[Healeys] ignition miss

[Bob Spidell]

The fact a "high performance" coil--hence higher secondary voltage--made the problem worse indicates there is a leakage of secondary voltage somewhere (higher secondary voltage may cause breakdowns in the secondary ignition system--why "HP" coils aren't necessarily a good thing).   Also, changing the distributor didn't help much, indicating the problem is elsewhere.

With the HP coil in, run up the car in a dark (ventilated) garage, watching the ignition system closely.  Look for arcing on all the components.   Just 'cause cables "look good" doesn't mean they are.  Check plug leads with a DVM (digital voltmeter) and inspect closely.  Could be a bad terminal on one lead.


bs

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Bob Spidell         San Jose, CA        bspidell at comcast.net
'67 Austin-Healey 3000             '56 Austin-Healey 100M
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 -------------- Original message ----------------------
From: "Brits'n'Pieces (Eric Frenken)" <lists at brits-n-pieces.com>
> Hello,
> 
> a friend of mine has a BJ8 with stock engine (but Getrag gearbox) but
> Mallory distributor without vacuum advance. When he runs the car between
> 2,000 and 2,500 rpm and starts to slightly accelerate his engine starts to
> misfire. It feels like as if someone switches off ignition for a split
> second and the car misfires.
> 
> There's no problem running the car in either speeds below 2,000 rpm or above
> 2,500 rpm, full acceleration, steady speed or deceleration. He had his carbs
> adjusted and synchronized but this did not change the situation.
> 
> Yesterday we put a new coil (high performance) in. This made the problem
> even worse. Afterwards we exchanged the Mallory distributor against an
> electronic ignition (123ignition), but forgot to connect the vacuum line on
> our first test ride (vacuum line blocked by a screw). The ignition misses
> were still there but they were not as bad as on the test drive with the
> Mallory. On our last test drive we had the vaccum hose connected and we
> nearly had no miss anymore. On his drive back home (2 hours drive) he still
> had some few ignition misses, but not as many as with the old setup.
> 
> His ignition cables are new and look good. Does anybody has an idea what
> these misses can be caused by?
> 
> Thank you.
> 
> Eric
> Heinsberg/Germany