ICM/Coil Pack Questions

[Rawja]

My '88 has been very "miss-ey" lately. Having a '88 parts car right next to it in the garage, this morning I decided to swap-out the coil pack. Totally fixed the problem.

Now the ICM in the '88 has the green goop run-off while the parts car's ICM had a nice even coat of the goop. Looked at swapping the ICM as well but I'm unclear as to how it attaches the the mounting plate.

I've also got (somewhere) the coils to go with the Series One setup, so I could probably just pick up an ICM and go that way, though again I'm not clear on the attachment to the mount.

Looked at Padgett's site via ReattaOwner and still not sure I understand. There feels like 3 bolts (11mm maybe?) underneath, though one feels semi-obstructed by a metal line running beneath it???

Also is the runny goop'd ICM a symptom of bad coils? It doesn't seem to be an indication that the ICM has a problem as my goopey ICM is now running the car smoothly and without missing with the swapped coils.

Edited May 24, 2011 by Rawja (see edit history)

[DAVES89]

There are 3- 11mm nuts that need to be removed from the bottom of the ICM. Then everything comes off [iCM and coil pack]. On reinstall I just use two nuts as it will hold good and that last nut is too hard to get at [bTW if doing it this way is good enough for Pdgett it is good enough for me].

Now would be a good time to do the Padgett upgrade to the Delco ICM and Coils.

[wws944]

...I've also got (somewhere) the coils to go with the Series One setup, so I could probably just pick up an ICM and go that way, though again I'm not clear on the attachment to the mount.

Looked at Padgett's site via ReattaOwner and still not sure I understand. There feels like 3 bolts (11mm maybe?) underneath, though one feels semi-obstructed by a metal line running beneath it???

I think the "metal line" you are referring to is simply the metal brace. There is also a battery cable under there.

Yes, three 11mm nuts. Remove them and the whole assembly comes out. (Plus the 7mm bolt that holds the wiring plug into its socket.) It is really very easy. Most difficult part is the third nut that is above the radiator hose. No room for a socket, so use an open ended wrench.

When replacing, start with the nut above the radiator hose. That way you can tip the mounting plate a bit to make it easy to get the nut started.

[Ronnie]

I have a photo if that will help.

[wht89reatta]

BTW as you probably know you might want to scrape off any corrosion as i believe the icm is case grounded

[harry yarnell]

I thought they were 10 mm nuts.

[padgett]

That's the wrench size. I generally use a 1/4" drive with a 1" extension though sometimes remove the cable/brace first. I usually just grab one or two Delcos when in the U-Pullit so have a supply. Even have a Delco in the black car and do not know why I bought it.

[Rawja]

Thanks. Didn't realize I was feeling a tubular brace rather than a pipe or sumphin'. Well, she's runnin' good now, I'll prioritize getting the Delco ICM and adapter plate.

[Rawja]

(sigh) Well, car gave me a hiccup or two, I had the Delco adapter plate and the ICM and decided to go for it yesterday. Turned into something of a fiasco.

Borrowed an 11mm open-end from my mechanic as both my sets omitted that size. Got it out thinking I'd switch the 11mm studs from old to new. Nope, need the studs as the Magnavox ICM's studs are integrated with the unit. Then I discover that the coils need long screws. Really wanted to get it rigged, so I used a bolt to hold the plate and stole a few bolts from my '94 Trans Sport's Coils. Cobbled it together and it ran like crap. Lost all confidence so I set about getting the non-goopy ICM from the '88 parts car installed with the good Magnavox coil setup. Put that in and it still ran like crap.

I made the assumption that the plug wires' length indicated which terminal they went to, turns out the longest one (passenger side) went to the middle post and the second longest went to the top post. Set that right and she's back to normal. Should have been more careful about keeping track of the wires.

Couple of observations. I didn't look to replace the coil pack until I had the classic symptoms of coil failure, but in replacing the coil pack it cleared up some poor running characteristics that I had just chalked up to age, a little stumbly at first start-up, a tiny bit more cranking to start compared to my lower mileage Reattas and an all-around rougher idle. Just putting it out there.

So I'm going to need the 11mm studs for the adapter plate and the long coil retention bolts. Is this something I can get at Pep Boys or something or am I looking at going to a dealer? Going to a junkyard is a big production for me and paying a couple extra bucks for new bolts is not an appreciable issue.

[DAVES89]

I went to the local yard to get a coil pack and ICM. This time I took it from a Pontiac Grand Prix. The mounting plate is different, and so is how the ICM/coil pack is mounted [Different screws as you stated. I should have known better.].

I took it back to the salvage yard and went into the Buick row and took one off a Buick Park Ave, with the three screw mounting plate as illustrated in Ronnie's picture. Cleaned it up and will be installing it later today, to make sure it works properly, prior to shipping it out to a fellow forum member.

[KDirk]

Rawja,

As luck would have it, I just bought 10 of the square headed studs (no nuts, will reuse the existing ones) for a Delco ICM bracket from the dealer here. I needed them to change my 88 over to Delco from Magnavox. I had to buy 10 as that was the master package size, and they wouldn't split it and hold the rest for inventory.

If you want to PM me with a shipping address, I can get three of them out to you.

KDirk

[Guest Dan Gibbs]

Hey Folks

I have replaced the ICM and three coil packs on a 1992 3800 on my Mom's car about four years ago and I have a coupla notes for all.

The ICM bottom does ground through the mount, therefore, the first thing to check with any suspect issues is to pull the coil packs and ICM and clean any corrosion on the mount bracket surface and the bottom of the ICM.

Next, if I remember correctly, there is supposed to be a skim-coat of heatsink grease applied between the bottom of the ICM and the mount plate. The "green goop" is probably heatsink grease and is what you are seeing (all heatsink grease I deal with is white - GM may have had a different spec hence the color). The ground will still be transferred and the heatsink grease fills in any surface irregularities to ensure efficient heat transfer from the semiconductor-based ICM. The power output transistors in your home stereo and you tv deflection circuits use this same stuff to keep the parts running cool.

As far as the "green goop" leaking from the coil packs - no chance. The coil packs are electric step-up transformers. They are formed copper windings that are sealed within a very hard plastic potting compound. The coils only fail when (a) the potting cracks allowing voltage to jump between the primary and secondary windings or between winding turns, ( one of the windings develops an open circuit, or © the contacts are too corroded which creates an electrical open circuit.

Hope this helps

Dan

[NCReatta]

Dan, there are two types of coil packs that we are speaking of here.

The earlier Reattas (1988-1990) had the Magnavox coil pack standard. (see below picture)

This is what the "Green goop" would come out of.

The last year of Reattas (1991) and other '91 and up 3800s were equipped with the Delco coil packs as your mom probably had/has on her car.

These had 3 separate coils. Many Reatta owners have done the upgrade to the better, more practical and better preforming Delco coils.

Hope this clarifies some..

[Guest Dan Gibbs]

"he earlier Reattas (1988-1990) had the Magnavox coil pack standard. This is what the "Green goop" would come out of." Wow okay, so my Reatta has the goop-packs....I could obviously tell mine has the all-in-one three-pack, but I never would've guessed that they were not hard-potted internally. I guess that's what happens when you let a TV manufacturer make coil packs for autos.....Definite Oddnosity

Thanks,

Dan

[Ronnie]

The photo below will explain where the goop comes from pretty well. It is a Magnavox ICM and coil pack.

[Guest Mc_Reatta]

Do NOT use thermal grease between the base of either type of coil pack and the mounting plate or the plate and the car mount.

It is non conductive and will hinder the ability of the pack to achieve a good ground with the car. Just clean all the surfaces before assembly.

The green goo is the potting compound that was used in the ICM by Magnovox.

The pack is in two pieces with a seal around the edge to keep moisture out etc.

Heat and age can break down the potting compound and it can ooze out this seal, and or around the seal to the connector.

Ronnie's photo shows it well: