SMOG help - ECU data not being ready for smog test

[slamstrom]

I took my 97 NSX in for a smog test and everything passed except for missing Oxygen Sensor monitoring, EGR system monitoring, and Evaporative system monitoring data in my ECU. The smog technician asked me did your battery died recently? My reply was yes. He said that I need to drive my car around for about 40 miles under 65 mph, and bring the car back for a retest, because those data are missing from my ECU. I guess the dead battery wiped out the data stored in the ECU, and I have not driven the car enough to store new data.

I drove the NSX for about 60 continuous miles all under 65 mph (very hard to do). When I got home, I use my OBD2 scanner to check if these 3 items are now ready and registered in the ECU. The Oxygen Sensor monitoring, and EGR system monitoring is now ready and good to go. However, the Evaporative system monitoring is still not ready.

What else do I need to do to get the Evaporative system monitoring ready and registered in the ECU before going back to re-smog. Do I need to drive more miles and cycles? I am not getting a CEL and my OBD2 scanner did not trigger any DTC or error code. Idle is steady and normal. Any assistance or suggestions are greatly appreciated. Thanks in advance.

 

[slamstrom]

Update, and information for those who may experience the same issue in the future.

After driving around for a total of 100+ miles the Evaporative system monitor is still not ready. I was found multiple/similar drive pattern/cycles to get the flags to be ready, but nothing to working yet. I will continue to try and get the Evaporative system monitor to be ready. In the mean time, I went to talk to multiple Test Only smog technicians including the place I took my car to. They all told me the same thing. The important info to know is that for cars between 1996 to 2000, you are allow a maximum of 2 system monitors to be not ready for functional test. For cars 2001+, you are only allow a maximum of 1 system monitor to be not ready for functional test.

I took my car back for a re-test and passed with flying colors on the emissions side of the smog test.

 

[FogCityNSX]

My buddy's 96 F350 w/ 460 had the same issue. Fixed all the emissions issues, ecu got reset, hooked it up to the smog machine by the same mechanic, same day just 40 miles later.....NOT ready. Drove around another week and covered about 200+ miles I believe. Passed with flying colors.

California truck

 

[nikey22]

anytime you disconnect your battery, it'll take some driving in all conditions, load, fast accel, uphill, downhill etc etc for the ECU to acquire data. Smog test after say 200miles or driving or so...

 

[PATCHEZ]

The ecu only test evap every so often and your gas needs to usually between 1/4-3/4 before it will run its test.

 

[slamstrom]

The ecu only test evap every so often and your gas needs to usually between 1/4-3/4 before it will run its test.

Thanks Justin. I think the every so often part is what's I have to wait for. I started with a 1/2 tank at the beginning of my drive cycle. I even refilled my gas tank to about 7/8 full think that the gas tank can't be full. Luckily, I good for another 2 years, but I still want to get the Evap system flag ready. Hopefully that every so often is within the next 2 years.