moore111

i have a 91.5 and i really really want to get a tach working for it!! does the 91 have a factory plug already?! i do believe i found one under my dash with 4 wires with some purple stripes n stuff not sure. it was a female plug tho. if it isnt the tach how hard is it to do anyways!? thanks alot!

KD93

Check these out from the sticky. I don't know about your year model, but these should help.
https://www.dieseltruckresource.com/...d.php?t=185725
https://www.dieseltruckresource.com/...58&postcount=3
https://www.dieseltruckresource.com/...d.php?t=236340 https://www.dieseltruckresource.com/...d.php?t=173561

Onemoparnut

The 91.5 doesn't have a tach plug from the factory. I have the isspro setup on mine with 2 magnets glued to the balancer it works great.

thrashingcows

I have the same set-up as Bill....Works great!!

Toughest part was getting the magnets 180* apart...it wasn't until I messed around and finally got them mounted that I realized I could have pulled the balancer and done this on the work bench....would have made things a lot easier.....