Why doesn't my tach work with HPX ignition?
 

I'm not sure how to tell for sure if I need the tachometer amplifier for my Electromotive HPX ignition in my '73. Tach doesn't move but I tore the car apart 10 years ago and I think the tach worked then but I don't know for sure. How can I tell what I need for sure?

Thanks, Matt

I don't think the early tachs work with HPX. In my case I used a SC tach, works fine.

The signal is different, check the archives.

Good info, thanks. What is the difference cosmetically?

Matt

off topic but what are you using for cam angle signal??
trigger wheel on the front crank pulley?
any pics of your setup because im switching my 3.2 dmecar to a pressure sending setup and will use the flywheel for crank angle but now need cam angle to fire the plugs.
thanks

Well the SC tachs look a little different. Early tachs have a stainless center, SC tachs don't. Different redline. Early tachs held in place with bracket from behind, later tachs use rubber gasket.

Biggest issue is that you'd have to buy one for $100 or so. There may be some sort of adapter/amplifier you can use with the HPX, and the early tach, I'm not sure.

Not sure what you mean about "cam angle signal?"

Here is a picture of the sensor and trigger wheels on the crank pulley on my engine.

http://forums.pelicanparts.com/uploa...1061674342.jpg

This thread (scroll halfway down this page) has more details about the install in my car.
http://forums.pelicanparts.com/showthread.php?s=&threadid=116491&perpage=20&pagen umber=2

I should add that North Hollywood speedometer can install SC tach internals into an early tach to maintain stock appearance. I think a couple of guys have gone that route. PartsHeaven has used tachs or try ebay if you need one.

for a efi system to run in sequentil fuel injection the ecu needs to know where the cams are and crank are. the crank angle will be using te factory teeth on the flywheel that the dme used and for cam angle i need ecactly what you have.who made that pckup and trigger wheel and how much were they

thanks

Gotcha. See:

Visit http://www.clewett.com/

thanks for the link. now what do you use for the crank angle?
the old sensor the dme used on the flywheel??