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- - Tachometer issue (https://67-72chevytrucks.com/vboard/showthread.php?t=718500)

HIGHWAY BY THE SEA

09-24-2016 10:38 AM

Tachometer issue

I just had my tach rebuilt by a professional gauge repair service and installed it. It worked fine for two weeks, but yesterday that changed. It would work for the first five minutes of drive time, then abruptly go to zero and stay there regardless of what was done to correct it. Turning off the engine for 10 to 20 minutes would allow it to work again until 5 minutes of drive time, then it would go to zero again. What the hell...? It will infuriate me if I have to uninstall this again and resend it back to the repair company. Any ideas on the issue?

gmachinz

09-24-2016 10:45 AM

Re: Tachometer issue

Are you running a tach filter w/your HEI?

HIGHWAY BY THE SEA

09-24-2016 10:55 AM

Re: Tachometer issue

Quote:

Originally Posted by gmachinz (Post 7722794)

Are you running a tach filter w/your HEI?

No. I was under the impression that this was not required.

gmachinz

09-24-2016 11:19 AM

Re: Tachometer issue

It is recommended to run a filter with any HEI GM style distributor. They were installed on GM trucks beginning in 1975. I know all of the "repro" houses for our trucks don't include them but they should-I do on mine anyway. I don't know for sure if that's your problem but it is one thing I'd be sure to do. Check the circuit board on yours for a overheated capacitor or shorted resistor.

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