Why upgrade my engine's ignition?
The Magnavox (Type I) ignition system found on most 1988-1991 GM 3800 v6 engines works fine, most of the time. The Magnavox system was replaced with the Delco (Type II) system around 1992. One benefit of the later Delco system is that it consists of three individual coils, unlike the large single unit of the Magnavox. This makes it easier to find and replace failed coils. Delco systems also seem to be less troublesome, and produce stronger spark.
It's easy to tell if you have the Magnavox ignition. Visually, the Magnavox can be identified as having three spark plug wire terminals on each side, while the Delco system has all six terminals on one side. Also, the Delco has three individual coils (as mentioned above), while the Magnavox has one coil unit.
Fortunately for those of us who were given Magnavox from the factory, the Delco units are a bolt-on replacement!
Finding the right parts
First off, what you need:
- Three generic GM coil units (these are used in so many cars... mine were from a Lumina 3.1)
- One Ignition Control Module (ICM) from a 3800 with the Delco setup ('91ish - current). This MUST be from a 3800 for it to work.
- One metal plate which goes beneath the ICM, from any N/A Series I 3800 with the Delco system, NOT a Series II (they used a different bracket). The SC engines may have the same bracket, but I am not sure. Also some 3300 engines supposedly have it. You'll know it when you see it.
- Six screws to mount the coils and ICM to the metal plate
- Three special square headed bolts to mount the metal plate to your engine
I got my coils for $8 on Ebay, shipped. I got the ICM, metal plate, and screws off Ebay as well, for $18.50 shipped. If you watch and wait, you can get them for pretty cheap!
The coils found on a supercharged 3800 (L67) are supposed to be more powerful than the other generic GM coils. These will be harder to find, but could possibly perform slightly better.
It is best to stay away from any aftermarket replacement coils. They are not as good as the stock GM coils, and tend to fail quickly. They will look similar to GM coils, but will not be numbered, and are sometimes different colors, and slightly different in shape. The exception to this rule would be a high-performance replacement coil from MSD, or similar.
Time to start wrenching
So here's what you should have:
And upside down:
Go ahead and assemble all of that. Don't forget to have those three square-headed bolts sticking out of the bottom BEFORE you attach everything else, or you'll have to take it all back apart.
Then, take the old Magnavox unit off your car. I believe that I used an 11mm for the nuts holding it on. Two of the three are easy to get to, but to get to the front one closest to the head, I had to loosen the nut holding on the ground wire from the head to give me room to move the wires so that I could actually get a socket on there. I believe that I used a 3/4" deep there. Later, I had to remove the nut entirely, but more on that later.
Once you've got the nuts off, remove the wiring harness from the ICM. Note that it is attached with a small integrated bolt. It won't come out of the connector, but must be loosened to allow the connector to come off. I don't recall the size off hand...
Looking at both units, you will see that they mount exactly the same.
One thing that I did notice was that the old unit had one more pin on the connector than the new one does! Looking at the wiring harness on the car however, it apparently isn't used.
This is what the engine bracket looks like empty...
When I went to actually mount the new unit, I first tried to attach the wiring harness to the unit and test fit it. The harness was too short. What I did to fix this was to remove the short ground wires from the stud on the head (as previously mentioned), and un-twist them a little to give me more slack. Then I reattached them. It's still a bit snug, but it works. Then I tightened up the connector, bolted the coil/ICM unit on, and tightened up the nut holding on the ground wires.
You're almost there. Now you've just got to route your plug wires somewhat creatively. The 2-4-6 wires from the rear bank are easy, but you'll have lots of slack in the front 1-3-5 wires due to the fact that they were sized to run to the other side of the coil. I have mine set up so that they curve up, over the valve cover, and back to the coil. You might have to undo some clips to give you some slack, etc. Ideally, you should buy a replacement set of wires made for a '93 or'94, since they will be the right length.
Here's what mine looks like now:
End results and thoughts
I think I can tell a slight difference with the new ignition. The engine seems to have a little more power than it did before. I keep the old one around as a spare, and for troubleshooting.
Additional reading
- Padgett's Page - http://6007.us