Voltage Drop When Accelerating?
 

OK i think i have an alternator problem. I'm only seeing 13.5 volts with the car running (lights off). With the lights on it sits around 13.4 volts (unsure why so little drop). But then if i turn my fan on it drops to 13 volts.

But one thing i mainly would like to know is should the voltage to the ecu drop when accelerating? I'm seeing the volts drop to mid 12s. How could the injectors be draining that much?

weak alt?
belt slipping?
weak wiring?

13.5 is a little low, i get i think 14flat running with an s4 alt, with the lights on it drops quickly to mid 13's, under power though it never drops below 13 unless i have highbeams on and my 300watt power inverter, again this is on an s4 alt

Get a cosmo 13B alternator or FD alternator or Even better yet a Cosmo 20B alternator. Stick that on.


Put a An extra 150AMP 4Guage power cable from alternator to battery(or starter Motor).
Put an extra earth strap from the chassis to the engine, and one extra from battery to chassis. Also put a new alternator belt.

The reason the voltage is dropping when your accelerating is your coil packs are drawing mega electricity and the alternator isnt keeping up.

Thanks for the replys. I think i've fixed the problem. It was simply a loose ignition lead. The poor connection must have been drawing extra current through the coil pack and also causing a miss fire i was getting.

It's now running at 14volts, 13.5-13.6 with lights on and doesn't seem to drop below 13.5 when accelerating like before. I might put in some extra power & earth cables just to be safe.

Oh btw this is on a 4cyl piston. I just use this forum because its the only wolf one.