tachometer slow response

[dizdak]

last couple times i have started the truck i have noticed that the tach seems to not respond or only show around 100rpms, then usually after running for a few and them a little slap of the throttle it picks up and sits where it should... where should i start with seeing if there is just a bad connection or what not? or should i even worry since so far it picks up and seems to be working correctly after the engine sees some rpms to make the needle move a time or 2?

 

[mjs2011]

I have been having some issues with the tach in my truck as well. It bounces around at times. Where does the tach get its reading anyway? I know some diesels have a sensor that counts the times that the front pully turns around, not sure with these IDIs though.

 

[dizdak]

from another post i had it appear the tach has 2 wires that run out toward the IP... look up my other post, its about tach issue as well..