As you've guessed if it's varying between .5 and .8 (staying above .5 most or all of the time) the cat test will never start. If only the rear sensor is doing this ... while the front one is crossing the stoich point frequently ... either the cat is unloading a lot of stored HC's or the rear sensor is poisoned. A good cat can store enough HCs for this situation to last several minutes so you might want to defer your observations until after 10-15 min of steady freeway cruising. One of the cat's main jobs is to soak up the extra HC's that are produced during warm-up and during acceleration so maybe you just haven't looked at the numbers long enough yet. The actual cat test involves intentionally running rich for a short time to see if the cat actually does soak up the extra HC's, and then see how long it takes to dump them after the mixture goes lean/stoich again. Obviously that test can't be started unless the ECU believes that the cat is fairly empty of HC's.
----- Original Message ----- From: Bill Cardell To: Adam Wolf ; Miata Power List Sent: Monday, September 29, 2008 9:02 AM Subject: RE: OBDII readiness monitors... You need to look at how it varies. There are some good articles online about how to test by looking at cross-counts, the number of times the voltage crosses the stoich point at .45v. Typically easiest to do with a scope. Some good info here: http://mr2.com/TEXT/O2_Sensor.html Bill Cardell TurboDog's Dad www.flyinmiata.com www.fmwestfield.com Sales 1-800-359-6957 Tech 970-464-5600 Before you call, check out http://www.flyinmiata.com/FAQ/ ------------------------------------------------------------------------------ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Adam Wolf Sent: Monday, September 29, 2008 9:34 AM To: Miata Power List Subject: Re: OBDII readiness monitors... Ok, I got another question. Anyone know what the stock ECU likes the rear O2 sensor max value to be? Like, is there a high value that makes the ECU start looking to throw a bad cat code? I ask because I've logged some actual interesting data. Got my spiffy scanner all hooked up - http://www.amazon.com/Equus-3130-Diagnostic-Capability-Post-1996/dp/B000KID31K/ref=pd_bbs_sr_7?ie=UTF8&s=automotive&qid=1222702093&sr=8-7 and working. Far more data than the scangauge2. I now know that indeed all of my sensors are functional. On cruise, my rear o2 sensor reports between .03 (yeah, point zero three) and .2. Nice, low o2 readings. The reading tends to live between .03 and .08 most of the time. I see around .5 when I take off from a light, which seems fine to me. On the freeway at 70-80 mph, I see a range of .2 to .8, which seems high. Mostly it stays between .5 and .8.... my current theory: these high o2 readings are canceling any o2/cat tests that the ECU might be getting ready to do. Does this sound at all logical? thanks! Adam On Wed, Sep 24, 2008 at 11:13 AM, Adam Wolf <[EMAIL PROTECTED]> wrote: I've been working on this more (still haven't had the monitors change to set). I bought myself a very nice looking scan tool which should arrive today, so I'll undoubtedly have more questions/data on this problem. My new question: is it possible to have the EGR monitor set before the O2/cat monitors? I ask this specifically for the 96-97 ECUs. In my (limited) experience, the EGR is always the last monitor to set on this ecu. If I could get it to set before the o2/cat, all of my problems would be solved. I can pass with 2 unset monitors... thx! Adam On Thu, Sep 18, 2008 at 12:13 PM, Bill Cardell <[EMAIL PROTECTED]> wrote: Matt, email me a fax and I'll send you the factory manual pages on the drive cycle they want. Bill Cardell TurboDog's Dad www.flyinmiata.com www.fmwestfield.com orders 1-800-FLY-MX5S Before you call our tech line (970.464.5600) please check out the FAQ section of our website -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matt Bennett Sent: Thursday, September 18, 2008 11:31 AM To: Miata Power List Subject: Re: OBDII readiness monitors... OK, so what are the codes or procedure you need to do to get the readiness monitors? I've got some very basic OBDII tools (like an OBD2-serial port adapter) and I'd like to know how I can read them, and what I should be getting back. I've been looking all over for this information, but I can't find it. Matt On Wed, September 17, 2008 8:32 pm, Ray Ayala wrote: > The rear O2/cat monitors require somewhat specialized driving > conditions for performing their operability tests. Maybe you just > didn't get into the right 'zone' for long enough. They need > fully-warmed-up, steady-state, medium/low torque freeway cruising for about 30 minutes ... > in 'moderate' weather conditions. > ----- Original Message ----- > From: Adam Wolf > To: Miata Power List > Sent: Wednesday, September 17, 2008 10:23 AM > Subject: OBDII readiness monitors... > > > I'm having a devil of a time and I'm hoping the list can help me. > > Car: 97 w/ 99 motor. I normally run the Link, but had to swap the > stock ECU back in for emissions. I swapped ECUs a month ago for my > e-test that has a deadline of this friday. I just took the test and > failed in order to get the 1 year extension. > > So here's new stuff. Some of this has been added over the course of > the last month in an effort to get monitors to set. New front o2 > sensor. I recycled a 30k mile old o2 to replace my original 125k stock > rear o2 sensor that I thought might be "tired". new plug wires (it was > time), new-ish magnaflow cat (about 6 months since putting that in). > Car runs fine. Not as smooth as with the Link, but fine. > > It REFUSES to set the o2, cat, and EGR monitors! I've driven an > honest 500 miles in various conditions. I've performed a handful of > different "drive cycles" I found on Miatanet including one that > claimed to be for a 97 specifically. Still nothin. I can have 2 > monitors not ready in Albuquerque, but not 3. 3 is fail. > > Does anyone have any ideas? I never had this problem before. On a > normal commute to work, this car would run and pass all tests in 2 > days (4 cold-start drives). But 2 years later after running the Link, > there's no joy. I just need to get ONE more test to run. I'm going crazy. > > thanks, > > Adam > > > > ---------------------------------------------------------------------- > -------- > > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower ------------------------------------------------------------------------------ _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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