newer battery and nissan alternator since the FI conversion on my EA82..I have recently noticed that when the signal blicker is on, the constant humming of the fuel pump becomes wavy (sound of pump increases and decreases) plus the rpm drops slightly and the car gets a little more shakey...

My car has done this for the three years I've owned it.

Is your idle too low? Do you have sufficient voltage from the alt at idle?

Your volt gauge probably bounces a little too.

My car has done this for the three years I've owned it.

Is your idle too low? Do you have sufficient voltage from the alt at idle?

Your volt gauge probably bounces a little too.

..the rpm set at 850-900..voltage at 14.5+..

found the problem...alternator putting out 14.6V and the fuel pump getting only 12.67V. without any other load on...bad connection along the wire somewhere..

found the problem...alternator putting out 14.6V and the fuel pump getting only 12.67V. without any other load on...bad connection along the wire somewhere..

 

Interesting. I should test mine. I've had some corroded wires in my car causing high resistance.

Interesting. I should test mine. I've had some corroded wires in my car causing high resistance.

..once any load is placed on the system the fuel pump was only getting 12.2 v....2.5v less then the alternator..a large difference..I did find a weak connection,...repaired it ...so now the voltage is at about 13.3v..certainly better but the problem still remains the same ... so when I have the head lights, blicker light plus stop light on all at once... the pump will slow down and for a moment I can hear a high pitched noise...runs real smooth as long as no extra load is placed on the system...

Battery was the problem..fairly new battery and although the weather has been warm the voltage was at 100%+ until last night when temps fell near freezing..the battery was near dead and will not hold the charge..