98 Honda Civic Sensors Not Ready / will not pass inspection

Hi folks,
The Civic will not pass inspection in New York, engine light is not
on. The following codes show "Not Ready" O2(#1), CATALYS, O2(#2),
EVAC. (I know I need to drive the car after replacing emmision parts)
Replaced the following with Honda parts: the top(#1) O2 sensor($140)
and the bottom(#2) O2 sensor ($250)... The (#1) top O2 comes up ready
now, but the bottom (#2) O2 sensor still Not ready.. I changed the
thermostat for kicks but that didn’t help.. Not sure why it’s saying
EVAC not ready, when you loosen the gas cap you hear a vacum sound. We
put over 500 miles on thing too.. The owner of the inspection garage
called the state and they suggested the following: (this is nuts, but
we tried it) 1. Let the car sit for 8 hours start it and hold at
3000rpm until the cooling fan come on and drive it 50 to 60 mph for 5
minutes then stop for 5 seconds and repeat 3 times. 2. With a 1/2 to
3/4 tank of gas drive 65 mph for 5 minutes, stop remove the gas cap
and let it idle for 5 minutes and replace cap, then repeat 3 times.
The 3rd option I don’t remember off hand but it was similiar to the
others. Any suggestions whithout replacing the Cat?

 

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You need to provide the CODES (ie: P0420) since there are dozens of
things we could guess at. What's the mileage, history of the vehicle?

Have you topped up the coolant in the reservoir since the work was done?
That part is in your manual.

'Curly'

 

Maybe you need a new gas cap?

does that model have an air bleed port on the cooling system?
(my 94 GSR does,on the block)


Maybe you could get a used catalytic from a junkyard,for test.

 

Did you disconnect the battery at any recent point? That clears all the
flags.

That suggested "drive cycle" sounds bogus. Removing the gas cap and
allowing the engine to run will set an error code.

The drive cycle in essence ensures that the engine warms up all the way,
and is driven long enough, and under sufficiently varying conditions,
for all the systems to run their self-tests. The monitor flags are set
"ready" after each system passes its self-test.

Take the car for an hour's continuous drive, half highway and half city,
then shut the engine off and allow it to cool completely (at least five
hours). Now repeat your previous hour's driving. This will give you a
much greater chance to have all the flags set.

If the car is never driven very far, or never driven to fully-hot, some
flags will never become "ready".

Now, having said all the above, there are certain vehicles that have
known problems with monitor flags refusing to set. These vehicles are
given exceptional status at smog stations, and so achieve a pass even
with certain flags not ready. Your local dealer can look up any TSBs
that may apply to your car and that problem
(*if* such TSBs exist for your VIN, and they may not).

 

Just an aside, I drove from Topeka KS to OK City once, about 130-140 kph....
I left my gas cap in Topeka by accident.

Never caused a CEL.... and it didn't affect mileage, that trip is 475kms, I
only put in 8.5 gallons.

98 civic 5-spd, had about 165000 on it at the time, back in 2003.

t

 

This is a perfect complement to the monitor "readiness flags" issue.

If your MIL did not illuminate even with the gas cap off, then the ECM
never did its EVAP self-test. You would think it would have run a test
during such a long drive, but it did not.

This is why it is sometimes necessary to do the official "drive cycle" to
get all the self-tests to run so the monitors will all report "ready", and
why it's a bad idea to clear all the flags by disconnecting the battery.