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Does anyone know what the ac output voltage of an msd pro billet magnetic pickup should be. I am suspicious that the pickup may be the source of the random misfire I am getting. Everything else in my system checks out. I am measuring 596 ohms between the two wires of the pickup but only .68 volts ac when the distributor spins. I thought this pickup should put out more voltage. Does anyone know what ac voltage the pickup should generate? MSD tech line was not much help. Only gave an ohm value.
 

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Discussion Starter #3
Thanks. I’ll have to look elsewhere in my system. Maybe a shielded cable for the pickup wires will help.
 

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Does anyone know what the ac output voltage of an msd pro billet magnetic pickup should be. I am suspicious that the pickup may be the source of the random misfire I am getting. Everything else in my system checks out. I am measuring 596 ohms between the two wires of the pickup but only .68 volts ac when the distributor spins. I thought this pickup should put out more voltage. Does anyone know what ac voltage the pickup should generate? MSD tech line was not much help. Only gave an ohm value.
The pickup coil signal voltage varies with RPM (low voltage at cranking speeds, and high(er) voltage at high RPMs), and also depending on the air gap width and the module input resistance.
 

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PLEASE, post specs if you are going to be vague.

MSD 8466-1 magnetic pickup info:

Manufacturer: Standard Motor Parts
Origin: Ford, 1976-on Dura-Spark systems
Primary resistance: 400 to 1,100 ohms
Spinning output (idle to maximum rpm's): .050 to .075 DC volts (this is NOT specific to rpm levels, but for the actual pickup construction)
Air gap: between .010 to .040 inch distances, NO variance within those parameters, but loss of signal can occur when gap exceeds .040 inch
Output is considered stable and strong at the listed voltage output levels, and those values vary from pickup to pickup

Module performance levels have NO influence on the magnetic pickup signal, NONE, the pickup either works, or it isn't set up right, and DOESN'T work at all
 

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PLEASE, post specs if you are going to be vague.

MSD 8466-1 magnetic pickup info:

Manufacturer: Standard Motor Parts
Origin: Ford, 1976-on Dura-Spark systems
Primary resistance: 400 to 1,100 ohms
Spinning output (idle to maximum rpm's): .050 to .075 DC volts (this is NOT specific to rpm levels, but for the actual pickup construction)
Air gap: between .010 to .040 inch distances, NO variance within those parameters, but loss of signal can occur when gap exceeds .040 inch
Output is considered stable and strong at the listed voltage output levels, and those values vary from pickup to pickup

Module performance levels have NO influence on the magnetic pickup signal, NONE, the pickup either works, or it isn't set up right, and DOESN'T work at all
Got a link to where you got those numbers?
 

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Yeah, Mr. Know It All , MY VERY ACCURATE VOLT METER, and more than a frw others belonging to other people.

Post YOUR HANDS-ON readings, NOT copy & Paste, smart guy.

Please remember, when you attack me on things, especially ignition systems, I WORK IN THE IGNITION SYSTEM INDUSTRY, also did same for GM, and a lot of other companies along my 40 plus years in it.
 

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PLEASE, post specs if you are going to be vague.

MSD 8466-1 magnetic pickup info:

Manufacturer: Standard Motor Parts
Origin: Ford, 1976-on Dura-Spark systems
Primary resistance: 400 to 1,100 ohms
Spinning output (idle to maximum rpm's): .050 to .075 DC volts (this is NOT specific to rpm levels, but for the actual pickup construction)
Air gap: between .010 to .040 inch distances, NO variance within those parameters, but loss of signal can occur when gap exceeds .040 inch
Output is considered stable and strong at the listed voltage output levels, and those values vary from pickup to pickup

Module performance levels have NO influence on the magnetic pickup signal, NONE, the pickup either works, or it isn't set up right, and DOESN'T work at all
Got a link to where you got those numbers?
Yeah, Mr. Know It All , MY VERY ACCURATE VOLT METER, and more than a frw others belonging to other people.

Post YOUR HANDS-ON readings, NOT copy & Paste, smart guy.

Please remember, when you attack me on things, especially ignition systems, I WORK IN THE IGNITION SYSTEM INDUSTRY, also did same for GM, and a lot of other companies along my 40 plus years in it.
:)

Holy Smokes.
I am interested in this also and I didn't take it that he was being a know it all.
He was asking for link. But, if you did the research yourself,
there shouldn't be an issue with just stating that. I for one
appreciate the fact that you share the information with us.

Healthy debate helps everyone learn, there is no reason it all
can't be done in a civilized manner.

When publishing written research articles there is a reason they under go peer review.
It's a very humbling experience. Some cannot bare it and only do it once.

It also never hurts to have a bibliography/reference list etc, even if it references
your own work logs.

It's all good if we keep learning and moving forward and don't fall into

-- Spike
 

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Yeah, Mr. Know It All , MY VERY ACCURATE VOLT METER, and more than a frw others belonging to other people.

Post YOUR HANDS-ON readings, NOT copy & Paste, smart guy.

Please remember, when you attack me on things, especially ignition systems, I WORK IN THE IGNITION SYSTEM INDUSTRY, also did same for GM, and a lot of other companies along my 40 plus years in it.
Honestly Dave, do you get some kind of royalty or post count bonus for every time you mention GM? So what? I've got decades myself at GM, in ignition module and ECM/PCM design. So how 'bout saving some future bandwidth, and just assume everybody here has the mental capacity to remember that we've handled a few distributors in our time.

I stand by my earlier post (#4 IIRC). With the exception of one engine model (Buick DIS), every other program I worked on used a variable reluctance (magnetic pickup) sensor. As I stated earlier, the output signal magnitude varies depending on the air gap width (larger voltage with smaller gap) and the RPM (the signal waveform increases in magnitude as the RPM goes up). A simple google search will show the typical VR (variable reluctance) waveform at different engine speeds and tooth gap sizes. These waveforms are correctly measured with an oscilloscope, not a voltmeter. And the VR signal is affected by the loading (input resistance) of the module. The energy output of a VR sensor is low, and that's why the input resistance of ignition modules needs to be high, so as to not load down the VR signal magnitude.

That's the facts, and my experience from a lotta years designing engine control modules. And as Spike mentioned (peer reviews), I've spent my share of time in them, explaining my designs to a room full of very smart guys. It's not fun, but it's a helluva efficient method of persuading every design guy to check his work ten times over before submitting it to management for peer review and production.
 
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