Jump to content

Tachometer calibration


Recommended Posts

 

My tach reads less than 500/nothing. I can't figure out how to adjust the rpms so the read right (they don't have to be perfect just close ) Just replaced dummy lights and sensors

 

Sent from my moto e5 play using Tapatalk

 

 

 

 

Link to comment
Share on other sites

It's lower than it should be, but considering a Renix 4.0 in need of maintenance can have a pretty shifty idle I can believe it. Don't adjust it before you know for damn sure it's incorrect. Do you have a scan tool for your truck? Can you post a video of what your engine sounds like idling?

Link to comment
Share on other sites

52 minutes ago, Minuit said:

It's lower than it should be, but considering a Renix 4.0 in need of maintenance can have a pretty shifty idle I can believe it. Don't adjust it before you know for damn sure it's incorrect.

Please re-read this comment.

 

Then read it again.

 

And again.

 

Then ask yourself if you really need to adjust the tach. . . 

 

I would recommend that you start checking grounds, sensor values, connectors for green crusties, gunk in connectors, etc etc. Go through all the main cruiser54.com tips. Your tach is most likely reading correctly and needs no adjustment. Run through all the other likely sources first at least.

Link to comment
Share on other sites

I did all the ground cleanings from cruisers tips already and even did the c101 elimination. I was honestly just concerned (from the other manual vehicles I've owned) that the RPMs were too low. If you saw the pictures and think that is where it should be then I'll just leave it alone and enjoy my new cluster it idles just fine i just thought the cluster I purchased was from a 2.5 (mine is a 4.0) and needed to be adjusted

 

Sent from my moto e5 play using Tapatalk

 

 

 

 

Link to comment
Share on other sites

It seems REALLY low to me. At idle when warm it sits at about 250/300 RPMs. And when I step on the gas the RPMs don't go nearly as high as it sounds. At 3500 it sounds like I'm redlining the hell out of it

 

Sent from my moto e5 play using Tapatalk

 

 

 

 

 

 

Link to comment
Share on other sites

1 hour ago, Aidan said:

Maybe I'm crazy lol does this look right for warm idle?23f3546d9663d8e344e98f8bf6a88a15.jpg

 

It seems to be sitting below 500 the warmer it gets

 

Sent from my moto e5 play using Tapatalk

 

 

 

 

 

You're reading it wrong. That's indicating approximately 700 RPM.

 

Note that the tach scale is linear -- all the way around, the divisions are the same size. BUT ... at the bottom end of the scale, they left off the tick for 250. No need for it, because the engine never runs at 250 RPM.

Link to comment
Share on other sites

  • 1 month later...

Reviving this thread for a question that also deals with calibration. I have an '86 2.5L and I bought the truck with a busted tachometer, where idle would read 4,500-5,500 RPMs, and when you're cruising down the highway, the need is pointing direction at 6 o'clock. I like the red clusters anyways, so I snagged a full cluster to swap in and be done with it. Well, the tachometer is playing silly again, and now I'm reading 0 RPMs, even though it is calibrated to 4 cyl. And I'm very sure it is calibrated to the 4 cyl because if the adjuster is rotated the other way entirely, idle reads below the 0 RPM mark, even though it responds quickly anytime I open the throttle; the other tachometer also responded appropriately when throttle opened up. So my question is whether or not I'm extremely unlucky and both tachometers are just botched? I tested for voltage at the ICM and the dash harness, and got battery voltage both times, as well as 0 ohms as well. Any thoughts?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...