MS3 knock sensor wiring question.

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MS3 knock sensor wiring question.

Postby GeorgePatches » Sun Dec 17, 2017 5:12 pm

I'm setting up a 305 TBI with a MS3 and I'm planning to use ON/OFF knock control with a GM knock module as referenced in the instructions here.

http://www.msextra.com/doc/pdf/html/MS3baseV30_Hardware-1.4.pdf/MS3baseV30_Hardware-1.4-39.html

I'm not understanding if I need to build a protective circuit as referenced on the next page?

http://www.msextra.com/doc/pdf/html/MS3baseV30_Hardware-1.4.pdf/MS3baseV30_Hardware-1.4-40.html

Or if I need some other kind of protective circuit for use with the GM knock module or don't need a protective circuit at all?
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Re: MS3 knock sensor wiring question.

Postby KAT PWR » Tue Dec 19, 2017 1:14 pm

I haven't done an analog setup but, I would say after reading you need the protective circuit. internal mode is only if you get the knock and add-on board.
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Re: MS3 knock sensor wiring question.

Postby Matt Cramer » Wed Dec 20, 2017 8:37 am

With MS3X, you should be able to run the signal into a switched input on the MS3X and have it work fine.
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Re: MS3 knock sensor wiring question.

Postby GeorgePatches » Wed Dec 20, 2017 8:14 pm

I actually found the answer on the megamanual website for the MS2.

http://www.megamanual.com/ms2/knock.htm

The signal output is going to come in at 8-10 volts from the GM module, so I need to build that circuit with a zener diode to bring it into the 0-5 volt spec for JS4 or JS5.
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Re: MS3 knock sensor wiring question.

Postby prof315 » Thu Dec 21, 2017 3:45 am

GeorgePatches wrote:I actually found the answer on the megamanual website for the MS2.

http://www.megamanual.com/ms2/knock.htm

The signal output is going to come in at 8-10 volts from the GM module, so I need to build that circuit with a zener diode to bring it into the 0-5 volt spec for JS4 or JS5.



DO NOT USE THE MEGAMANUAL! It's obsolete and some of the info is actually wrong . Use the manuals linked at the top of the page.
Linfert Performance: Come run up front
92 Corrado 2.0L ABA and Borg Warner EFR 6258 on MS3Pro.
94 Ranger 2.3 Twin Plug on MS2
Support the developers!
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Re: MS3 knock sensor wiring question.

Postby Matt Cramer » Thu Dec 21, 2017 6:54 am

The MS3X digital inputs already have the clamping circuit installed.
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Re: MS3 knock sensor wiring question.

Postby GeorgePatches » Thu Dec 21, 2017 6:47 pm

Matt Cramer wrote:The MS3X digital inputs already have the clamping circuit installed.

I have a MS3 Base though. Is there a CPU input other than JS4 and JS5 I can use to accomplish this without a protective circuit?
prof315 wrote:
GeorgePatches wrote:I actually found the answer on the megamanual website for the MS2.

http://www.megamanual.com/ms2/knock.htm

The signal output is going to come in at 8-10 volts from the GM module, so I need to build that circuit with a zener diode to bring it into the 0-5 volt spec for JS4 or JS5.



DO NOT USE THE MEGAMANUAL! It's obsolete and some of the info is actually wrong . Use the manuals linked at the top of the page.

Well the manual at the top of the page it's not clear if I need a protective circuit, nor does it give me any details on how to configure the MS3 with the GM knock module (going high versus going low). This at least clarifies what I had questions about.
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Re: MS3 knock sensor wiring question.

Postby prof315 » Fri Dec 22, 2017 4:36 am

The schematic on page 40 ( linked in your original post) is what you need. I 'm not sure what your confusion was.
Linfert Performance: Come run up front
92 Corrado 2.0L ABA and Borg Warner EFR 6258 on MS3Pro.
94 Ranger 2.3 Twin Plug on MS2
Support the developers!
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