Crazy Tach

[D'Mann]

The Tach in my '06 250 is having intermittent problems. Some times it seems to function properly, but some times it just goes crazy. I first noticed it about two weeks ago. I was driving on the interstate and looked at the tach and it read 1100 RPM, I was doing 75 MPH. I thought that was kind of funny, so I started looking at it a little more often while driving normally. Over the next week it would sometimes look correct, sometimes read a little low, and sometimes drop to below 0. Now during all of this the engine seems to be driving just like it always has, awesome, and mileage has not changed a bit.

Today I double checked every fuse that has to do with the instrument cluster, and they were all good. After checking the cluster the tach did something even stranger, it started reading about 1000 OVER what I would expect, still no change in how it drives.

Modifications:

Intake
edge Juice, no attitude


Anyone ever see this?

[D'Mann]

OK - update

check engine light came on after changing fuel filters three weeks ago. didn't come on until I took a four hour drive from Raleigh to West Virginia to do some 4-wheeling. when we got there it was 4 degrees out. next morning I crank it up (after waiting for four glow plug cycles to make sure it was warm) Check engine light stays on.

I fly out of town for a week, and come back, light still stays on. So I reset the computer. After reset, so far (knock on wood), the tach has worked fine, and the check engine light is out. I fully expect the tach to be messed up again when I get back to town friday, but for now all looks good.

B

[Clay Henry]

Glad you got er fixed...maybe... and "welcome1" to Powerstroke.org!!

[~CrazyDiesel~]

Welcome!

I am not too far away from you, just north of Raleigh.

[D'Mann]

yeah, I've been to Butner a few times back in the day.

Nice to see people from my neck of the woods.

[D'Mann]

OK, the tach is still crazy. But I have narrowed it down to the cluster. I finally got the attitude in for mu Juice module, and it has the tach on there. The sending unit is apparently sending the correct units, as the attitude shows the correct RPM. But the dial tach in the cluster is still going psycho. I'm not going to worry about it right now, but it might be a bad ground on the cluster, or a bad tach. I'll probably get a tach out of a wrecked '06 in a couple years.

B