GLHS

I seem to have a problem with my N/A.

I have a electric radiator fan, and if I have the radio on and the fan, the voltmeter dips down to 12 when I step on the brakes. The engine also wants to stall out.


What is causing this? Bad grounds, or not enough of them?

I just had the alternator rebuilt.


Thank you.

darkwaveboi

hows the battery? Need replacement?

hugues

Make sure you battery posts are tight. Check your ground (battery - to block).

How old is the battery. If it has been completely drained a few times and recharged in the past, I would get a new battery since it may have shorted and it is making the alt working extra hard all the time.

What happens when you rev the engine, is the voltage going up ? It should go up to around 13.5-14 (u need 13.6 to charge a battery)
If it does not, alternator is no good.

I would definitely upgrade to a better alt like a s5 one (very easy mod) or an fd one (a little bit more work). The e-fan is probably draining too much current, at least more than what the "weak" s4 alt can handle.

Hugues -

GLHS

The battery is brand new, and has never been charged or drained.



The voltage picks back up instantly, if you rev the engine, just a little. The voltage never drops when driving around.


I saw something on here about adding more grounds and running on right from the alternator. Do you think this would help any?

Do you think that the battery being way in the back could affect my voltage problem?

hugues

ok,
so your charging system seems to be ok. 12V at idle with accessories on is a little bit low (you are draining the battery at that point) but if it picks up when you rev, not too bad.

I don't think putting battery in back is a problem unless your wiring in not up to snuff. Check the resistance of your wires (the 2 that go to the battery) to make sure.

You can try to put heavy guage wire from positive terminal post of alt (the nut that is on that black plastic thingy at the top) to battery positive. That may help the alt.

What's the resistance between negative battery terminal and engine block (disconnect battery first, please). If more than .5 ohms,
you can add heavy guage wire from negative battery to engine block.

Good luck in your electrical journey,
Hugues -

banzaitoyota

How many amps {FLA} is the Efan rated at?
Stock stereo or aftermarket with a couple of power hungry amps?

The sock Alt was at the limits of its capacity in 86-88 hence the upgrade in 89 and again in 93 on the FD. Sounds like time for a S5 alt upgrade if all your grounds are good, and your idle speed is correct.

GLHS

Thanks for all the input.


As for stereo, thats funny. I have Kenwood CD player, and one stock 4 inch speaker on drivers side. " Hey I got to have SOME tunes, while at the track".


I guess I will check the resistance and see what that gets.


I always thought there was like 3 grounds in a S4.

I know I have 2 of them, but not a third one.

I have the Starter ground, and the ground from the trans to the firewall, but thats it, shouldn't there be one more somewhere?

I also do not have any of those grounds for the exhaust connected. What are those ones for anyway?

Also I have my E fan ground run separate 10G wire to the battery. I have a heavy duty manual switch with a 30 amp fuse in line, connected to the power line 10G from the battery. I think the fan only draws 10 to 12 amps.