Inconsistent tachometer

[keegan89]

This has always been a problem it has just happened a lot more often recently. 90% of the time my tachometer is reading about 1000 or more rpm’s high. very rarely is it correct. does anyone know how i can fix this? thank you

Truck is 1989 Ranger with 4.0 ohv swap 5 speed

 

[franklin2]

What are you using as a reference to what the rpm really is?

 

[keegan89]

What are you using as a reference to what the rpm really is?

my ears, i know im not idling 2100 rpms

 

[Broosedamoose]

What was in it before the swap?

 

[keegan89]

What was in it before the swap?

2.9

 

[gaz]

@keegan89
My timing light also displays engine RPM; if it didn't and I suspected that my tachometer was not reading correct, I would verify my suspension with a known good tach.

You could go to an AutoZone and let them take a look with their timing light, comparing the readout to your cluster tach...will they are at it.

 

[keegan89]

i actually had my smog done recently and was able to see the rpm reading at idle and it did not match up, not sure why my tach would just randomly start acting up

 

[franklin2]

i actually had my smog done recently and was able to see the rpm reading at idle and it did not match up, not sure why my tach would just randomly start acting up

Because it's about 30 years old? The one on my 86 ranger didn't work. Until I looked a little closer and found the needle had broken off, the tach still worked. So I superglued a wire tie I cut off onto the center hub and that worked for years. Was It accurate? Not sure, I guessed where to glue it.

Your needle may have slipped, the spring that returns it to zero may be sprung, could be anything.

 

[keegan89]

not 30 years old, but thanks for the help