Tachometer signal from alternator

[George Da Porge]

In 2104 I had engine pulled to put in new tranny. The tach/hour meter was original (1990). When engine reinstalled it took a bit to get the tach running. Mechanic bypassed signal wire between the tach and engine and tach worked. He put new end on wire at alternator and we were good to go. However, hour meter operation wasn't consistent so later that summer I replaced tach/hour meter combo. Tach worked for a couple weeks then notta! Hour meter no prob (I know they're different signals (just FYI)). Was going to run new wire between alternator and tach last year but didn't get to it. So I'm questioning if the wire is the problem? Also FYI - I've been running the engine slower to avoid too high rpms. Ideas?

By the way, I found an engine belt with hinges so I can move the alternator to the side of the engine, so it won't take an hour to get the oil filter off! It'll be sweet!

Ok, that last part's a joke, just in case you're wondering.

 

[centerline]

first, disconnect the tach wire from the alternator and test the post for power.... with the engine running, it should be putting outAC power at 6.5 to 7volts... NOT DC..... if you are not getting power, replace the alternator, but if you are getting the 7vAC, then move on to the next step.
disconnect the current tach wire from both ends, and then run a temporary jumper wire from the "tach" post on the alternator, directly to the tach (it does NOT have to be routed thru the loom, but by the most convenient and quickest route, because its only going to be used for a minute)....
then start the engine and see what happens....... if it works, replace the wire thru the loom... if it still does not work, replace the tach head....

 

[George Da Porge]

Great step by step centerline! Thanks!