Will Zehring writes:
> Okay, after a few previous boastful postings I guess its my turn for humble
> pie: on the drive home Friday the '63 B developed a misfire. That is, I
> feel a subtle lurch in the car and an interruption in the normal sound of
> the engine, pretty frequently too. No backfire and no obvious sound from
> the carbs. Only happens under load, not in the garage blipping the
> throttle. Is this just bad timing? There is no knock. Keep in mind I have
> new wires, new plugs, new coil. Is this a carb problem? Is my coil bad
> already? I am certain this is a problem that just developed. In earlier
> drives in the car it ran fine. Any and all advice would be
> appreciated.
You may recall that I've been three weeks of debugging a misfiring
problem on my '74 TR6. It turned out to be play in the throttle
linkage to the rear carb. (Front carb linkage was ok.)
However, I received many excellent responses on things to look for.
>From the many responses I received, I would suggest to suspect
primarily the ignition system. You mention that wires/plugs/coil are
all new. I would suggest pulling the plugs, and see if any of them
show indications of the problem. Is one of them particularly fouled?
(In my case, my rear three plugs were carbon fouled, and the front
three were fine, pointing to a rear carb related problem.) Any
abnormalities will help point to the problem.
Re-check the timing. (I would suspect this to be the most likely
culprit.) Check the functioning of the vacuum advance or retard on
the distributor. (Is there one on a '63B?) If there is mechanical
advance, is it functioning? (Check timing against manual spec at
various rpm.)
Go out to the garage on a dark night, start the car, raise the bonnet,
then turn off all the lights (not just the car's lights, but the
garage lights, overhead light, and any other lights you have -- you
want it absolutely dark), and look at the engine compartment. If you
can't see anything at all because it's now pitch dark in the garage,
that's excellent. (Don't ask me how you're supposed to find the light
switch now that it's pitch dark in a cluttered garage, with an
oil-slicked floor, although a flashlight (torch to the Brits) helps.)
Frequently, however, you'll be treated to quite a light show of
current leaks from wires, distributor, plugs, etc. Anything seen
should be fixed.
Some more obscure things that people suggested checking included a
tiny bit of oil on the distributor points, or any other electrical
contacts (any is TOO much), a frayed low tension lead.
Good luck, and let us know how it turns out...
--ken
|