doje

So, living in California I have to deal with bi-annual smog checks. This year I took my 97 Corvette in and they hooked it up to the smog machine through the OBDII port. The smog machine came up and said that it was unable to establish communication with...

A) Catalyst
B) Secondary Air System
C) Oxygen Sensor

The smog system will still allow you to pass with two failed communications, but not three.

So, the smog guy said that perhaps my battery had been disconnected and the car needed to be driven 60-100 miles for the systems to re-log new data.

Well, 1000 miles later and still having the same problem. Can anyone tell me what could be causing this?

doje

ttt

BudgetPlan1

Ever had a dyno tune done? Sometimes they turn of the system readiness tests for certain things and you'll get messages like you're getting.

C5Spirit

Dave I heard that this is the way they were going to start smog checking our cars through the OBDII port. Did they have you on the roller also?
What cats do you have on it, OEM or hi-flow? Is the air pump turned off?
Could you have bad O2 sensors?

doje

Yes I have, but I spoke to the tuner and no systems were turned off.

They still put the car on the rollers and use a sniffer. Cats are OEM. I suppose there could be a problem with the O2 sensors, but wouldn't the car be throwing a code?

C5Spirit

I believe you would be getting codes.
The air pump from what I understand runs for about 30 seconds to aide in heating up the front O2s.
So the OBDII port I guess is to go in and prob around to see if you have other than a stock tune..??
You may have to go back to the tuner and see if they know of a smog place that will work with their tune...
We in CA need answers on this type of smogging..

briann510

They cant tell if you have a non stock tune plugging into your OBDll port for a smog check but I heard in the future they are going to be able to check for non stock tunes as well as systems turned off/bypassed with new software/machines they are getting but ill just load the stock tune in out in the parking lot, have it tested and then re-load the other. If its a computer you can always cheat the system easily no matter what they try to check.
I have a non stock tune as well as air pump unplugged and off the car and turned off in tune and they didnt pick up on it and I passed.

C5Spirit

I believe my air pump is still in place and turned on.
I have rear O2 simulators. So as far as having the stock tune installed means I have to go to the tuner and then hopefully to a smog shop they work with...

tblu92

Sounds like you have headers---They will always throw sensor/catylist codes--BUT the secondary air system--If it is not working,then as mentioned your 02's won't heat up properly and will domino to 02 codes---I would work on the secondary air system---it would be the easiest to fix --leaving you with the allowable 2 "readiness tests" that are not complete----The 97-98's are known to have the air tube ports plug up with carbon---make sure they are open and clean---check your secndary air check valves--dependening on your DTC codes--you should be able to narrow down the problem or bank--ALSO even though you may not have a current check engine lite--you can still have some stored codes that will pinpoint your problem--have it scanned and look for the history codes--

briann510

Just have a tuner turn off all the crap and be done with it....It takes like 2 mins to turn off the stuff affected and snog station machine will never know.

doje

who do you recommend? The tuner I contacted wants $100 to tune them out. Seems high for a couple minutes of work.

0Brian@RPT

What was the code for the Secondary Inection? The Seconday Injection is the AIR System that heats up the cats during start up. If the check valves are not working, you can throw codes for the catalyst and rear O2 sensors.