Ferrari Mailing List: Re: 308 QV emissions failure and possible misfire

[Alexander Ishii (alexishii]

> Just-as-Important will be the rubber seals you'll need that go around the
> injectors.  I have seen two types used for QV engines: a black-rubber donut
> held-fast with a Cir-clip and a 'mushroom' seal that fits underneath a
> stainless-steel threaded cap that the injector fits-through.  You'll want to
> get the right ones, they are not interchangeable.

Ordered from Rutlands.  Claim is they are sending the right ones for my 84,
we shall see...

Updates:

1) Checked extenders; all looked fine.

2) Checked distributors; did not notice anything that looked "off".

3) Cleaned various electrical contacts.

4) Did the "cut quarter-inch" trick on suspect vacuum hoses.

5) Tried carb cleaner on various potential leak points; no affect on idle.

6) Cleaned throttle body.

7) Pinched-off various vacuum hoses; no obvious effects.

After all the above, basic problems remain unchanged.  Though I will admit
that the transition between cold and hot running now seem smoother (car used
to sometime "hunt" between the two modes for a short time).

New Question:

After pulling all the various access panels, I could find no obvious way to
probe the O2 sensor (at least not while still leaving it "in circuit" to see
the feedback cycle), so I decided to just replace the sensor as a precaution
(motivated by emissions-fixing 101, combined with the fact that the sensor
is obviously the one originally fitted to the car).

Much to my surprise, however, there is also no obvious way to get a wrench
on the sensor from below the car.  The problem is that there is a small
heat-shield attached to the cat that blocks access to the sensor (various
pictures of O2 sensor replacements on the web don't show this shield, but it
is on my car, nevertheless).  I can reach around it and feel the sensor from
above, but from that angle there is not enough space between the shield and
the bottom of the boot compartment to get a wrench in.  Near as I can tell,
the shield looks to be permanently fixed to the cat...

Anyone happen to know for sure that the shield actually just slips/snaps off
(obviously don't want to break a weld trying to find-out by "experiment")?

If the shield is permanently attached, I'm not sure I see any alternative,
other than to drop the cat out of the car...

    -- Alex

> --- On Thu, 12/23/10, Alexander Ishii <alexishii [at] mindspring.com> wrote:
>> 
>> From: Alexander Ishii <alexishii [at] mindspring.com>
>> Subject: Re: [Ferrari] 308 QV emissions failure and possible misfire
>> To: "Michael" <Cavallino_Rapante [at] yahoo.com>
>> Cc: "The FerrariList" <ferrari [at] ferrarilist.com>
>> Date: Thursday, December 23, 2010, 10:56 PM
>> 
>> 
>> Hi Gary,
>> 
>> I¹m going to order a new set of injectors tomorrow.  Figure that even if they
>> are not the problem, if the current ones are suspect, than I won¹t be
>> confidently move on to other possibilities.
>> 
>>     Cheers,
>>     Alex
>> 
>> 
>> on 12/23/10 12:29 PM, Gary Reed at gary [at] garyreedsales.com wrote:
>> 
>>> After 26 years, your injectors are probably all shot.  The factory ones were
>>> steel and they corroded over time.
>>> 
>>> Replace all of them with upgraded Bosch "brass" injectors.
>>> 
>>> Gary
>>> 
>>>> 
>>>> ----- Original Message -----
>>>>  
>>>> From:  Alexander Ishii <mailto:alexishii [at] mindspring.com>
>>>> <http://us.mc318.mail.yahoo.com/mc/compose?to=alexishii [at] 
>>>> mindspring.com>
>>>>  
>>>> To: Gary Reed <mailto:gary [at] garyreedsales.com>
>>>> <http://us.mc318.mail.yahoo.com/mc/compose?to=gary [at] garyreedsales.com>
>>>>  
>>>> Cc: The FerrariList <mailto:ferrari [at] ferrarilist.com>
>>>> <http://us.mc318.mail.yahoo.com/mc/compose?to=ferrari [at] ferrarilist.com>
>>>>  
>>>> Sent: Thursday, December 23, 2010 7:58  AM
>>>>  
>>>> Subject: [Ferrari] 308 QV emissions  failure and possible misfire
>>>>  
>>>> 
>>>> 
>>>> Hi All,
>>>> 
>>>> So my 84 QV has been stubbornly failing  emissions (in NJ), and after some
>>>> repeated assertions by my usual mechanic  that "all seems to be well", I've
>>>> found myself having to try and figure out  the problem myself.
>>>> 
>>>> At the moment, the car is not idling right in my  mind (despite what my
>>>> mechanic says).  For one, the idle speeds  "hunts" a bit; not enough to be
>>>> seen on the tach, but enough to be felt as  a slight change in the
>>>> vibration
>>>> frequency of the engine.  Second,  every couple of seconds one gets a
>>>> just-audible muffled "pop" sound from  the engine, accompanied by a slight
>>>> puff of extra exhaust out of the tail  pipes (no sound out of the air
>>>> intake
>>>> system).  Also, the car is  running sort of on the hot side (coolant temp
>>>> "idles" at 195).
>>>> 
>>>> Plugs  and wires were changed not long ago, but other than that, nothing
>>>> much
>>>> has  required much tinkering in many years.
>>>> 
>>>> The "pop" has me thinking than  one-or-more of the cylinders is
>>>> intermittently misfiring and dumping some  un-burnt fuel into the exhaust
>>>> manifold (where it is igniting and  "popping").  Given the "every couple of
>>>> seconds" nature of the  problem, however, I have little doubt that all the
>>>> sparks will look fine  when I try the usual tests.  Anyone have any
>>>> suggestions for how I  might try and zero-in on the faulty system (short of
>>>> swapping-out every  part one-by-one until the issue goes away)?
>>>> 
>>>> Also, it has also occurred  to me that the problem might be that the
>>>> injectors are not atomizing  properly, and leading to an complete burn (in
>>>> turn leading to exhaust  manifold ignition of the leftover fuel).  Has
>>>> anyone
>>>> seen symptoms  like the above be remedied with replacement of the
>>>> injectors?
>>>> 
>>>> All  thoughts/opinions/experiences would be appreciatively  accepted.
>>>> 
>>>>     Cheers,
>>>>      Alex
>>>> 
>>>> 
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>> 
>> 
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