Want to make sure that they can't detect the old codes when I take it in for emissions and they OBDII it. (it's a 96)

and does it take time to reset (couple hundred miles or so) before it is able to trigger again?

I have to go in for emissions soon and it is questionable if I'll pass as I'm getting an intermittent CEL P0420 "Catalytic system below efficiency". It may just be a sensor or the cat itself but I want to make sure if they plug it in, the CEL codes are truly gone and reset.




Modified by scott1ct at 9:58 AM 7/24/2007

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by scott1ct &raquo;</TD></TR><TR><TD CLASS="quote">Want to make sure that they can't detect the old codes when I take it in for emissions and they OBDII it. (it's a 96)

and does it take time to reset (couple hundred miles or so) before it is able to trigger again?

I have to go in for emissions soon and it is questionable if I'll pass as I'm getting an intermittent CEL P0420 "Catalytic system below efficiency". It may just be a sensor or the cat itself but I want to make sure if they plug it in, the CEL codes are truly gone and reset.

</TD></TR></TABLE>

Yes, the code will come back within a half hour usually. If there is something wrong with the cat, disconnecting from battery won't fix it. Plus if it is an emissions problem, it will more than likely show up in the sniffer

 

So if the code doesn't come back within a short time, it could survive the testing?

My CEL will stay off anywhere from 200 to 1000 miles spanning a week to a month before retripping the code. This has been going on for months.

If it is a partially failing cat or just a failing O2, I'd like to pass this and worry later. Planning on trying the few tricks of high octane fuel, new plugs and oil and ethanol in the tank to get by. If it is just at the point of tripping the CEL and not constant, any thoughts of passing a state emissions?

 

Try all that stuff you mentioned and maybe a good sea-foaming.

The thing is even though the computer didn't realize it yet, you are still putting out too high of an emission of something. Might get caught on the sniffer during inspection and it might not.

 

Won't sea-foaming wind up throwing a lot more carbon and deposits onto the O2 sensors which might completely gum them up?

The 94-97 accords had a emissions warranty to cover some problems with it and the OBD system so I'm hoping my CEL is related to a faulty intermittent sensor. Referenced here: https://honda-tech.com/zerothread?id=2033995

 

That is a good point. I don't know though. Out of all the seafoaming threads I never really saw anybody point out changing O2 sensors or mentioning if the can warns or not.

 

Yeah, I may be in a short term fix mode to pass but I'll be sure to take it to a testing station with a trustworthy mechanic so if it does fail, I'll know the damages.

I know auto-rx has a cleaning and rinsing phase that both run thousands of miles where it will sludge out a lot of deposits and gum the filter. I'm pretty sure some will wind up out the exhaust and would throw the hydrocarbon numbers up. I'm assuming seafoam works the same way of releasing the build-up as auto-rx but I haven't tried either.

 

This just came up so wondering if anyone knows. Some cars have a break-in period after the CEL has been reset where it takes an amount of time or a number of engine starts before it allows another reading to be taken. Is this true for OBDII accords (any year)?