What all do you need or have to do to hook up a tack i have been told that is immposible but i know better

 

Heres some tach info, includes some pics.
how do wire in a tach in a 91 - Dodge Cummins Diesel Forum

 

Here is mine that I installed, runs off the crank pulley.

https://www.dieselbombers.com/5-9l-r...uge-mount.html

If yours is a 91.5 there is a slim chance there is a factory plug under teh dash.

 

Bobby, it was not real common till 92 for the plug. I guess its a hit or miss thing on the factory tach plug til 92.

 

My 91.5 had no crank sensor. If it has a VR on the firewall then it has the early I/C PCM without the built in VR which doesn't require the crank sensor to tell the PCM the engine is running, which doesn't, well, you get the picture.... no tach plug.

 

Good to know! I just thought it was teh intercooled trucks! I'll change my post, THANKS!

 

sp how would you wire a tac into the alt?? the link up top wasn't the best for that solution.. what do you need to make it work??? or would it be better to go with the isspro set up??

 

I did the ISSPRO with their crank sensor kit three years ago, no complaints. Maybe a bit more expensive than some other solutions out there, but it's simple, accurate and reliable, no complaints.

 

Me too. Working good for 2 years.

 

i was going to probably put a glow shift tach