I'm having problems with my tach not working well upon start-up when its below around 35 F outside. When its close to 35*, it'll start working after driving it a couple minutes. The colder it gets, though, it takes longer to begin working.

When I bought the truck in the spring, the tach wasn't working at all. I replaced the tach sensor, and it worked great all summer and fall.

I've been having problems with a leaky windshield. Do you guys think moisture could have built up in the dash, and freezing could be an issue? It's probably been three weeks at least since it leaked into the cab, though, I've been careful to cover it. The tach problem persists, however, so it seems like moisture probably isn't the culprit.

 

this is strange in my 93 f350 idi the tach doesnt work when its warm it works good when its cold. any ideas?

 

You probably have crap on your tach sensor. Run some automatic trans fluid in the fuel or Diesel Kleen works perfect to. Might fix it.

It can also be the connecters that's close the sensor under the hood. Sometimes simply disconnecting it, blowing on it with your mouth and re-connecting it can solve your problem.

I don't think moisture would be a problem, it's been raining in my cab for 2 years now, and hasn't affected nothing. Just rusting the pedals lol

 

Not sure what is wrong with it, but diesel kleen or anything else in the fuel won't help the tach.

 

Hmm, I will look at the sensor connector tomorrow. I'll be sure to post if/when I fix it. I appreciate the replies.