Fordnatics List Archive

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Mail From: (email redacted) (George Chang)

Hi Peter,
I am driving an '84 Crown Vic police cruiser with a stock 351W
and the infamous 2VV variable venturi carburetor. For a while one of
the temp sensors was dead, and the computer thought the car was cold all
the time, so it ran in open-loop configuration (ignoring the oxygen s
ensor). Mileage wasn't too bad, but the exhaust smelled really bad.
Now that I fixed the sensor problem, the car smells much better
when it is warm (closed-loop operation) and the cats are lit. But it
still smells awful when it is cold.
I hope this is of help.

Best regards,
George
.....................................................................

Fontana Peter wrote...
>The Pro-jection would look a lot more at home under the ducted hood of a mock
>'69 Shelby (you know - the air cleaner and all), but I don't want to trade
>away power or flexibility, and I've GOT to prevent *that exhaust smell* in a
>convertible. I'd even run cats to clean up the idle smell - any thoughts?

This read-only message was archived from a public mail list.
Mail From: "Fontana Peter" <(email redacted)>

> I am driving an '84 Crown Vic police cruiser with a stock 351W
> and the infamous 2VV variable venturi carburetor. For a while one of
> the temp sensors was dead, and the computer thought the car was cold all
> the time, so it ran in open-loop configuration (ignoring the oxygen s
> ensor). Mileage wasn't too bad, but the exhaust smelled really bad.
> Now that I fixed the sensor problem, the car smells much better
> when it is warm (closed-loop operation) and the cats are lit. But it
> still smells awful when it is cold.

Thanks for the info, but please help me sort it out. It seems from your post
you feel the "lit" cats cut the smell, but why didn't the cats warm up when
the temp sensor was bad (and therefore cut the smell then, too)? Based on
what you observed, it seems the temp sensor caused the smell - won't the
computer call for richer mixture when cold? Did that richness cause the
smell (and still cause the smell when cold) ?

I don't know myself - I just don't want to get cats if I don't have to.


Thanks.

This read-only message was archived from a public mail list.
Mail From: (email redacted) (George Chang)

>> I am driving an '84 Crown Vic police cruiser with a stock 351W
>> and the infamous 2VV variable venturi carburetor. For a while one of
>> the temp sensors was dead, and the computer thought the car was cold all
>> the time, so it ran in open-loop configuration (ignoring the oxygen s
>> ensor). Mileage wasn't too bad, but the exhaust smelled really bad.
>> Now that I fixed the sensor problem, the car smells much better
>> when it is warm (closed-loop operation) and the cats are lit. But it
>> still smells awful when it is cold.
>
>Thanks for the info, but please help me sort it out. It seems from your post
>you feel the "lit" cats cut the smell, but why didn't the cats warm up when
>the temp sensor was bad (and therefore cut the smell then, too)? Based on
>what you observed, it seems the temp sensor caused the smell - won't the
>computer call for richer mixture when cold? Did that richness cause the
>smell (and still cause the smell when cold) ?
>
>I don't know myself - I just don't want to get cats if I don't have to.
>

I'm trying to figure that one out myself. My impression is that
with the bad sensor, it smelled bad all the time. Now it smells much
better as soon as the car gets warm. And when I make an effort to be sure
the cats are lit, it is even better.
I wonder if the final oxidizing part of my three-way (or are they
two-way) cats are going out. Maybe the reducing stage helps to generate
the wierd smell of my exhaust. And maybe the oxidizing stage is so far
gone that the cats only work well when they are thoroughly warm. What
have other Fordnatics found?

Best regards,
George

This read-only message was archived from a public mail list.
Mail From: William Kenneth Neher <(email redacted)>

Mine has never had a bad smell from the cats , cold or otherwise. Maybe
it is something else. I did have to replace my cats though. they got
pligged up On the positive note, i did get the Dynomax's put on at
the same time!!

_________ _________
|________ | | Ken Neher Emory University
________| * |_______| 1983 5.0 Litre Crown Victoria Police Package

"Our Lady Of Blessed Acceleration, Don't Fail Me Now!!!!"- Elwood Blues