Out of ideas... Alt not charging...

[Edvo34]

I hardly ever post because I usually find my answer while searching... But this time really stumped.. Any help is appreciated.
My s13 w/ s13 Sr20 is not charging properly
-no dash lights turn on
-Charging at 9.5 volts.
-Car turns on,idles, and drives fine

With this I'm really stumped, I've
-rebuilt the alternator and tested good twice
-Check all fuses and 75amp alt fuse
-replaced the battery
-replaced the gauge cluster

Things to consider.. I've shortened the engine bay harness and relocated it into the cabin.also the chassis is completely stripped because drift car...

It's been such a headache, I've been comtemplating buying a completely stock engine bay and main harness again to start over...

Any help or advice is greatly appreciated.. Thanks.

[RB25GUY]

I've had the same problem it ended up being a red wire was shorting under my dash on the passenger side although I had RB and I had tucked my relay boxes under my dash. Hope you find the problem

[ZenkiKid]

Have you tested known good alternator in its place to see if the problem is still happening?

[silviaks2nr]

Was it working fine before or did you just do the swap? You're using an SR pulley not a ka one right?

[Agamemnon]

The alt is probably not getting the 12v signal it would normally get from the battery check bulb in the gauge cluster.

[Veltall]

i have a jz and was having a similar problem.i would check to see if it has an exciter wire and if it does, check to see if its getting a signal to it. my alternator wouldn't charge unless it was getting a 12v signal to start charging

[KiLLeR2001]

I would go over the FSM on the charging system. EL section, page 14. If problems started happening after you shortened your wire harness, chances are you didn't wire something correctly.

[Trinidrift3]

I have had a similar issue. The power that connects to the alternator can become fried after a while. Its the wire that held on by a 12mm nut on the back of the alternator. i was getting 11v while running. the end of the wire was fried. i cut it back 2 inches because i had slack so it could still reach after cutting the end. put the eyelet (can't think or proper name right now) back on the new nonfried wire and crimped it. voltage went back to normal. worth a shot to check that wire

[Black240Ct]

does your battery light on the gauge cluster come on and turn off after the car is running... or stay on in the case that your only generating 9.5 volts.

there is a two wire plug in the ALt. the white wire has power and the white/red wire goes directly to the battery light on your dash... this allows the alternators resistor to work and maintain voltage.. if its not hooked up it can cause some weird issues, usually running at too high voltage.

[Blk96t]

^^this. Check it I had weird problems with this connector

[Drift_86]

Do you have a ka alternator turned out for me ka alternators don't work on my sr for some reason...

[Cash]

I used a KA alternator on a red top SR for years without any issues.

[Edvo34]

Update: After initially looking through the obvious culprits.. no luck.. So I started at ground one.. Going through basically both harnesses , to find out that the harness was just shit.. It was beyond repair.. So trashed both and started fresh with a completely stock and untouched harness (both engine bay and main). I installed it no problem, connecting plugs as I should.. But.. New problem is it'll crank and crank hard but won't start.. No Fuel No spark.. Goin to start over with this new harness setup and see how it goes... Any new ideas are appreciated!

[1on1]

This happened to me once when I did my swap. Make sure the second plug from the engine harness is locked in under the passenger side panel.

[Edvo34]

This happened to me once when I did my swap. Make sure the second plug from the engine harness is locked in under the passenger side panel.
Update: Got the car finally started.. I completely missed the connector by the fusebox. newbie mistake smh:facepalm::... thanks dude^^^
.. Anyways im still having the charging issue. Before the harness swap it was charging at 9.5V, now it charges at 12.5V (idle). Still low, the hunt continues for a solution for 13V+
Next is to swap in a (Known ) good alternator to see if it changes.. i doubt it, but im desperate to get my car back on the road..

edit: I wanted to see if the alt charged at all.. so for shits and giggles.. i had the car running and pried the Positive terminal slightly to see if it'll stall. It immediately started to stumble if the connection was messed with.. so thats that..

[Black240Ct]

swap to a quest alternator and have no issues or issues replacing an alternator.

[Edvo34]

This happened to me once when I did my swap. Make sure the second plug from the engine harness is locked in under the passenger side panel.
Update: Got the car finally started.. I completely missed the connector by the fusebox. newbie mistake smh:facepalm::... thanks dude^^^
.. Anyways im still having the charging issue. Before the harness swap it was charging at 9.5V, now it charges at 12.5V (idle). Still low, the hunt continues for a solution for 13V+
Next is to swap in a (Known ) good alternator to see if it changes.. i doubt it, but im desperate to get my car back on the road..

does your battery light on the gauge cluster come on and turn off after the car is running... or stay on in the case that your only generating 9.5 volts.

there is a two wire plug in the ALt. the white wire has power and the white/red wire goes directly to the battery light on your dash... this allows the alternators resistor to work and maintain voltage.. if its not hooked up it can cause some weird issues, usually running at too high voltage.

I wanted to see if the alt charged at all.. so for shits and giggles.. i had the car running and pried the Positive terminal slightly to see if it'll stall. It immediately started to stumble if the connection was messed with.. so thats that..
-Also on my gauge cluster the battery light doesn't turn on at all..


I appreciate everyone's help with this.. this has been a headache for me..

[Edvo34]

I've had the same problem it ended up being a red wire was shorting under my dash on the passenger side although I had RB and I had tucked my relay boxes under my dash. Hope you find the problem

The alt is probably not getting the 12v signal it would normally get from the battery check bulb in the gauge cluster.

does your battery light on the gauge cluster come on and turn off after the car is running... or stay on in the case that your only generating 9.5 volts.

there is a two wire plug in the ALt. the white wire has power and the white/red wire goes directly to the battery light on your dash... this allows the alternators resistor to work and maintain voltage.. if its not hooked up it can cause some weird issues, usually running at too high voltage.

^^this. Check it I had weird problems with this connector

swap to a quest alternator and have no issues or issues replacing an alternator.

to everyone suggesting the W/R wire on the back of the cluster.. The cluster itself had a layer of gunk between the bulb and the cluster. I've cleaned it and IT TURNS ON, but just very dim compared to the BRAKE light..also the bulb will only turn on with the key in specific location in switch
..the problem persist with the low charge:picardfp:

[Black240Ct]

batt light should only come on in the ON position.. and then turn off once the alternator is spinning... provided your alternator and such are charging at proper volts.

so batt light should turn off once the car is running... its controlled internally by the alternator.... for the alternator to work properly it needs that resistance of the bulb and W/R wire. so does the light go off now?

[Edvo34]

batt light should only come on in the ON position.. and then turn off once the alternator is spinning... provided your alternator and such are charging at proper volts.

so batt light should turn off once the car is running... its controlled internally by the alternator.... for the alternator to work properly it needs that resistance of the bulb and W/R wire. so does the light go off now?

The light will turn on while cranking the engine. itll turn off once it's on.. bulb is infact working..

I've also replaced the alternator with a known good one.. still no dice
Maybe a culmination of the good alternator conjoined with a separate wire jumped from the cluster to the alternator would work?

thanks again!

[1on1]

IIRC, Engine harness isn't connected to the alternator, the lower harness is. I have a feeling you hooked up your lower harness incorrectly or grounding a wire incorrectly. Try checking your wires again with the diagram below:

https://240sxguide.files.wordpress.com/2014/02/sr20detlowerharness.jpg

Edit: If the above doesn't work, then I'm out of options besides double and triple checking. Voltmeter would help you a lot so you can test for connection.

If you want a better layout, here's a installation guide from wiring specialties: https://drive.google.com/file/d/0B9F33_M_GgENWkk2RlFIWFBka0U/view?usp=sharing

[slow_sr20]

Sounds like a grounding issue. Add a ground wire. Check the resistance of the existing one. Double and triple check.

[dwnshft2drft]

Have you check the ground wire connection from alternator to the chassis? Maybe corroded or loose or maybe strip bolts/nuts

Check the alternator wire into the engine bay fuse box as well. And from the engine bay fuse box onto battery wire.