Ignition Control Module

[parsok]

Sorry if this is a dumb question but... what EXACTLY does the ignition control module (located under the coil) do?

Would it have any impact on the smoothness (techie term) of the engine?

[djape1977]

no. it either works or it doesn't

[So Cal Mark]

it's an amplifier for the pick up coil signal

[wikkid]

AutoZone actually had one >>>>> IN STOCK! when I went in there. Also, however, they had the diagnostic equipment to test mine, and found it to be fine.

[aj81spider]

Here's how I understand it works (as an electrical engineer, not a car guy). The coil is basically a transformer. That means it will transfer power (and amplify voltage) on current changes in the primary side. To induce a large voltage on the secondary side the primary is connected to 12 volts, the magnetic field builds, then the current is interrupted. The interruption/change causes the field to collapse and that change in field induces a voltage on the secondary in proportion to the winding ratio.

On an older Fiat the interruption of current through the primary is caused by the points and the resulting voltage on the secondary is distributed through the distributor to the appropriate cylinder. On a newer Fiat a signal is sent from a magnetic pickup to the Ignition Control Module. The Ingnition Control Module is basically a set of transistors that interrupts the flow of current on the primary side (think of it like a set of points opening up). It has two advantages over points. The timing can be controlled very precisely (although limited by the accuracy of the magnetic pickup), and it doesn't wear out because a spark is eroding two pieces of metal.

[parsok]

Gents, thank you very much for the info, much appreciated.

[parsok]

is there a way to test the ICM to tell if it works?

[ga.spyder]

I just wanted to interject that the module is a stock 4 pin GM part,and is avaiable cheap from any parts store.Accel makes one that is supposed to increase performance.I bought one and put in on,and I could tell no difference whatsoever.I got my money back after it quit working at all!!

[wikkid]

is there a way to test the ICM to tell if it works?

Yes: See my first post, a few above your question.