Classic Mustangs List Archive

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Mail From: 69stang11 (Eric Haack)

Note: If you are using a CD ignition box, you must bypass it before
performing this test.

1) Remove the cap and rotor. Turn the ignition ON and test voltage at the
NEGATIVE side of the coil (black lead of meter to ground and red lead of
meter to coil NEGATIVE post). Voltage should read 12 volts.

2) If battery voltage is present, place a credit card, driver's license,
business card or similar and block the photo optics of the module. The
voltage should drop to 2 volts or less (1 to 2 volts is sufficient). If this
test is positive, then module is working.

3) If the test results are as follows;
a) Voltage does not drop, module is open and must be replaced. This may
have been caused by a power surge, high resistance in the plugs or plug
wires, or improper ground. Possible charging system load dump.

b) Voltage ALWAYS stays below 2.0 volts. The module has been spiked by
high voltage or amperage, lack of ballast resistor, or improperly wired.

c) Voltage only drops to 3-4 volts could produce a weak spark.

Possible causes are;

Faulty charging system (stuck or shorted regulator/alternator).
Faulty starting system. (starter drag)
Non suppression spark plug wires (copper or stainless core wires). Spark
plug wires must be carbon core or spiral wound plug wires.
Large amperage alternator.
High amp stereo equipment
CB radio
Direct shorts in the ignition or electrical system
Trying to start motor with battery charger hooked up........I'm guilty and
did loose the module. Ooops!! :-(
Welding on the vehicle with distributor hooked up (disconnect 3-wire plug
of the distributor before welding)
Faulty or improper ground of module.

If you must replace the module, replace it with Mallory Part # 605.
If after completing the test and you are not sure of the results,
216-688-8300 Ext 5

I'm assuming that's Mallory's phone #. I live only 14 miles from the plant
in Carson City. Unfortunately I cannot buy my parts there. I must drive to
Reno and go to Summit Racing. Only 1 1/2 hours away. Talk about a kid in a
candy store!!

Eric
69 Sportsroof




----- Original Message -----
From: "Paul Sawyer" <PSAWYER at i-55.com>
To: "Eric" <69stang11 at charter.net>
Sent: Wednesday, September 26, 2007 5:51 PM
Subject: Re: [CM] It Continues, Clarification


> E--
>
> How long does one of these last? Ours is about 16 years old,
> possibly older.
>
> -P
>
> On Sep 26, 2007, at 4:12 PM, Eric Haack wrote:
>
>> Are you running an electronic ignition? I had the exact same
>> problem when my
>> Mallory Unilite was going out. An occasional backfire and ran rough,
>> although she did have her good moments. Replaced module, ($90.00
>> later), and
>> she ran great!
>>
>> Eric
>> 69 Sportsroof
>>
>
> _______________________________________________
> Classic-mustangs mailing list
> Classic-mustangs at lists.twistedpair.ca
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>
> Visit the Classic Mustang Wiki! sauce.donair.org/~cm/
>

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Mail From: PSAWYER (Paul Sawyer)

Hi all--

The solution to the problem we pounded out last week was the module.
Turns out, the original module had been in there so long, the rotor
had cut a nice trough through the Mallory Decal! Got some weird
voltage readings on the older one, so I found a new one at a local
speed shop (Thanks Claussen Racing!) and swapped it out. Purrs like
a kitten and took it on a 35 mile trip through town to see if it
behaved. No problems at all. I'll drive it the rest of the week to
make sure it continues to behave before we head out of state.

I'm sold on Mallory. It really was two small screws and threading
three wires through a grommet. Can't beat that.

Anyway, thanks to everyone who offered suggestions. Now, a quick
tune up before crusing the coast! (And I don't have to be in the
middle of 10K muscle cars/street rods in the wife's Passat. Wheh!)

8)

--P