Problem with the tachometer (Page 1/1)
Belgium Fiero FR JUL 27, 06:21 AM
Hello Guys , I have a Fiero 86'

I write this today because i have some promblem with my tachometer.
When i accelerate ( Whether it is at a standstill or with a speed) the tachometer go too much higher.
When we do nothing with the car the tachometer show 2000 RPM and when i accelerate a little bit it go to 4000-5000 RPM directly.
The engine noise does not show that the car is going that high in RPM, I have the impression that the tachometer is showing a false value and much higher than the real one.

Anyone know where the problem could be coming from?

Thanks
Andy
Mike in Sydney JUL 27, 08:46 AM
Sounds like a faulty tach filter. Unplug the filter and jumper the socket where the plug was. If the problem goes away, the filter is probably faulty. If the problem is still evident, look at the ignition control module. The Fiero Store or Rodney Dickman has replacements if needed.

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Mike in Sydney

[This message has been edited by Mike in Sydney (edited 07-27-2020).]

Gall757 JUL 27, 09:02 AM
http://www.fiero.nl/forum/Forum1/HTML/098173.html
J Gunsett JUL 27, 09:16 AM
If the tach filter does not fix the problem, I think your problem is in the R/C circuit in the tach. Here is a good site for this problem.

http://www.fieros.de/en/articles/tach.html

It really helps if you have a frequency generator to set the variable resistor. Hope this helps.

Jack