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Surely this isn't normal...
I've just joined the list, and after reviewing the archives as well
as the not terribly informative Haynes book on the car in question,
I'm hoping to get some information from the members here on an
issue that I haven't seen covered elsewhere.
I'm currently driving a friend's '85 Coupe GT while doing some
vintage/track-day prep to my '67 Alfa GT Junior. I'm really
enjoying the Coupe, it reminds me of all the good things about
the 1980 4000 I had for three years, with many of the shortcomings
addressed. (If the Coupe had fender flares, AWD and a turbo,
it'd be exactly what I wanted my 4000 to be... :-) I may not
give him his car back when my Alfa is completed -- it's
distinctive, comfortable, a pleasure to drive and reasonably
Except for this one baffling behavior. At 4800 RPM, in first,
second or third (I haven't found a long enough road to get up
to 4800 in fourth or fifth), the engine acts as though all the
pistons have come loose and are about to fly out of the block.
Shifting into the next higher gear returns to the smooth, fluid
transfer of power to the drive wheels, but it seems that the
car is just getting started when it bucks and jerks. The owner
opined that it's the rev-limiter kicking in at that RPM, and
that the tach is reading low. Sounds improbable to me, but...
About the only useful data from the Haynes is the suggestion that
some (unidentified in the book) models have a distributor rotor
cut-out at 6900 RPM, consistent with the 6500-RPM redline on
the tach. While I don't object to the presence of a rev-limiter,
I'd certainly like the 1700 or so RPM I'm currently not getting,
particularly as the car feels as though it's just getting into
the powerband a few hundred RPM before it shuts down.
So, some specific questions:
1 - is the rev limiter really designed to make the car feel
like a rifle butt to the back of the neck when it cuts in?
2 - any tricks to hooking a 5-cylinder up to an external
dwell-tach to get a "second opinion" on the in-dash tach's
accuracy, or do you just hang it off the #1 plug wire just
as on a 4-cylinder car?
3 - assuming the tach is accurate and the rev limiter is a
softer touch than I've described it... any ideas on where to
start looking for the culprit for this behavior? As I said,
the Haynes isn't very helpful in this regard -- it doesn't
even have wiring diagrams for this year's Coupe, which irks me,
so I can't look to see the schematic of the ignition system,
and it doesn't describe how the rev-limiter works (whether
it cuts ignition or fuel, for example -- it couldn't be
something as simple as a centrifugal weight, could it? I'll
just solder the damn thing shut...).
4 - I know that 4-cylinder coils fire at twice crank speed,
since there are two power pulses per complete revolution.
What's the ratio on a 5-cylinder -- 2.5? Could it just
be that the coil has gotten old and can't cycle the current
quickly enough to fire at, what is that, about 12k/min?
I apologize for the lack of hard diagnostic data at this point
in the troubleshooting process, but as I'm still very new to
this car (and it isn't even mine yet), I wanted to get some
advice from those who know before I simply started poking
around on my own.
Thanks for any experiences you care to share, and I look forward
to having fun on the list and with the Coupe! (If nothing else,
it's reawakened my dormant desire to own an Ur-Quattro, a yearning
that was almost unbearable when the Q's were new and I had my
sweet, if fairly slow, 1588cc 4000 4-spd...)