Car wont pass Smog Advice Please

My buddies 99 Carrera has 20k miles on the clock. Been sitting and battery was changed. One smog place told me the computer is not ready and the car has to be driven more, put about 110 miles on it, went back and said same thing, something with catalytic converter issue. Took it to another smog place and said it should pass but not 100 percent certain.. Any special way to get it ready besides just driving? How many miles do I have to drive for computer to get going so it will pass? Any tips would be greatly appreciated.

There is a very specific driving routine you need to follow to get the computer ready. Search for my thread from earlier this year.

Also, the less efficiently the catalytic converters are working, the longer it can take to get the drive cycle to complete - based on some threads posted here over the past couple of years.

Even the crappiest OBD-II scanner has emissions readiness monitoring. Much cheaper than paying the smog place $30 to fail your car.

It also depends on the state. Most states will allow one or two monitors to be not ready. A few are more strict.

Hopefully this will help , https://rennlist.com/forums/996-forum/978533-smog.html

The data needed for the test is not sufficient to test for the CC. If your looking to reset the Readiness Monitors this is the work sheet that I came up with from searching the net: Start engine, idle cold for approx. 2 min, 10 secs. Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs. Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins. Decelerate and come to a stop. Idle in gear* for approx 5 mins. 1..As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump andEVAP purge. 2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge. 3. Hold at a steady state speed of 55 mph for three minutes. OBDII monitors EGR, air pump, O2 sensors and canister purge. 4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions. 5. Accelerate back to 55 to 60 mph at half throttle. OBDII checks misfire, fuel trim and purge again. 6. Hold at a steady speed of 55 to 60 mph for five minutes. OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions. 7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge. just hold the following RPM ranges from 2-5 minutes: Idle 1500 2000 2500 3000 Idle the checks usually happen before the 5 minutes is up, but without a scan tool hooked up you won't know when it happens. The sequence is not set in stone... you can do some of them out of order... They will check and reset the individual monitors as your driving...

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Be sure the gas is fresh and the right grade of octane. If available where you are I'd recommend Chevron Supreme. But Shell V-Power ok too. Any top tier name brand gasoline should be ok. I'd stay away from discount gasolines, supermarket gasolines. I never had any problem getting the readiness monitors to complete. I'd just drive the car. At some point during my 30 mile work commute the monitors would be complete I just never bothered to constantly check them with an OBD2 code reader to find out when. The 30 mile commute is nothing special. Cold start. Brief idle. A few minutes of surface street driving. Then on the freeway. No real hard acceleration or high RPMs because the engine was still cold and would remain cold, *below* operating temperature based on coolant temp, for maybe 10 miles. Used to be I could maintain freeway speeds all the way to work but no more. Always encounter some congestion, slow going, even a brief stop/go mess. Still the readiness monitors get set to complete with no real effort on my part. Some drives I use the A/C. Sometimes -- in the winter -- the heater. Most of the time though neither. I had one time my 2002 Boxster failed smog. All readiness monitors were set to complete. Gas was fresh. Engine in good tune. Talked to both senior Porsche techs -- separately -- and both first expressed surprise knowing the car and how I keep it up and how I drive it and both recommended the same thing, essentially an Italian tune up. So I took the car out east of here on some winding back roads where I could open the engine up some -- at least in the lower gears -- and then after 15 miles or so of this catch the freeway for a return drive home. Just a few hours later back at the same smog check station for a retest and the car passed smog with flying colors.

You Tube

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Find someone with a PIWIS2 to run the short test to "Ready" all readiness monitors. That's if your friend's car has all of the components that actually work.

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There are ways around it if you have a piwis. I had my last car reprogrammed to be ROW. Then, it doesn't even look for the smog crap. Passed smog with it.

The PIWIS or ROW reflash is the best idea in my experience because attempting a fix usually has a carbon footprint way bigger than the benefit of the SAI .But you must plug the Vacuum system in an intelligent location otherwise you may develop other CEL codes.Understand you may not have any SAI problem just a deficiency in patience !It can take hundreds of miles to set the Readiness Monitors. Some set far more quickly.Who knows why? This Ready Status issue is covered in geekish detail on Renntech.Check both 996 and Boxster Sections. You need a Diagnostic tool at least as good as Durametric to make any logical progress. The problem is that there are many (I have found 5) different Drive Cycles with many anecdotal /non-technical/non replicated variations of each and lots of clues(?) like different brands of gasoline(really,Top Tier isn't good enough? evidence?) is this an oil brand thread yet ? Tellingly there is no single Drive Cycle that always works. Worse there is no explanation (that I could find) that explains definitively which specific part of the any Drive Cycle sets which Monitors. To test the vac system, start at the "Y" using your annotated AutoAtlanta diagram.Use a hand vac pump with a gauge.(HF is fine) .Use low vacuum.Look for a sloooow leak. If you do have to start dismantling, be sure to replace all the hose with high quality silicone and all the connectors with brass not plastic. Be super careful testing the components - no high pressures ! You are looking for slow leaks at low vac/pressure. Neither the electric c/o valve nor the air c/o valve are expensive so replace both? Test the reservoir under water with pressure not vac Particle weave had a hack component for this. The SAI pump can be (diy) rebuilt.But repairs may be more difficult than it at first appears.No it doesn't just run at cold start for 90 seconds.It has a self test while the engine is warm sometimes - so others say.It would be impossible to hear at normal road speed.Who knows if that is part of the Drive Cycle or not? If your engine is carbon-ed up, the SAI ports in the cylinder heads may be (partially) plugged.In which case ,no repair or replacements will be effective(carbon footprint!). ROW reflash? Good luck and I hope these suggestions helped. Tell us what worked for you . Please don't get the impression I understand this issue. I don't.