Ok, on the 93 T/A I just bought, it has a 95 M6 in it. This is due to the car being originally an auto. So, WITH a MSD Digital 6, the tach was showing the right signal, says the former owner. Without, like it currently is in my possession, the tach gets nothing. Why would this be, and can anyone give me some insight?

 

TTT, come on, someone's got to know something........

 

Try and give us some more insight to what the problem is, I am not understanding.
Your saying it does not have the MSD box anymore and you need to get a tach signal?

 

Yeah, the car does not have the box anymore, and when the box was taken out, the tach lost the correct signal. When the car starts now, the tach will initially come up to about normal idle, but when revved, the tach drops down and bottoms out instead of acting normally. With the digital 6 box, the previous owner said it acted fine. I know there's a tach filter, and that's connected to the coil, but I'm wondering why the stock system wouldn't pick it back up when the box was removed.

If it helps, it's a 93 car, and a 95 M6.

 

well it sounds like its trying to pick it up but not getting good connection. I would check all the wires going to the coil and make sure one is not loose, I am not sure which one exactly is the tach wire, maybe someone will get on here and tell us.
If the tach is reading idle initially then I would think its just a loose connection.
The MSD box was plug and play wasn,t it? No wires were spliced or anything?

 

Yeah, plug and play. I have a service manual, and have already identified the wire, pulled it from the coil, double checked it, and found nothing out of the ordinary.

 

Bad Ground?

 

I don't think so. If it was a bad ground, the tach shouldn't show anything at all. I'm getting a Dig 6 for it anyway, but it bugs me right now that I can't watch the tach, and there's no rev limiter either.