ricknbird350

iTrader: (21)

i just wired up a autometer tach in my 98 t/a and it has 4 wires, black,white,green,red.

red i ran to key on power, black to a good ground
white to the dimmer switch for light, and green i ran to the engine speed sens. wire that comes out of i think number 35? its white. and i dont get any signal. well i was drivin home one day and it decided to work. then it just quit workin again. so i tested and double checked every wire and there is no conection problem anywhere..

so where do i look. is there a different place i can pick up a signal that doesnt involve tearing the car apart?

Doubledip

may require a pull up resistor setup... signal out of ecu is most probably too weak for the tacho to read..

place a 3K resistor across the red and green wires of the tacho and see if it works... ( i guess the tacho possibly worked when you were reving it pretty hard)

ricknbird350

iTrader: (21)

o. actually it was idling. then it just quit as if i cut the signal wire. putting a resistor in that wont hurt the pcm?

Doubledip

if your worried about it hurting the pcm then only touch it briefly to see if that is the problem... if it works then you need to by an expensive tacho booster.. have used the resistor trick for many years and never had a problem... the LS1 PCM's have it built in and can be switched on/off via tuning software