Steve, I'm gonna take my best wild guess here, but I would suspect the
electronic ignition. These things are potentially prone to having problems
when they get hot. I would at least rule this out by installing a good set of
points. If that doesnt help, I am not personally familiar with the '74 but
isnt there some sort of themo vac switch on the radiator hose? Perhaps this
isnt working right. Good luck. John - 76 TR6
Hi-
For those of you familiar with the 74 TR6, I have a mystery problem. My
car is behaving as if it is running lean, it is missing/hesitating at speed.
I really went through the vacuum connections and even went as far as
replacing the manifold gasket. I cleaned the charcoal canister. I went
through the carbs and checked the diaphragms and the float bowl levels. Fuel
delivery looks good too. The timing is set correctly and looks stable. I
have a bosch blue ignition coil and electronic ignition that has never given
me trouble. New(er) wires, etc.
So what happens is that the car starts fine and runs fine until it warms up.
Once hot the missing starts. Even when hot, the car idles fine though. What
is confusing to me is that once hot, pulling the choke to enrichen the
mixture has little effect if the problem is with too lean a mixture,
shouldnt this fix it somehow? I have the carb needles adjusted fully rich
and if I lean them out at all the problem gets worse. The plugs look pretty
white too. The problem was originally there only when taking off from a
stop but it has steadily gotten worse.
One clue if that if I pull the vent tubes off the carbs (the ones near the
de-accelerator valves), the idle gets a little lower which, according to
what I have read should not happen.
Well, I hate to bother you guys with this one but I have been trying to
crack this problem for weeks now and I seem to be no closer. If anyone has
any other ideas on what I should try, I would appreciate any advice since
top-down weather has arrived here.
Thanks,
Steve
Channel Islands, Ca.
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