Anybody got any tips on how to prevent the ignition control module from barfing its gooey innards?

I'm planning some upgrades in a few weeks and also detail the engine compartment. I cleaned it up once and resealed it with RTV but it barfed again last summer. I've been carrying a spare ICM since electronics tend to generate more heat before they die.

I've been thinking of fabbing up a cold air housing for it and using a computer power supply blower motor to draw external air over the heat sink. Whaddya think? Overkill or OCD?

 

Some guys mount the ICM on a stack of washers to promote better air flow and dissipate heat, some go as far as to drill holes in the inner fender under the ICM, but your idea would definitely take cooling tricks to the next level.

Are you running Motorcraft ICM's or the local parts house generic versions? i've never had a Motorcraft module overheat and melt on me, though i can't say that about the other brands (most are reverse engineered modules from China and/or Taiwan).

 

I'm curios what the internals of the box are like, and wonder what part in them always fails.

 

The inside of the ignition module is a circuit board. On that circuit board is a high-power Darlington-pair transistor. Its surface area is less than one square inch in most cases. This transistor is analogous to the points in a breaker-point setup. The transistor is heat-sunk to the exterior of the ignition module (meaning the circuit board is upside down when installed in the truck). The underside of the ignition module is then filled with conformal coating to completely seal it from moisture. In other words, the metal part of the module is used to dissipate heat; the underside is used to seal it. The rest of the circuit board is populated with smaller components used to manage the drive circuit into the power transistor. Any of these components are subject to fail over the length of time they are exposed to intense heat.

Here are the top three ways to preserve the ignition module:

1) Ensure proper heat sinking between the mounting flange and the fender well, to help spread heat from the case to the rest of the sheetmetal. In other words, make sure it's snug, don't mount it to plastic, etc.

2) It can help to "raise" the module with washers to allow airflow underneath. This can be done while still maintaining my point above.

3) Don't use foreign reverse-engineered modules from places like Autozone. Pay the $80 for a Motorcraft unit. It will pay for itself after a few years.

If anyone's interested, here is some more detailed information on a common type of ignition module transistor: http://www.st.com/internet/com/TECHN...CD00000007.pdf

 

Ok, that makes sense. Reps sent

 

The melted ICM (currently installed) is a Motorcraft. My spare is a Wells which checked out four-oh before stowing in the spares box.

Okay, so the trick is airflow and air circulation rather than extreme internal heat before it goes bad. I'll re-seal it again and fab up a bracket to mount it horizontal with air holes underneath. I'll fab up a cold air system down the road if needed if warranted...

 

I've seen a melted ICM from a 90 7.3 diesel and 460's with dual 950 amp batteries but not on single battery systems and was under the impression this was caused either by bad battery grounding or to much amperage.Make sure your solinoid is clean and grounded. Just an idea, probably wrong but food for thought if this is a repeat problem. Good idea about the washers, drilling holes makes me fear future problems with moisture and dirt. .2 cnts.

 

I mounted mine on my old truck using vibration mounts. I think they are from MSD. You can buy them from summit or jegs. They space the module out from the fender about 3/4"

Never had any problems after doing that.

 

DuraSpark electronic ignition introduced in 1974, but not all vehicles came with it until 1976. Module used in 1974 is 1974 only. Module used in 1975 is 1975 only.

I've never seen a melted ignition module, which on 1974/86 F100/350's, is located on the left fender inner apron, just in front of the firewall.

The modules used in the 1970's were so unreliable, that Ford techs referred to them as NeverSpark!

Engine heat is the mortal enemy of these modules which overheat, causing the engine to die. Within a short time after this first occurs, the module overheats, BURNS OUT. Now the engine will not restart.

Taking it to an autoparts store to be tested: Will test OK unless the little charmer has burned out. When replacing, use some washers to space it further away from the apron, the more airflow, the better.

Modules are identified by a colored plastic square above where the wires feed out. The most common module used 1976/90's (except some CA vehicles) has a blue plastic square.

If a red plastic square, STAY AWAY, it was a POS from day one, I kid you not! Installed in some 1977/79 sold new in CA vehicles only.

1U2Z-12A199-AA (replaced D6AZ-12A199-A, D8VZ-12A199-A & D9VZ-12A199-A) .. Ignition Module ~ blue plastic square (Motorcraft DY-893).

MSRP: $120.84 / FTE sponsor tousleyfordparts.com price: $73.11 (MN) / FTE sponsor silverstatefordparts.com price: $78.42 (Gaudin Ford-Las Vegas) / FTE sponsor horizonpartsguy.com price: $79.75 (Tukwila/Seattle WA)

 

... for anyone wondering, by deduction my rig has a 73 cab on what is otherwise is a 74 frame, bed, drivetrain, etc/ so it has a DS ignition system. The ICM has a black grommet.

 

I noticed 1973 F100 below avatar, why I said DuraSpark intro'd in 1974. Black grommet is either 1974 or 1975, cannot recall which. While not the POS like the red module, both were problematic and are obsolete.

1974: Will have D4AE ID number prefixes (Motorcraft DY-157-B) / 1975 will have D5AE ID number prefixes (Motorcraft DY-166-B).

 

Black grommet = '74

Green grommet = '75

(As already noted, both are one year only modules)

 

My 75 has the green grommet which I've heard that green will only work with green and no other will work. Anyway, I've never seen one melted, but I'll have to remember these tips on mounting and try to find a motorcraft instead of the crappy aftermarket ones. IDK what I have in there now, I'll have to look.

 

I'm just going by what my title says it is... legalities vs realities.

I totally scared the kid who sold it to me when, among other things, I decoded the VIN and pointed out the DS system. He knocked more off his asking price to the point where I basically bought a set of new tires with an attached 4x4.

 

If the module has already bled out, it needs to be replaced. I don't know how to tell if RTV is a proper replacement for the coating installed by the factory, and if it's worth re-sealing if it has already been exposed to open air and moisture. More importantly, there's no way to tell if the coating bled out because it got old, or the module overheated (and is close to failure).