count a +1 tooth rather than a -1

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ochizon
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count a +1 tooth rather than a -1

Post by ochizon »

I am VERY slow in figuring out this whole timing thing, but am slowly coming around. I have a 36 + 1 (35 teeth, plus 1 double wide tooth) wheel at the crank. All I see reference to in the megamanual are -1 teeth. Is this an issue, or will is read the wheel the same? Basically, can I use this wheel?

BTW, its a 4 cyl even fire w/ distributor.
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count a +1 tooth rather than a -1

Post by Keithg »

a picture or sketch would be helpful. I think I may understand what it looks like. I do not know how a VR sensor would deal, but a hall sensor could be wired in a 'schematic 1' form in order to get a 36-1 pattern to MS.

KeithG

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ochizon
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Post by ochizon »

it is a hall effect sensor that is wired up stock.
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Post by Keithg »

Well, all I can say is try it.

See if the hall goes low when a tooth is present. If so, use Schematic 1. You will probably need a 1k pullup on the hall sensor to check this. Try using the 'schematic 1' from the MSnS-E page. If it soes not seem right, use schematic 2. The ones lower on the page are a bit easier to understand and read.

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Post by boost junkie »

Actually, it will probably work. The code simply checks gap in the irq times. A long tooth will have the same time gap between irq's as a missing tooth.
ares650
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Post by ares650 »

Keithg wrote:Well, all I can say is try it.

See if the hall goes low when a tooth is present. If so, use Schematic 1. You will probably need a 1k pullup on the hall sensor to check this. Try using the 'schematic 1' from the MSnS-E page. If it soes not seem right, use schematic 2. The ones lower on the page are a bit easier to understand and read.

KeithG
Which Schematic do you mean. This is on a toyota pickup with a 2rz, right?
Keithg
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count a +1 tooth rather than a -1

Post by Keithg »

I know nothing about toyotas, but on the msns-e page for hall trigger information, there are 2 schematics, 1 and 2.

http://megasquirt.sourceforge.net/extra/setup-msns.html

KeithG

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ares650
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Post by ares650 »

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Post by Keithg »

yeah, but that pagr mentions nothing about hall sensor input connections.

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Post by boost junkie »

The neon uses a hall sensor. The neon setup page on the MSnS-E site explains how to modify the input circuit. Might work for your application...
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