I was happy. I'm off the hook for two more years.
The Walker has been on the car for something close to 20,000 miles, and I
was honestly not expecting it to actually be functioning by the time smog
My primary issue with the Walker is the horribly loud ticking that it and
its spring bolts make ALL THE TIME. I let the mechanic (not my usual guy)
talk me into an aftermarket Walker A-pipe because he said the two would
mate better than an OEM A-pipe and a Walker cat. BAD choice. The damned
assembly is noisy as all get-out. I almost want to smear that stupid A-pipe
with salt and chlorine in order to get it to rust out really fast so I can
justify the cost of a new OEM A-pipe and bolts.
Always good to see these reports. I make a mental note and then often
end up groups.google searching for some of Tegger's updates somewhere
down the line.
One interesting point to me: His Integra is passing smog with an 8-
year-old, 146k miles O2 sensor. I had almost talked myself into
replacing these every 50k miles, based on some suspicions on why my 91
Civic a few months ago could not get past smog.
This was interesting to me as well because I did have considerable concern
about the oxygen sensor before this test.
The original sensor was replaced on account of the Check Engine light
having come on twice with a Code 1 in the months before the first test.
The current replacement sensor has not yet tripped any codes, but it's
getting very close to the mileage where the original sensor began to give
Maybe Denso has improved their sensors since 1991. And maybe the newer
gasoline is formulated to be kinder to oxygen sensors. The original sensor
spent all of its life in the presence of MMT, which can cause deposits on
certain emissions control hardware. The new sensor has seen little MMT.
I've seen numerous recommendations both on and off-line that sensors should
be replaced every 60K as a matter of course. But at over $300 for new OEM
Denso, it seems to me that ours ought to last quite a lot longer than 60K.
And it seems like they do exceed that figure by a considerable distance.
Did you ever post your numbers when the Civic wouldn't pass?
For my 91 Civic and now 93 Civic, I can get the new OEM Denso oxygen
sensor through Amazon for about $30. www.densoproducts.com is almost
No. I had it tested several times. Mostly it failed at idle but not at
high speed. The last reading before I sold my 91 Civic (to people
living in a no emissions testing required county):
Failed idle with
HC = 460 (limit is 180)
CO = 1.8 (limit is 1.2)
My last theory is that I had air leaks at the throttle body gasket
(you could hear them using some Tygon tubing as a stethoscope). A
little Hondabond sealant fixed this. But I think the air leaks may
have resulted in rich running for so long that the O2 sensor was
fouled. I did some checking of the O2 sensor and it was not bouncing
around 0.45 volts the way certain web sites said it should. So my next
step would have been to put in a new O2 sensor. If a new sensor would
not fix it, then I think I would have done a compression test and seen
if the engine was just too old and worn to pass emissions. Miles per
gallon was still pretty good when I sold it, so it is hard to say.
At honda-tech.com I think the threads that are left unresolved most
often are the smog ones for the older Hondas.
Just for comparison, my 97 Accord Wagon EX (185000 miles) just passed its UK
MOT emissions test again with the following:
Fast idle test:
CO 0.09% (limit 0.20%)
HC 13ppm (limit 200ppm)
CO 0.13% (limit 0.30%)
As you can see, we don't have an NO test, or a 25mph test, or test HC at
idle, so we're obviously not as fussy. As far as I know the cat and other
emissions components have not been replaced ever on this car. I get about
Nonetheless, I was as happy as ever to pass emissions for another year. The
only thing I failed on was the two number plate bulbs, which were working
but "not bright enough"...
At hot idle (when the cat is actually functioning) that initial elevated
RPM lasts for only two seconds or so, just long enough to get the oil
pressure up quickly. I'm really surprised they'd try to test you on such a
AFAIK, no North American jurisdiction attempts such a thing.
OK thought I'd check this out properly as I wasn't sure of my facts. Turns
out I was wrong - according to the MOT manual at:
"fast idle test: Raise the engine speed to a fast idle between 2500 and
3000rpm and hold steady. Note the readings for CO, HC and lambda, and record
So it's a held fast idle.
That's not "idle" by /any/ stretch. I think their terminology is a bit
suspect. It actually sounds like a no-load test at cruising RPM's, which is
probably being done in lieu of a dyno test. Maybe your MoT dynos are not
set up for emissions testing.
A typical North American off-idle test is the ASM2525, which uses a dyno to
impose a 25% load on the engine at a speedometer reading of 25mph.
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