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Thunderbolt IV ICM Conversion
I posted the following at iboats and was referred to this site for potential answer.
I have recently run into the issue of a bad Ignition Control Module on my 1996 5.7L Mercuiser Alpha drive. I have looked for a replacement and see that I can purchase them for around $450 which is so absurd that I can't bring myself to pay it. I have looked at converting to a Delco EST system which can be purchased for around $250 for aftermarket manufacturers on Ebay. I really would like to see if anyone has attempted to install the EST ICM on a thunderbolt distributor. The EST module has the timing curves set for the mercruiser and it is marine rated. I would think that it would only be a matter of making a pigtail to wire it into the system. I do not know if the hall effect sensor would be suitable for input or if the coil would have any issue but otherwise it should work. I would appreciate any input from others that may have attempted this or have pertinent information on the subject. |
If you are going to use the EST you will need the complete setup using the EST distributor & coil. You also need to hook up the shift interupt
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Are you just needing the the thunderbolt IV module? I have a good V8-20r module and coil siting on the shelf I would sell.
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Hall Effect and Magnetic Trigger both use magnets...but in a different way. I do not see a GM module working in it's place.
You would need a converter of sorts...like some ECU's will have to be flexible with different trigger input types. Here's a good quick summary: A magnetic pick up will use two wires, with either a rotating metal component inducing an a.c. voltage (sine wave) in a fixed coil of wire surrounding a magnet (basic electronic ignition pick up) or a moving magnet inducing a voltage in a fixed coil of wire (think of an MSD crank trigger). A hall effect (three wire) usually uses a blade to change a magnetic field, causing an A.C. voltage which triggers a transistor. This transistor will toggle a supplied voltage (usually 5v on automotive computers) to go from 0v to 5v in a square wave output. A digital (square) signal is more precise because its either on or off, no guesswork. |
Thanks for all of the input. I have picked up a module for very little and will do some experimenting. My concern, as SB pointed out, is the signal from the hall sensor vs the signal from the magnetic trigger. I think the hall sensor will give more of a square wave and the magnetic pickup will be more of a spike. I will try to get an EST distributor and compare the signals on an O-scope.
wfo, Thanks for the offer. You can PM me with the price that you would want for the module. Although I like a good project and it would be helpful to all if we could find a more economical solution to the thunderbolt ICM problem. |
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