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sam_w
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Joined: March 07, 2002
Posts: 1479
Location: Petaluma, CA
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 Posted: Sun Jul 17, 2016 5:52 pm Post subject: Vdo tach reads 50% high |
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I have a pre dip switch vdo tach in my 63 single cab. The tach reads 4500 RPM when doing 3000 RPM. it has no dipswitches, I am told there is a jumper to cut. There is a number, 14000 on the back. Anyone got ideas?
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rugblaster
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Joined: March 31, 2016
Posts: 1170
Location: San Angelo, Texas
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| Posted: Sun Jul 17, 2016 6:52 pm Post subject: Re: Vdo tach reads 50% high |
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I think you can put a diode on the wire going to the coil negative...and it may have a potentiometer that has to be adjusted..........maybe VDO knows.
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Last edited by rugblaster on Mon Jul 18, 2016 12:26 pm; edited 1 time in total |
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vwracerdave
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Joined: November 11, 2004
Posts: 15302
Location: Deep in the 405
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| Posted: Sun Jul 17, 2016 8:28 pm Post subject: Re: Vdo tach reads 50% high |
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Yes some of the VDO universal tachs had a little pigtail loop wire that you cut one color for 6 cylinders and another color for 4 cylinders or maybe both colors. Look for a model number on the face of the tach.
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Dale M.
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Joined: April 12, 2006
Posts: 20377
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Sun Jul 17, 2016 8:40 pm Post subject: Re: Vdo tach reads 50% high |
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Cutting loops was pretty common on tachs before dip switches...
Dale
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