Honda Car Forum

"Al Reynolds" <ajr-news@bat400.com> wrote in
news:rDsPl.109195$5J5.29114@newsfe29.ams2:

> "Tegger" <invalid@invalid.inv> wrote:
>>
>>> 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)
>>
>> What exactly is "fast idle" as defined by your MoT?
>
>
> When you first turn on the car, it idles at about 1500-1800 rpm for a
> short period, and then settles to about 700rpm. The first period is
> the "fast idle" period.
>



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
short duration.

AFAIK, no North American jurisdiction attempts such a thing.


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

"Tegger" <invalid@invalid.inv> wrote
> 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
> short duration.
>
> AFAIK, no North American jurisdiction attempts such a thing.
>
>
> --
> Tegger


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:
http://www.motuk.co.uk/manual_730.htm

"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
the results."

So it's a held fast idle.

Al

"Al Reynolds" <ajr-news@bat400.com> wrote in
news:ZqCQl.132512$5J5.13476@newsfe29.ams2:

> "Tegger" <invalid@invalid.inv> wrote
>> 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 short duration.
>>
>> 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:
> http://www.motuk.co.uk/manual_730.htm
>
> "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 the results."
>
> 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.


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/