > > >> and 114,500 mile.P0420 catalyst efficiency below threshold (bank1) > > >> came up on OBDII scanner. My gas mileage seemed to have dropped about > > >> 3-4 miles per gallon since check engine light came on. I replaced the > > >> o2 sensor after the two cats a couple years back. From the reading I > > >> have done and people I've talked to it seems my cat maybe clogged. If > > >> I replace the cat with a High Flow cat (MagnaFlow) will it cause > > >> problems with my sensors. And also can I do anything about getting rid > > >> of one of the cats since I live in Pa and have no intentions of going > > >> to Cal. What is the best thing to do to fix this problem. Dealer price > > >> for front and rear cat are $940 and $1045 (not an option). > > > >> Thanks in advance for all replies. > > >> -Jason > > > > I'd definitely suspect the front O2 sensor before condemning the cat. > > > The drop in gas mileage is another strong indicator of a lazy O2 > > > sensor. The front O2 sensor monitors the oxygen content of the > > > exhaust gas in the manifold and should normally be switching rapidly > > > between about 200 millivolts and 800 mv as the computer rapidly > > > adjusts the fuel/air ratio to optimize the fuel mixture. If the cat > > > is working properly, the rear O2 sensor should output a fairly > > > constant voltage of about 450mv. The computer compares the switching > > > rate of the front O2 sensor to that of the rear O2 sensor. If the > > > switching rates are similiar, it sets theP0420code under the theory > > > that the exhaust gas coming out of the cat looks very similiar to > > > exhaust gas going into the cat and so the catalyst efficienct is below > > > normal. But if the front O2 sensor gets lazy and starts switching too > > > slowly, then theP0420code is set and the problem is the sensor and > > > not the cat. It is also possible that the front O2 sensor heater > > > circuit is malfunctioning which would cause the O2 sensor to not get > > > hot enough, especially at idle, to work properly. However, if that > > > were true, there is usually a separate code for that. Before spending > > > a ton of money on a cat, it would be very worthwhile to put the > > > vehicle on a scan tool and watch the operation of the O2 sensors and > > > observe that the O2 heaters are on. If you can't do that, investing > > > in a $50-75 OEM front O2 sensor first before opting for the $1000 fix > > > would seem to make good economic sense. Good luck. Al > > Thanks for all the input. I have a good mechanic that will help the > truck pass emissions if you know what I mean. Say it is the front 02 > sensor. Will and after market Cat mess with my sensors at all. And > also how do I place the voltmeter on the sensor to test them??- Hide quoted text - > > - Show quoted text - If you really need a cat, which I doubt, aftermarket catalytic converters are definitely the way to go. Federal law requires minimum standards for them. I believe, though I'm not sure, that they must be designed not only to adequetly reduce emissions but to last something like eight years. I don't recall the exact number of years. There's no compatability issue whatseover. Thanks for that very informative website with the primer on O2 sensors. If you want to test the sensor, a scan tool is really the only practical way to do it. The very informative website that another reply mentioned describes a voltmeter test but you'd have to tap into the wiring somehow and have a voltmeter with a fast response. It's also possible to bench test it with a blowtorch and a voltmeter but that's a bit of a Rube Goldberg approach. I presume the "good mechanic" can put the vehicle on his scan tool and not just conveniently look the other way during an emissions test.
From: Wes on 14 May 2007 19:55
The code you got does not mean the cat is clogged, it means that your OBDII is not reading the correct differences in gasses before and after the cats. One cause for this is leaks in the exhaust between the 02 sensors. Another cause is the platinum has worn off the ceramic matrix and the cat is no longer functioning properly according to OBDII standards. You can replace the cats with the Magnaflow cats and they will function as factory cats. I think that they are 50 state legal, but they may not pass CA because they are not factory (not because they do not function at factory specs, because they do). Inspect your exhaust and insure that the gaskets under the 02 sensors and between the cats are sealing. If there are no leaks, I would replace the cats with the Magnaflow cats. They are smaller than stock so a length of exhaust pipe is needed to fill in the gap. I got mine from hotexhaust for about $120 each and installation was about $50. Disregard retards pissing about global warming. When they explain how global warming on Mars has nothing to do with warming on earth, maybe then they will have something to say worth listening to. "jcaru" <Jason.Caruso(a)gmail.com> wrote in message news:1176575524.813977.243550(a)y80g2000hsf.googlegroups.com... >I have a 2000 Toyota Tacoma TRD 3.4 liter with california emissions > and 114,500 mile.P0420 catalyst efficiency below threshold (bank1) > came up on OBDII scanner. My gas mileage seemed to have dropped about > 3-4 miles per gallon since check engine light came on. I replaced the > o2 sensor after the two cats a couple years back. From the reading I > have done and people I've talked to it seems my cat maybe clogged. If > I replace the cat with a High Flow cat (MagnaFlow) will it cause > problems with my sensors. And also can I do anything about getting rid > of one of the cats since I live in Pa and have no intentions of going > to Cal. What is the best thing to do to fix this problem. Dealer price > for front and rear cat are $940 and $1045 (not an option). > > Thanks in advance for all replies. > -Jason > |