Hi all,
Ok, I've been having this problem for months now and still haven't figured
it out. After taking a high speed run for an extended period of time
(doesn't have to be very long, just a few minutes really) my engine doesn't
want to idle when I pull to a stop. I have my idle speed set around 1000.
What happens is the rev's come down to about 1000, it quickly drops to about
400, putters a little bit, then dies. I can immediately restart the engine
and everything is fine. This will happen for a few minutes after pulling
off the interstate then it drives perfectly normal again.
This occurrence is very reproducible and is just about guaranteed to happen.
Sometimes the engine does stall on occasion without a highway run, but it
doesn't happen often and I can't purposefully reproduce it - it just kind of
happens.
I found some vacuum ports on the carbs that were capped but the caps were
falling apart. I replaced these caps and the situation has improved a lot.
If I'm watching the tach I can save the engine by giving it a little gas,
unlike before I replaced the caps where nothing could save it. I'm using
just standard engine oil in the dashpots which are filled to the appropriate
level.
I'm pretty sure the mixture is set OK as the spark plug color is about what
is should be. If anything I'm a little on the rich side.
I am unsure if this is causing or adding to my problems, but when I replaced
the caps on the carbs I also rerouted a few hoses. Instead of having the
breather lines go straight in the carbs (getting them dirty inside) I routed
the line instead going into that center port on the intake manifold going
through an off the shelf PCV valve. Most of my effort up to this point has
been trying to eliminate vacuum leaks in the part of the system.
Finally, the car is 1974.5 with the good ol' Zenith Strombergs so nothing
has really been modified in the intake system.
Anyone have any ideas on what to do? Thanks for the suggestions!
Steven Altomare
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