Hall effect testing
Thread Starter
Drifting
Joined: Jun 2012
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Hall effect testing
I was going to test my HEI hall effect but i noticed it only has 2 wires, green and orange. Most have 3, plus, minus and signal. For some reason i cant find the hei wiring in the schematic. Any of you guys tested one? I assume they are using the hei body as the hall effect ground.
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Unless you've got something other than an ordinary HEI/EST distributor, the pickup coil is a VR (variable reluctance). Two wires, AC signal.
Tech Contributor
Joined: Jun 2004
Posts: 20,850
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
As I said earlier, they great majority of HEI/EST distributors have a VR sensor in them, not a Hall sensor. Can you post a picture of your particular distributor so that we're all on the same page?
Thread Starter
Drifting
Joined: Jun 2012
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Test
I put a vom on the unplugged coil and read .5 volt. So the 7 pin module must be an amp. Its even heat sinked. Whats interesting is i tested a few hei's i have and they all tested different, mostly lower voltages like .05.
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
The pickup coil only generates a voltage when the distributor/reluctor wheel is turning. That's how a VR sensor works. The 7TM processes the AC signal from the VR sensor and outputs a square wave signal to the ECM for timing and RPM calculations. The 7TM internal power transistor switches the coil primary current on and off, using the EST timing signal from the ECM during normal run mode, and its internal timing signal during cranking and ECM-failure modes.
