A clear case of quantum electrodynamic discontinuity. The automatic is
sufficiently divorced from the spirit of Lucas to accommodate the addition
of electronics newer than 1975. You might try exorcism.
Another approach would be to put an ignition scope on it and see what's
happening to the primary voltage. My guess is that the problem is related
to spark advance, as in, not getting much. I take it you've checked out
the spark vigor--I keep a plug with an alligator clip safety wired to it
and the ground electrode snapped off so I can quickly see what the spark
looks like. It should jump 10MM easily with a satisfying pop and a nice
whiteish-blue color. Pink is bad, so is thready blue, though very fast
rise time coils and multispark ignition can look pretty flimsy when it's
really hotter than a pistol.
Polarity reversal of the coil can be a big deal with electronic ignition
where it's not so important with points.
You didn't mention swapping out the trigger--I assume you tried it. With
electronics, all bets are off--anything can go bad in the first few hours,
and then it usually lasts forever until you do something silly.
I kind of wonder about the ballast resistor. Do the instructions call for
one? A lot of electronic ignitions don't use them--you don't get the long
current cycle in the coil (dwell). With a quickly rising pulse the current
is sufficiently limited by the inductive reactance of the coil.
Bottom line--I don't have a clue.
-----Original Message-----
From: BRITPAC@aol.com [mailto:BRITPAC@aol.com]
Sent: Thursday, August 29, 2002 3:56 PM
To: fot@autox.team.net
Subject: electronic ignition
Need some help, guys:
I'm having trouble making a Crane system work on a TR6. I have exactly the
same combination on the automatic TR6 and it works great.
Here's what it's doing:
Comes in running fine on points. Replace the points with the trigger and
amplifier, and it runs 'weak': stumbles and pops on acceleration and it's
slow to rev.
Here's what I've tired:
Cut a hole in an old distributor cap to make sure the rotor is lined up
right. Adjusted timing and the trigger position in relation to the rotor
position. Tried a matching Crane coil with ballast resistor. Tried other
amplifiers. Checked the ground. Checked for voltage to the amplifier and
to
the coil.
Put the points back in and it runs perfectly. As I say, I have the same
set
up in another TR6 and it runs great.
OK, I'm licked. Any ideas?
Steve Hedke
britpac@aol.com
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