tach again

workinonit · 07-20-2007, 03:21 PM

I dont know if any of you have read my other post or not but heres a little refresher. I have a 77 stang II with a mid 80's 351W the problem i am having is the tach. acording to the vin the car cam stock with a 302. When I bought the car it already had the motor in it. but whoever did the wiring had something to be desired. so after going through the cars wiring nightmare. i found that the tach is reading like a 4/6 cy . meaning its way off. at idle Im at about 800-1000 rpm. but the tach is reading about 15-1800 . I tried to insatll an aftermarket tach and it would go dead about 8 hundred.. 2 questions. has anyone else had this problem. and is there another signal wire that I can hook the aftermaket tach too.
thanks in advance.
Bill ( Waterford, Mi. )

[IMG]local://upfiles/69264/B1972CAC66C0465B8F54E4521413E32A.jpg[/IMG]

[IMG]local://upfiles/69264/2AB7F28F559C439AB027F609FF1FBC68.jpg[/IMG]

my77stang · 07-20-2007, 04:04 PM

should be hooked up to the coil, unless you have a aftermarket ignition box and then it should be hooked to it. the reading high on the factory tach sounds like it doesnt have a V8 tach adapter on the back of the cluster. have you pulled the gauges and checked to see if teh box is on the back of it or not? if your trying to use your aftermarket tach, is it the only tach you are hooking up? lastly, i saw my aftermarket tach going dead and coming back to life on me once, i ended up replacing the alternator (lifetime warranty and their machine was down so i do not know if it was bad or not), but my voltage regulator WAS bad and needed replacing. they are like 15 bucks and are prone to failure. also there are a couple different regulators, make sure the replacement has the same letters in the same locations on the plug.

i hope this helps, cause its alls i gots [8D]

workinonit · 08-06-2007, 11:28 AM

well I fixed it . it was a bad coil. Ive never had a coil give a false tack reading like that before. I replaced it with an accel supercoil and everythings good now . thanks for all the info though. might come in handy someday