Inductive pickup questions.

[washingtonracer]

I am curious, In order for me to use an MSD box, I would need send my ecu in to be converted to Inductive pickup correct? I currently have the GM HEI setup ECU. But Isn't HEI already Inductive pickup??????

 

[Roland Black]

hey Aaron;

You should be good to go as is. Slightly different setup, but I have the stock distributor on my Sy, Crane Hi6 and FAST. It works without any special mods.

Don't confuse the inductive pickup with magnetic pickup. My 91 dist. with my GM remote coil HEI is inductive. I'm unsure just exactly which dist. you have, but hopefully the above helps.

 

[Craig Smith]

If the ECU is currently configured for HEI ignition it won't work with an MSD distributor... sorry.

As most people refer to it, inductive pickup and magnetic pickup are in fact the same thing. Most sensors, whether "hall-effect" or "inductive" are magnetic. A simple way to think of these two is that a hall-effect pickup acts as a switch and an inductive pickup acts as a microphone. The output of a hall-effect sensor simply switches between 5 (or 12) volts and 0 volts, and the control system that receives this signal triggers on the rising or falling edge of the square wave signal produced. An inductive sensor works differently than this. Like a microphone, when nothing is happening around an inductive sensor, there is no output - it just sits there at zero volts. But, as the steel lead or flying magnet passes an inductive sensor, a single sine-wave pulse is created. The control system receiving this signal will trigger on the point in the middle of the sine wave where the voltage goes from positive to negative. This is called a zero crossing detector.

Each of these signals require different control circuitry to process them, and our current ECU can only be configured for one at a time. While an HEI distributor does have an inductive sensor in it, the signal from that sensor is fed to the HEI module, which in turn creates a square-wave reference pulse that is fed back to the PCM. Since the computer is working with the info coming from the module and not the sensor itself, it will not work with the inductive signal from the MSD distributor.

 

[washingtonracer]

So are you saying HEI, though it is inductive, has a Halleffect signal????? Does this mean I could go to Coil per plug, and e the e-dist??

Also, How long is the turn around time to convert my ecu to inductive and how much?? is it possible for someone locally to be able to do it? like Blood Enterprises? They sell/install the F.A.S.T. system, though are usually a good 400 bucks above anyone else's price.