75 Tach Problem

[captras]

The tach on my 75 is stuck at about 1000 RPM, ignition off. When the ignition is turned on, it jumps up to about 2000 RPM and stays there, regardless of actual engine RPM, then drops back to 1000 RPM when ignition is turned back off. I have read about replacing the ICB, but have not been able to determine if these symptons are ICB related. Also, how much work is it to replace the ICB, if that is the problem.

Thanks in advance.

 

[L48]

Mine does the same thing. I have been busy with other higher priority repairs and have not had a chance to figure out what is wrong. I am guessing this is why you can buy rebuild kits for the electronics of the tach.

 

[WARVET]

I haven't done mine yet, but your simptoms sound like it's time to replace it. I remember somewhere I saw that there was also a repair kit, but I think you are better off with a new one.

 

[kiwi vet]

Hey captras

Thought this info that might help.

Mid America Motorworks do a 75 Tach rebuild kit Part# 602779, price $58.99 US www.mamotorworks.com if you want to do it yourself.

Corvette America does a rebuild service, where you send in your tach, they rebuild and send back Part # 41735 $ 189.00 US. www.corvetteamerica.com
If you want someone else to do it.

Hope this helps, Good Luck!

 

[kiwi vet]

See the info on the thread under C3 discussion, it might help.

 

[Bob Chadwick]

Merged the two threads and put them under general discussion.

 

[mike weyman]

my 75 did that, i took the circuit out and soldered wires on the board where they were fried, works fine now.