Tach not reading right
Thread Starter
Instructor
Joined: Dec 2017
Posts: 108
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From: Mocksville North Carolina
Tach not reading right
I swapped out the original distributor, coil, and cap to a new Proform Chevy HEI Electronic Racing distributor kit from Jegs Part Number: 778-66941RC. As soon as I did this it threw my tachometer off. It is reading 50rpm at 70mph and I know that ain't right. What happened and how do I fix it?
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Strange, I to have a 77 and a proform distributor. my tach is working fine. did you try by passing the tach filter? just a thought.
Thread Starter
Instructor
Joined: Dec 2017
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From: Mocksville North Carolina
I did not I just plugged all the wires back where they were I didn't even notice the filter. I know that the tach read correctly before swapping. Do you think the filter went bad as soon as I swapped the distributor?
Race Director
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Ya know, I really don't know. but clearly the distributor is working or your car wouldn't be running. it's just a signal wire. not much to go wrong. just as likely your tach board decided that now was a good time to die.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
you might want to take the cover off the cap and check the wire going to the tach signal connection lug, and the lug itself. couldn't hurt.
Thread Starter
Instructor
Joined: Dec 2017
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From: Mocksville North Carolina
Well, Mother Nature isn't being too kind to me today and It looks like it will be Sunday before I can get back out there and tinker. I'm hoping it's a bad connection or the filter and not the tach itself. If It's the tach I'll be looking for a deal on a set of Dokda Digital gauges.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
Look real close at the end of the tach filter. From yrs of vibration & heat, mine gave erratic readings also. Close examination showed only a couple strands of wire were attached. You may have to remove the filter, place in a vise and re-solder the wire.
