Aq271 Tacho issues

[Sam Jenkins]

Hi ive just changed all the gauges on my dash to kus Analogue gauges.
Im having issues with getting the rev counter to read properly even after adjustment. ive taken the signal for the tacho away from the coil as this made the gauge very slow to respond if at all.
Its now on the w post on the alternator but is reading inaccurately with no more adjustment. Has anyone else had a problem like this and if so what was your solution
Cheers Sam

 

[Scott Danforth]

The alternator will be woefully inaccurate. First the Valero alternator is not that good. Second, the brackets don't keep the belt tensioned enough

Reading off the coil is the best way. You could have a bad tach (new doesn't equal good)

Did you disconnect the rev limeter? Its a little black box mounted to the transom connected to both sides of the coil. They fail and can cause issues

 

[Sam Jenkins]

i can only get the rev counter to work smoothly off of the alternator but is reading inaccurately.
I took the speed limiter off some time ago with no issues. As soon as i connect the tacho up to the - side of the coil it either doesn't work or it jumps and doesn't follow the engine speed. Could a newer rev counter be too advance for the ignition coil of a 5.7
Cheers

 

[Scott Danforth]

Could a newer rev counter be too advance for the ignition coil of a 5.7
Cheers

No, however is the tach set to 8 cylinders?

 

[Sam Jenkins]

Ive adjusted the setting on the back which alters the reading but seems to move it in the wrong direction. Im starting to think the tacho might be at fault

 

[Scott Danforth]

Im starting to think the tacho might be at fault

line 2 in post #2 called that out

 

[ESGWheel]

I tried to look up your new tach gauge and only came up with one that also had a digital hour meter read out. Does yours have that feature? I ask because the typical switch setting of 4, 6 or 8 cylinders is not there. Instead, it’s a pushbutton with a seemingly complex set of instructions to sequence thru the menu to get to the correct setting and perhaps the issue lies there. How is your tach set to 8 cylinders?