From: Bruce Stubblefield <audiblefeast@xxxxxxxxx>
\>Hello list,
The mighty 71 four-door (440) refuses to bend to
repair attempts. The shop and I have spent a lot of
time on this, but no soap. The mechanic I'm using is
an older guy who is quite familiar with old
carburetted cars. Though clearly not a brilliant
diagnostician, he's solved a number of other problems
on the car.
The symptoms: From a standing start or from
coasting at 0 to about 5 mph, flooring the accelerator
results in "backfire" popping out the top of the carb,
stalling or almost stalling. A slower, more gradual
acceleration does not show this problem. Also, car
surges or bucks intermittently on hard acceleration
from a stop under a load, as in accelerating up a
normal freeway onramp leading to an elevated road.
In the last month or so, new plugs, spark plug
wires and electronic distributor (mopar performance)
have all been fitted. Scopes both in shop and onboard
show normal electrical performance. Timing is
perhaps 5 or 8 degrees retarded. Aside from this
problem, runs fine on 87 octane regular. I also
frequently run 91 octane premium.
Carb (Carter, not a thermoquad) was just rebuilt,
with a new accelerator pump done twice, with no
improvement. The shop found a service bulletin in an
old 69-72 Mitchells book which described a similar
problem and gave a solution of re-boring some holes in
the carb and changing some of the metering needles.
Carb shop did this per the service bulletin, to no
effect. Mufflers and resonators are new.
Has anyone solved a problem like this? Do I
have to buy a modern carb?
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