Re: 308 QV emissions failure and possible misfire |
<– Date –> <– Thread –> |
From: Gary Reed (gary garyreedsales.com)
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Date: Thu, 23 Dec 2010 09:29:35 -0800 (PST)
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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 -----
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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- Re: 308 QV emissions failure and possible misfire, (continued)
Re: 308 QV emissions failure and possible misfire Gary Reed, December 23 2010
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