tachometer not working right

[olskool]

on my 1986 monte carlo ss the tachometer is way off, running up faster than the engine. i put on a tried tachometer filter from dixie restorations. that did nothing. does anybody have an idea? help will be appreciated, i am a professional transmission man, if you have a question just ask.

thanks mike

 

[57 Handyman]

Olskool, several years ago, I added a resistor to the tach circuit board which restored functionality to my device. I can't recall the value of the resistor, where to install it, etc. If you do a search of this site on repairing stock tachometer, that information should pop up. Just so you know, the cost of the resistor was less than $1. Good luck!

 

[olskool]

i have a unified crossfire cap on the accel distributor, would this cause this sort of problem?

 

[pagrunt]

i have a unified crossfire cap on the accel distributor, would this cause this sort of problem?

Not saying it is but if possible try a standard ordered cap to ensure it's not part of the problem.

 

[hangar401]

on my 1986 monte carlo ss the tachometer is way off, running up faster than the engine. i put on a tried tachometer filter from dixie restorations. that did nothing. does anybody have an idea? help will be appreciated, i am a professional transmission man, if you have a question just ask.

thanks mike

Tach on my 79 Calais does the same I was told there is a switch on the tach for 4 6 and 8 cylinder settings mine has been that from when i bought it Dec.78 but have yet to pull the cluster to find out for sure maybe this spring

 

[83MonteCarloSS]

How far off is your tach? Mine is off in my 83 SS but cannot remember how far. I think 200 - 300 rpm. I didn’t find out until my new distributor went in. The new distributor links to my phone via Bluetooth and has a tach in the app. I haven’t looked into fixing it yet.

 

[PBGBodyFan]

The 86-88 tachs are more prone to the high reading issue, in my experience this repair fixes 90-95% of them: http://www.montecarloss.com/community/ubbthreads.php?ubb=showflat&Number=646206

 

[86 Salon]

My 86 Cutlass tachometer was erratic. I soldered the tach shorting adapter to the circuit board per Olds bulletin # 86-6-135. I did this probably 15 years ago and the tach still works fine,