When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So - just the O2 Heater test completed? Check your "distance since last OBDII clear" with the scanner. I suspect if it's showing 0 miles that you ECU might be clearing each cycle - check your room fuse.
I have been told that there are a few things that have to happen to get the ready condition. The catalytic converter has to reach a certain temperature. You then have to drive for an unknown amount of time while maintaining that temperature.
Most shops will tell you to drive 'x' number of miles at highway speed, typically 30-40 miles in one trip. It is my understanding that the colder the ambient temperature, the longer it takes to get to the temperature the computer wants.
If your many miles over several months did not include a long continuous stretch, that could be your problem. Then again, this might all be bullshit, it's just what I have been told.
Also my understanding is that the EGR system on the Miata is only engaged under conditions that a Miata rarely encounters, so it can take a long time to register ready. It only feeds off of #4 and is essentially useless on a miata but necessary for emissions regs.
Hm, that doesn't match my understanding of EGR at all. It engages at part throttle cruising situations, and what it does is replace some of the normal atmospheric nix (which is roughly 80% nitrogen, N2) in the intake charge with inert gasses from the combustion products (H2O and CO2 mostly). Those other gasses absorb some of the excess combustion heat, meaning you get less NOx in the exhaust.
Feeding off #4 only isn't an issue because it's not intended to treat the existing exhaust gas, it's just used to displace N2. It doesn't hurt power because it's only engaged during part throttle conditions, so you just open the throttle a bit more to get your desired power level back. OEMs actually engage this as much as they can, because opening the throttle like that means lower pumping losses and better fuel efficiency. EGR is worth 1-2 mpg.
My experience (NB1, not NB2) is that as long as everything is working correctly, it's possible to go from a code reset to ready-for-smog in a single 15 minute drive. You need to start it from cold, not spend a huge amount of time idling, spend a bit of time at part throttle cruise (50-ish mph) operation, and do a couple other things. The usual sticking point is the EVAP system, because that can only be tested when the tank is between 1/4 and 3/4 full. IME, if the car refuses to set the monitors as ready, that usually means there's something not working properly, but it hasn't gotten to the point of setting a code yet.
In the factory service manual, there is a published set of drive cycles designed to satisfy all of the readiness tests after a repair. The relevant pages are below.
Obviously, the readiness tests are designed to be able to be satisfied in normal driving as well, this is merely a shortcut intended for repair shops to use in order to quickly get the system into a "ready" state.
There can be codes thrown before setting a MIL/check engine. There's lots of example drive cycles out there, but I remember trying to get my 96 to set readiness.. my commute was 50 miles, all interstate, and it would not set after two weeks. It needed a 40mph cruise to keep it in closed loop, below 4000rpm. A quick drive on a highway and through some neighborhoods and it finally set.
Trying to get my nb2 thru emissions. We are a plug in state and if all is well and no cels and the obd2 diagnostic tests are complete, you pass. I have 3 tests that haven't completed yet. Oxygen sensor monitor, catalyst monitor and egr system. It has been months and many miles of varying conditions and no go. Any advice?
I know it's generally a ridiculous idea to try and diagnose emission/engine management related issues without actually seeing a car, but...
Those three conditions you mention may be indicating an exhaust leak that may ve disrupting exhaust flow and/or diluting the said exhaust gases.
I would even go as far as checking backpressure.
Also, if you have access to a scope, graph your upstream O2 sensor at idle. If you see any hash/noise at the top (crest) of your waves/oscillations, that indicates carbon buildup on your intake valves. (Hash at the bottom (trough) indicates a bad ground).
Carbon buildup on the valves will affect both the O2 sensors and - in some cases - EGR frlow...
Please keep my disclaimer in the beginning of this post in mind.
Will check for exhaust leaks etc. Running an artech manifold to 3" dp on back. 2560r has the wastegate disconnected. Egr valve is plugged in but not connected to a crossover pipe.
Interesting. That was going to be my plan to pass the plug-in test in Houston. Well, up until I overboosted the motor and shattered the #3 piston. Then divorce, then junked it. Not fun.
Oh the fun of CELs, drive-cycles, and emissions. The MSM had an intermittent CEL for several months, then suddenly one day, the car started running like **** and the CEL was flashing. I know it means "shut the ******* car off now, something is very wrong!". Figured out it was a bad coil-pack that seemed to randomly fail under no specific condition. Fixed the coil, did some other stuff, but the CEL would still come and go randomly. It started scaring me when we moved here to NC back in August.....and knowing I'd have to pass some kind of inspection to get NC tags. Scanned the ECU and got a P0421 (catalyst low).....which I suspected that the coil failure put raw fuel into the cat and killed it. So I ordered a O2 simulator to bypass the problem. Goofed the install because the installation instructions weren't terribly clear. Also bought a new rear O2 sensor on a hope, and luckily it was happy with the new sensor. It was fun trying to satisfy the drive-cycle with just a couple of days to go to get the car registered.....and it turns out that registering the car didn't require having any kind of emissions-passing paperwork WTF? I guess I figure at sometime when I get to trying to get the MSM to make more power, I'll gut the cat and run the O2 simulator so I don't have to worry about the inevitable emissions tests I will have to pass in the future here. Apparently when newly registering here from out of state, emissions isn't required, but is when renewing year-to-year.
Oh well. Off to finishing the steering rack swap......slowly de-MSM'ing the MSM of the "WTF" parts Mazda thought were good ideas. I'll be happy to have a normal turning radius back soon. Unfortunately, there is actually little information on doing this, so I'm having to figure out some steps and technique all on my own, and probably not exactly the fastest/most timely way to do this, but oh well. Figure when I'm done, I'll probably do some kinda of quick guide oh how to do it for future reference. All the stuff I found had to do with removing it from a subframe lacking an engine, or just doing a de-power procedure/looping the lines......nothing about removal/replacement.
Just for ***** and giggles, my Grandson's Miata started throwing misfire codes and the problem turned out to be a worn crank end and loose crank bolt. Luckily is was OK with the "loctite fix". It is a 2000 with 230,000 miles on the engine. Last TB was done prior to his ownership.
I figured WTH, and reset the ecu. Within one drive cycle, I am back to where I was before with the exception of an evap not completed. The second cycle cleared the evap test. For the second cycle I kept the speed between 40 and 50 vs 60 from previous attempts. There were long stretches of 40-50 mph. No change.
Is there a scan tool that will let me see if there are any attempts at completing the testing?
09-27-2017, 01:21 PM
0
WTF? I guess I figure at sometime when I get to trying to get the MSM to make more power, I'll gut the cat and run the O2 simulator so I don't have to worry about the inevitable emissions tests I will have to pass in the future here. Apparently when newly registering here from out of state, emissions isn't required, but is when renewing year-to-year.
