I was going through some 120 mph clusters to sell and got the 6 cyl and 4 cyl mixed up at some point..

Is there any way (besides hooking them up in my car) to tell them apart?
I know the tachs are the only diffs between them ,so is there like a number on them or something?

thanks for any info you guys might have...

If there is a value marked on the Tach capacitor, a 4 cylinder should have 0.01 (uF), and a 6 cylinder should have a 0.0082 (uF).
At least that is my understanding. I am trying to determine the same thing with some of my spare gauges.

The link below may be of some help on this topic.


https://www.fiero.nl/forum/Forum2/HTML/125683.html

[This message has been edited by hdryder (edited 06-29-2015).]

All dukes and the 85 V6s were front lit gauges. 86-88 v6s were back lit gauges. All dukes had a redline of 5k showing on the tach....v6 tachs showed a redline of 6k. 120mph gauges were only available with 86-88 v6s, so all 120 mph speedos were backlit. All dukes and the 85 v6s had an 85mph front lit speedo. You could get an 85 mph backlit speedo in an 86 SE (not sure about 87SE).

Another way to look at it....if it had rally gauges, it was backlit...if it didn't, it was front lit. Front lit tachs have a second gauge in them (volts for the 84, oil pressure for 85-88), back lit do not.