L28ET aftermarket tach help!!!

[RAG&BONE]

I am having a heck of a time tryn to hook up a aftermarket tach to my 1982 280zx turbo, it tried tying into the tach signal going to the stock tach and tried going straight to the negative signal on the coil both ways give me a eratic signal that obviously is not working. Is there something iam missing???

[nismo dr]

does the tach have a switch for 4,6,8 cyl?

[metalmonkey47]

I am having a heck of a time tryn to hook up a aftermarket tach to my 1982 280zx turbo, it tried tying into the tach signal going to the stock tach and tried going straight to the negative signal on the coil both ways give me a eratic signal that obviously is not working. Is there something iam missing???

 

The trouble is, the aftermarket tach uses a square wave signal, which old ignition systems don't produce. The stock tach doesn't use a square wave signal, which is why it works fine.

 

 

You have a few option. You can either buy an aftermarket ignition box that produces a square wave, which will be $100-200 depending on model (which gives you more benefits then stock ignition control unit) or you can get an MSD P/N 8918 GMR pickup for between $40-50 depending on where you buy it.

 

 

 

 

I learned this after speaking to a ProSport tech because of the same issue on my '81 210. I spent $130 on an MSD StreetFire box and it was more then worth it.

Edited July 11, 2011 by metalmonkey47

[RAG&BONE]

man is that lame! Square wave patter, jeeze i thought i just needed a resistor inline or some thing, so is there anyaftermarket gauge that will work ? or is this the case with all aftermarket tachs? also no my tach does not have a 4,6,8 option. it a PIVOT tach