02-16-2014, 02:28 PM
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CC Member
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Join Date: Apr 2012
Location: Bay Area (Peninsula),
CA
Cobra Make, Engine: ERA 427, 427/487 side-oiler
Posts: 1,248
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Not Ranked
Stewart Warner tach problem
My first start and drive of ERA 797 have gone surprisingly well. But the two outstanding items I have are a non-operatational tach and speedo.
The SW tachs are supposed to work with the MSD ignition modules without the MSD adapter you need for some of the tachs. I used a digital Fluke meter set to DCV and measured the tach output wires at the connector under the hood, and at the tach itself. I get the same results: power = 14v, trigger = approx. 7v. I understand the trigger is a 12v square wave with a 25 degree duty cycle, so that is why I may be getting a different trigger reading. But I do appear to have adequate voltage for both connections - neither are zero. I have a hard time believing the tach is dead and usually default to assuming that I screwed something up (an assumption that mostly is correct).
Any idea what might be the issue, or if there is anything else I could check?
Last edited by lippy; 02-16-2014 at 03:56 PM..
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Linear Mode
