74' tach
Thread Starter
Cruising
Joined: Mar 2006
Posts: 10
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From: baconton ga
74' tach
Can anyone help me troubleshoot the tach on a 74? the car is stock. any literature available?
thanks,
Larry
ldcoop1@aol.com
thanks,
Larry
ldcoop1@aol.com
Le Mans Master
Joined: Mar 2000
Posts: 9,127
Likes: 2,326
From: Pottsville, PA. USA Home Of America's Oldest Brewery Yuengling
Unscrew the cable from the distributor and turn the end of the cable. Have someone watch the tach to see if the needle is moving, if it is then the tach is ok.
If it isn't moving then the cable is either bad, unhooked from the back of the tach, or the tach is bad. To check this push the clip in on the back of the tach, while holding it in pull the cable out. Once the cable is out spin the back back of the tach if the needle is moving then you have a bad cable.
If the cable and the tach are ok then you have a bad tach drive gears in the distributor. The tach drive gear is inside of the bronze fitting where the cable hooks up to. Most times when this gear is bad so is the center shaft gear. Both will have to be replaced. You will need to remove the distributor from the engine.
If it isn't moving then the cable is either bad, unhooked from the back of the tach, or the tach is bad. To check this push the clip in on the back of the tach, while holding it in pull the cable out. Once the cable is out spin the back back of the tach if the needle is moving then you have a bad cable.
If the cable and the tach are ok then you have a bad tach drive gears in the distributor. The tach drive gear is inside of the bronze fitting where the cable hooks up to. Most times when this gear is bad so is the center shaft gear. Both will have to be replaced. You will need to remove the distributor from the engine.
