Running Rough - Power Charge System, Weird Tach Output (Page 1/1)
fieromatty AUG 16, 01:55 AM
Hello Everyone,

It has been a while since my last post. My fiero doesn't get much love since I picked up my new Wrangler.

Lately, it has been having a really rough time. It all started with my alternator bearings going out. I replaced the alternator, and the battery because It was about that time (plus my buddy works at interstate and gave me a great deal). Its like I have a parasidic draw on the battery. It will eventually drain after a few days of driving. My buddy tested the battery and assured me its good. My tach is going crazy, it hops around reading the actual tach speed at kind of a logarithmic way (fine at idle, but goes up to 6000 at about 3000 rpm). I don't know what is going on.

Maybe its the ICM.

Its a 2.8, all grounds are new and battery cable and ground cable are new as well.

I am at a loss.
Gall757 AUG 16, 09:07 AM
There could be more than one problem. Do you know how to test for a draw on the battery? I would do that first.
shemdogg AUG 17, 01:38 AM
Is the alternator working? whats the volt meter say when the motors running? Should be above 13.5 at idle
Crazy tach could be bad filter ground/or power wire

shem
fierosound AUG 17, 10:40 AM

quote
Originally posted by fieromatty:

It all started with my alternator bearings going out. I replaced the alternator, and the battery because It was about that time
Its like I have a parasidic draw on the battery. It will eventually drain after a few days of driving.




A bad diode/short in the alternator can do that...
Recheck all the wiring you installed for a short too.


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[This message has been edited by fierosound (edited 08-17-2017).]

altownsend JAN 21, 07:28 PM
I think that I have this problem:

Symptoms:

With key in the 'On' position, the volt meter reads 12 volts
With the engine running, the volt meter is almost 'O", when I turn on the parking lights, the volt gauge goes to zero.
Testing the battery with a volt meter, with the engine running, the voltage was 11.5 and 11.59 volts respectively.
I cleaned the terminals at the alternator and the contact block with the wire that goes to the battery.
With the engine running, and when I turn on the lights, the volt meter bottoms out to the left (at : O), the temperature gauge will also flicker to the left.
The engine is also running rough, and it has stalled out several times.
olejoedad JAN 21, 08:15 PM
With the key in the ON position, does the BATTERY CHARGE light come on?
Does the light glow with the engine running?
Crasian JAN 21, 10:01 PM
It sounds like the “new” alternator isn’t working.. should be above 13 volts with the engine running

-Crasian