What The...........

smokinLS

Registered User
tach troubles

ok folks i have a good one for ya. i have a 92 cougar LS with a 3.8 and my tach reads 3500 rpm at idle and stays between 3500 and 4200 during acceleration. does any one know what could be causing this and how i could fix it?
thanx
 
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the engine does run fine, i was hoping that the tach is bad. i took it out and am trying to find one in a salvage yard since ford discontinued it. if it turns out to be electrical can anyone tell me if and where there are any relays to check or where the rpms are read from, ie. distrib. or any other part.
thankx for the input so far
 
smokinLS said:
the engine does run fine, i was hoping that the tach is bad. i took it out and am trying to find one in a salvage yard since ford discontinued it. if it turns out to be electrical can anyone tell me if and where there are any relays to check or where the rpms are read from, ie. distrib. or any other part.
thankx for the input so far
There's no relay or fuse to check if the other gauges work.
The rpm signal from the ignition module (behind the front bumper near the passenger side headlight) is sent to the ignition coil (next to the air filter housing). The ignition module, coil, and rpm signal are O.K. since the car runs fine. From the coil the rpm signal (tan-yellow wire) is fed to the VMM and tach via a 1.8K ohm resistor. The rpm signal wires at the instrument cluster/tach and at the VMM are also tan-yellow.
 
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