[Healeys] Car dies suddenly

[Michael Salter]

Hi Michael,
100's do have the master switch grounding wire to the master switch so it
might well be worth checking.
The symptoms sound very similar to those I encountered with a faulty coil.
Mine would run for about 30 minutes fairly consistently before suddenly
dying.
Even when the engine would not start the bad coil still produced a
significant spark each time the open points were shorted with a screwdriver
which I at the time, mistakenly,  felt confirmed that the coil was actually
okay ... it wasn't.
I was only able to confirm that the villain was in fact the coil by
installing a replacement.
I have encountered very similar symptoms with a faulty condenser which was
confirmed by spraying it sparingly with ether to cool it down and then
finding that the engine started immediately.
As I'm sure you are aware a fuel delivery problem never causes the engine
to stop dead ... it typically sort of peters out!!
 I would recommend trying the condenser trick and then, if a regular coil
can be used as a substitute for the Mallory try a substitution.

M

I wonder where the term "peters out" comes from ... Google time.


On Wed, Mar 20, 2019 at 2:13 PM <simon.lachlan at alexarevel.plus.com> wrote:

> I’m presuming that the car’s a 100? You make reference to 4 plugs…..
>
> Do 100s have the dreaded white wire from the on/off switch in the boot? Do
> 100s have the switch even? Anyhow, that wire shorting out has caused
> endless tears.
>
> Or is it a black/white wire?
>
> Worth a look.
>
> Simon
>
>
>
> *From:* Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Michael
> Oritt
> *Sent:* 19 March 2019 17:46
> *To:* Austin Healey <healeys at autox.team.net>
> *Subject:* [Healeys] Car dies suddenly
>
>
>
> Yesterday morning I went out for a drive and after about five miles the
> car suddenly died. There was no rough running, sputtering or missing
> leading up to it—the car simply died. I coasted to the side of the road and
> after about 30 seconds since the key was still on I pushed the start
> button. To my surprise the car started immediately, revved freely and idled
> smoothly. A bit perplexed I decided to drive on to see what would happen
> now that I was paying close attention. The car accelerated smoothly and ran
> fine for about 1/2 mile and then it died again in the same manner as
> earlier. I shut off the key, popped the hood and examined the ignition
> system. Everything seemed fine—all spark plug leads were firmly in place as
> was the lead from the coil to the distributor. The power wires to the coil
> were tight and the harness/connector to the distributor (see below) seemed
> fine.
>
>
> After scratching my head for a couple of minutes I got in the car, turned
> on the ignition and pushed the start button. Again, the car started right
> up and ran normally. With fingers crossed I headed for my shop/garage,
> about ten miles away and got there without any further event. Though the
> problem did not seem to be fuel related I decided to verify that this was
> not a fuel delivery issue. I have a double-headed SU fuel pump wired to a
> switch mounted just behind the driver’s seat which allows me to switch
> between pumps as well as turn the fuel pump off. While I was running the
> car at highway speeds it ran perfectly on either pump and when I selected
> the “off” position it slowly lost power as I expected it to—but in no way
> like it had suddenly twice died 15 or so minutes earlier. This indicated I
> was not dealing with a fuel issue but rather something related either to
> the ignition system or to the primary wires that run to it.
>
>
> This morning I dove a bit deeper to try and diagnose the problem. The car
> has a Mallory Unilite ignition system tied to an MSD coil which has been in
> place and performed faultlessly for a number of years. I removed the
> distributor cap and everything appears to be okay, at least visually. The
> interior of the distributor was clean and dry as was the cap, leads, carbon
> contact, optical reader, etc. Mallory specifies the use of a ballast
> resistor in the lead from the power source to the coil and with the engine
> fast-idling I tested 12.5 VDC to the resistor and about 5.5-6 VDC out of it
> and at the positive coil terminal.
>
>
> I have a large low-oil pressure light that is mounted in the dash in place
> of the original overdrive switch. It is wired from the ignition switch
> through a 10 psi normally-closed switch mounted in the oil pressure gauge
> sender line and then to the light. I point this out because both times when
> the engine shut down yesterday the light immediately came on, from which I
> conclude that the ignition switch itself is not the source of the problem.
> And though I did not remove the ignition key switch the wires to and from
> it seem tight and intact.
>
>
> So my question is: What do I do? I hate to throw parts at it without
> finding something that appears to be defective but I don’t know where to
> start any further tests, etc. I also don’t want to simply wait for the
> issue to happen again. BTW over the weekend I drove about 150 miles with no
> issues whatever. Beyond installing four new plugs last week I have not
> performed any work related to the ignition system. All
> suggestions/questions welcome….
>
>
>
> Best--Michael Oritt, BN1
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