 Save Your Mallory Ignition Module by Preventing Power Spikes and Surges
 If you happened to have already read our article on testing the Mallory Unilite and E-Spark modules you now know that most module failures are caused by other electrical components on your vehicle. Charging system components and inefficient grounding are the two most common culprits. I will also mention a few components that are available that you can purchase and install to avert some problems.
If you are one of the unlucky few that experience repeated module failures, you really need to take the time to find the true cause. That requires a thorough diagnosis of your electrical system. You need a bit of experience, a few basic tools, and knowledge of various vehicle systems to proceed with a valid diagnosis. In this article we will provide you with some basic knowledge, probably enough to confuse you or get you into trouble. But, this article is going to help you. Please make sure you read the entire article. If you call for support and an answer was plainly written on this page, you can expect that we are going to give you grief about it.
Vehicle Grounds:
First we'll start with the easiest items to check. I admit that there are more people than I can count whose vehicles do not have correct and adequate grounding.
In all the technological advances in the various industries, it is amazing to me that we still have 12-volt electrical systems in new cars and trucks. The 12-volt system has been overwhelmed and overloaded for about twenty years. Low voltage, high amperage systems are just not efficient. If all we had in our vehicles was a a starter, alternator, windshield wipers, lights, and a basic radio, the 12-volt system would be just fine. But we have all that plus electric everything. Seats, windows, seat heaters, digital gauges, sensors everywhere, high power stereos, computer management systems, DVD players, cell phones, and gadgetry everywhere. Because of this we have very high amperage alternators that cause system instability. The barrier of what a 12-volt system could reliably provide power to the average avutomobile passed a long time ago. The ONLY way that 12-volt systems have survived this long is because engineering has made basic components more efficient and less of a power drain. But, manufacturing quality has not stepped up with the other advances. Everyone cuts too many corners to increase bottom line profits over product reliability. Just check the recall lists if you question that statement.
To combat this power hungry dilemma, various car manufacturers have started releasing higher volt, lower amperage systems in their current vehicle offerings. A few manufacturers now utilize a 42-volt system on some of their vehicles. Though still in its infancy, the 42-volt systems may become the industry standard. The problem lies in re-engineering each electrical component on every vehicle. Since all the car manufactures bid out component development, they have been a bit overwhelmed, but more accurately they have been stalling due to high fuel costs, low new vehicle sales volumes, and various financial chaos.
The 42-volt system is not a cure all for poor engineering and cost-cutting, low-bidder manufacturing, but it is a step in the right direction.
With your 12-volt system, having adequate grounds is paramount. Most people do not know that whatever amount of energy is moving on the positive circuit of your electrical system, that it is also moving through the negative side of the system. Adding to that statistic is the demand for a cushion, or safety factor, when calculating ground cable sizing. If you add anything electrical to your vehicle you should upgrade the grounds by increasing cable size. That is why on vehicles with extensive stereo systems you will see huge ground cables that look more at home on a 100-ton crane than connecting components on your vehicle.
Cable sizing mentioned above is only part of the equation. On your typical street rod, muscle car, or restoration project you need to look at quantity of grounds. Anyone reading this should know that you have a ground cable from your battery to your engine, but do you know about all the other grounds your vehicle demands? Have you ever experienced a vehicle where the dash lighting flickered, starting was inconsistent or troublesome, or you dealt with repeated component failures? Almost all of those problems can be traced to poor grounding on the vehicle.
For starters your vehicle needs a complete grounding circuit. The basics include:
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Battery To Engine (large cable as possible, clean and secure connections)
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Battery to Body (typically a small 10-Gauge wire)
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Engine to Frame (large cable or 1" tinned metal strap)
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Engine to Body (1" tinned metal strap)
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Body to Frame (1" tinned metal strap)
To explain the above you need to understand that the engine is your largest chunk of metal and your best ground. Secondly is the frame on the vehicle, but some vehicles do not have a full frame and grounds are more critical. Corvette and boat owners should know what I'm talking about.
You cannot get a good ground for anything in the passenger compartment or body of your vehicle through rusty old body bolts or rubber impregnated motor mounts. That is why you need good ground straps connecting the various larger chunks of your vehicle together. This is one area of your vehicle where bigger is actually better. Overkill on ground cable sizing is actually recommended.
Ineffective grounds put extreme drain on your electrical components. Not having adequate grounds is just as damaging as not supplying the components with enough power. As they try to do their Jobi they have to work to hard and will be damaged and fail prematurely. This is true for all electrical components.
So in one simple statement you need to make sure you have enough grounds, the right size ground cables (overkill is OK and recommended), and that all the grounds are clean and secure. lastly, please make sure that the brown (ground wire) is connected to the engine block. Not the firewall, master cylinder, hose clamp (yeah we saw that once), or other wrong location.
Testing Electrical Components
As we explained above with the instability of 12-volt electrical systems, the charging system of your vehicle has become a major player in ignition module destruction. The first thing that you must know is that the parts stores selling rebuilt alternators and offering a lifetime warranty is a reminder of the blunt Chris Farley (may he rest in peace) quote from the movie "Tommy Boy".
"So why do they put a guarantee on the box? Because they know they sold you a guaranteed piece of shit"
The cheap parts used to assemble these units is cause for concern. If you read our article on Unilite® module testing I mentioned the customer that nuked three modules in one afternoon using two different alternators ... both new rebuilts from a nationwide chain store. Who cares about the warranty if you have to take your time, or worse pay someone else, each time the "warranted" piece of junk fails.
The bench testers in the parts stores are designed to sell electrical components and do basic tests on their replacements, but don't give enough information to see deeper problems. Plus, they do not want techs working the counters, they want salesmen. They make more money when they redirect you to the service desk. To properly test most electrical components requires a high speed oscilloscope and other specialty equipment. This is why we always suggest that if you have killed a module and are not certain as to why, it is best just to take the vehicle, or various components off the vehicle, to an actual rebuilder. If the problem is just a sticking regulator or cheap diode in your alternator, they will quickly find it, and gladly sell you better parts that will solve your problems. In most cases it as simple as an inexpensive diode, but one that is of a higher quality than what was in your alternator.
On rare applications you may find a worn out starter armature that is arcing out, sending a voltage spike through your vehicle. We have seen cracked starter solenoids cause this too.
Other Causes and Tests
There are other issues that can and will cause electrical component failures, but the most common would be an electrical short. This is when a power lead is contacting ground. On a typical electrical short you will get a blown fuse, but on many of the difficult shorts you will only get a slow power drain. It is these that are the hardest to find. Unless you're a wiz at electrical diagnosis, this is best left to someone that knows what they are doing.
Please do NOT weld on your vehicle when the 3-wire distributor connector is plugged in! Think of the amperage you are sending through your vehicle when welding on it. In fact, all electrical components (that you want to keep) should be disconnected for safety.
Older CB radios that were modified for more power can cause a power spike when the mic is keyed, but we have not seen this as a cause in more than 15 years ... about the time CB radios lost popularity.
Components for Prevention
There are a few things you can do to help prevent spikes from reaching your ignition module, but be advised that these are mere band-aids on a vehicle with severe electrical issues. Nothing beats finding and fixing the real problem.
Though not a guarantee, the Mallory Circuit Guard is the best component available to help prevent module failures. This component plugs inline on your 3-wire distributor harness and provides two features. The first is a signal filter that cleans up dirty power signal that occurs from dirty connections, or dust in the alternator. Think of this like a rabbit ear antenna on an old television set. They never give you a clean picture, but it takes away some of the snow. On your vehicle this takes away some of the peaks in a dirty signal. The second benefit is a compact, yet tough capacitor that is designed to absorb power spikes, and prevent them from getting to the module. It does absorb some spikes, but again, is not a guarantee. A decent sized spike will still get through. This is not a replacement for laziness in finding the cause of module failures. This component is inexpensive insurance to prevent module damage. Click on the link above for more details.
The Mallory Ballast Resistor is a variable ballast with a value of .75 to 1.5 Ohms. This is a heavy duty ballast that exceeds all accuracy and durability tests. You can still use the OEM resistance wire (if so equipped) or another brand ballast, but nothing matches the quality of the Mallory #MAL-700.
  Install an inline fuse to your ignition amplifier.
If you are using a Mallory Hyfire® unit on your vehicle, it is a good idea to install a fuse ... consider it insurance. This is NOT for your distributor or ignition module, it is for your Hyfire®. Add an inline fuse on the RED power lead into your Mallory Hyfire® or other aftermarket ignition unit. The fuse rating should be over the 1 Amp per 1,000 RPM draw of the unit based on engine operating speed. This is the wire that connects directly to the battery or 12-volt power supply. The fuse will cushion minor voltage and amperage variances, or the fuse will blow if there is a serious deviance in supply voltage, thereby protecting your ignition control unit. (This is funny that the ignition unit manufacturers do not tell you this, or even include a fuse in the power supply lead isn't it?) The reason you are not told this information is that the demand of the ignition unit varies under loads and RPM changes. You do not want to undervalue the fuse rating and lose needed power supply to the unit.
An Example: You have a nice engine that sees 6500 RPM shift points --- add a 10-20 Amp fuse (1-Amp times 6500 RPM is a 6.5 Amp fuse, but give yourself a bit of room). The reason for this rating is that your Mallory Hyfire® ignition unit will normally draw just under 1-Amp per 1000 RPM, but it will rise under load and requirement. If you add a 6.5 Amp fuse on a 6500 RPM engine you may blow the fuse every time you get to your shift RPM, or lose needed supply voltage to the ignition unit when the fuse heats up from supply voltage.
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