240sx electrical issues

[haze107]

most of the time when i turn the car on, none of the electrical in the car works except for the radiator fan. then i rev the car to 4k or 5k rpm and everthing turns on, seatbelts, wipers, headlights etc. i just need some ideas as to what the problem could be. the cars a 91 hatch but has a 96 twin cam in it.

[blkvrtswp]

Check for a bad alternator or a short in the wiring around the alternator or fusebox.

Alternators should not have to be revved up to produce rated voltage. I recently upgraded to a Quest alternator and I had a similar problem with the old one where it would show 11.xx volts at startup and idle, but when I revved it up it would then show 14.5 volts.

The new/rebuilt alternator eliminated that, now on startup with no rev up I see 14+ volts immediately.

[solallein]

Or really bad ground wiring, if resistance is greater then like 2 ohms from the block to the negative post your grounding isn't good.