The old adage "If it ain't broke, don't fix it" certainly applies here.
I have a 1976 TR6 with a 1969 engine that was running very good, but it
had been sometime since I changed points and condenser (which is
another story) and plugs, which I did last week. I heard a very brief
"hissing" sound when I removed the back plug but could not pinpoint
where it was coming from.
I started the car to drive around the block and all it did was miss,
sputter and backfire.
I recehcked all the gaps, drove again and it wasn't any better.
Last night I installed new plug wire set. It did not help. Today I
checked the timing and carbs, and everything seemed fine. A friend
said he thought there might be vacuum leak. I did not think about the
"hissing" sound again until he said that. He pulled the vacuum line
from the carb, sucked on it and the distributor plate moved only a very
short distance, about 1/8 inch or so. He said that the vacuum advance
unit diaphragm may have a leak, which would cause the engine to miss,
sputter and run bad. The engine had a slight miss at idle previously
but ran without a problem at speed.
My question is, does my friend's diagnosis sound right? Does the
distributor plate normally move more than 1/8 inch or so? And can the
vacuum advance unit be replaced without replacing the entire
distributor, and how is this done. The vacuum advance unit on this
engine does not have the micro adjustment.
BTW - About the new points and condenser: I installed them and checked
the gap. The engine would not start. I rechecked the gap but it still
did not start. Then I put in the old condenser with the new points -
didn't start. I put the new condensor with the old points - didn't
start. I finally put the old points and old condenser back in and it
started although it ran rough (which may be because of the problem
above). I looked at the package and discovered the points and
condenser that didn't work were Lucas parts. I bought another set of
points and condenser at a local Hi-Lo store (not Lucas) and the engine
started.
Has anyone else had this problem?
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