jim beam wrote:
> Steve wrote:
>> robb wrote:
>>
>>>
>>> maybe the emmision machine was reading 2700 when he had it reved
>>> up to 5K ? i do not know but someone probably knows there are
>>> alot of experienced and smart people here.
>>
>> Well, it was stated that the tester was having a hard time positioning
>> the machine's tach pickup...
>
> that's the worst thing about the op's description of the test - the tach
> reading, unless it's a obdII vehicle, is taken by putting a sensor on
> one of the plug leads, under the hood, not a "paddle" on the dash.

Actually, I've seen OBD-1 inspections done on machines where a mag-mount
antenna is stuck to the underside of the hood or fenderwell near the
engine, not on a plug lead. Not all machines are made the same, and I
immediately thought that design was just begging for a frequency error-
crappy machine design if you ask me. But even clamping on a plug wire
can have an error. I have used enough induction-pickup timing lights
that get enough cross-talk between plug wires that they sometimes fire
multiple times per distributor rotation, unless you position the pickup
*very* carefully. And with a single antenna system like I described, you
can get exactly the opposite problem on waste-spark ignition systems.
The machine expects to pick up all spark pulses and divide by 4, but if
it only picks up the spark from 1 coil and divides by 4, it will get 1/2
the correct RPM.

and
> revving the engine is perfectly kosher if the cat is cold or there is a
> misfire.
>
> bottom line, the test was good.

If the description was so poor, then you have no stronger case that it
was good than I have in saying that it is questionable.

> the op's description was unreliable.

Some aspects were, I'll give you that. He admitted he wasn't paying
close attention. But if he *EVER* saw 6000 on the car's tach, that alone
make me suspicious. 3500 RPM or so- sure. 6000? No WAY.

> and his paranoia unjustified.

MAYBE.

$30 for another test will remove all doubt. Cheap. If my wife came home
with the same story, I'd take it myself and have it tested before I
started throwing money at emissions parts.