Aftermarket Tach ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69C10@16 · 11-14-2007, 10:29 PM

Picked up a tach off a friend. He had it in his 88 Chevy w/a 350 all stock. It worked great. I hook it up to mine, 12V, GND, Neg on Coil, and it doesn't read at all until I rev the engine and then it seems like it's reading too low. Maybe by 750 to 1000 Rpm's. But I may just be misjudging the RPM's. It may read fine. But why doesn't it register at idle. I realize that his 88 is going to be HEI and therefore be higher voltage on the coil but I figured the tach would still work on mine. Oh, number of piston switch is in the correct spot,8 (I have a 307 btw). I know I hooked it up right or I wouldn't have gotten anything.

ANY ideas?????????

11-14-2007, 10:29 PM	#1
69C10@16 Registered User Join Date: Aug 2007 Location: Greenfield, MO Posts: 215	Aftermarket Tach ? Picked up a tach off a friend. He had it in his 88 Chevy w/a 350 all stock. It worked great. I hook it up to mine, 12V, GND, Neg on Coil, and it doesn't read at all until I rev the engine and then it seems like it's reading too low. Maybe by 750 to 1000 Rpm's. But I may just be misjudging the RPM's. It may read fine. But why doesn't it register at idle. I realize that his 88 is going to be HEI and therefore be higher voltage on the coil but I figured the tach would still work on mine. Oh, number of piston switch is in the correct spot,8 (I have a 307 btw). I know I hooked it up right or I wouldn't have gotten anything. ANY ideas????????? Last edited by 69C10@16; 11-14-2007 at 10:30 PM. Reason: Typo, stupid me. :)



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