Charging system problems

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
Got a series of weird problems.

1. Went drifting with friends, fan exploded and ripped my Mishimoto up.
2. Got another Mishimoto, 2 electric fans and a radiator probe thermostatic control.
3. Went drifting again, and lost my power steering. Going to the gas station my dash lights were dim. Dont remember voltage(voltage is read from Turbo timer).
4. At the gas station, with the key on, there was a weird tapping noise coming from my motor. I tried pulling the EFI fuse, but nothing made the tapping go away.
5. Went home and a friend unplugged an injector and the tapping got slower, unplugged all the injectors and the tapping got progressively slower then to a stop with the last injector unplugged.
6. Reflashed maftpro to another map and the tapping stopped with the key on.
7. Tried to drive it and I could make it like 1 mile before my voltage would progressively drop its way to 7.9V by the time I got home. Car barely runs by any means at 7.9V.
8. Replaced the alternator and battery and now I have a cruising voltage of 11.3V with the lights, fans, stereo, everything necessary for driving at night on.
9. Same voltage at the alternator as I do at the battery. So I still haven't figure out that problem completely.
10. Now when I go to start the car it barely runs and is super rich all the time. Idle AFR=10.0. If I reload another map the car runs great. BUT goes lean under boost like 13.5AFR, no matter how drastic I get with parameters there is little to 0 difference. If I shut the car off then to make it run I have to reload a map or else it will stay at 10.0AFR.
11. I tried updating the Translator to 4.89 to 5.00, still having the same problem
12. I've had a similar problem once before where my car would go lean under boost. I thought it was my methanol not working. But turned out being I just had to reflash my computer and the problem went away.

Seems like my Translator is starting to work intermittently.
 
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dbsupra90

toonar
Apr 1, 2005
2,374
0
0
indiucky
that is still low voltage. pull the big alt fusible link in the fuse box. you will have to pull the bottom off and unbolt it. i had a similar problem and the fusible link was cracked. not all the way blown, so it was working just had a big voltage drop across it.

is your abs light on?>

if you unplug the mpro and start the car, does the voltage come up?
 

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
dbsupra90;1441453 said:
that is still low voltage. pull the big alt fusible link in the fuse box. you will have to pull the bottom off and unbolt it. i had a similar problem and the fusible link was cracked. not all the way blown, so it was working just had a big voltage drop across it.

is your abs light on?>

if you unplug the mpro and start the car, does the voltage come up?

Ill replace the fuseable link.

Nope ABS light would only come on when my voltage dropped excessively low before i replaced the alternator and battery.

I will try unplugging the MAFTPRO before I replace the ALT fusable link.
 

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
Replaced the alt fusable link. Same problem except my voltage now drops below 11.3v, drove home from the parts store down the street at 7.7v.

Tried unplugging maftpro, no voltage difference it runs terrible.

I would take the alternator back off and have it tested but I'm absolutely so frustrated with my car I don't want to look at it.

I'm running a 2jzge na-t 7m electronics. Alternator on it is a 100amp alternator for a 91 Lexus ls400. That's the only alternator kragen had with the correct plug in the back and the right mounting points.
 

dbsupra90

toonar
Apr 1, 2005
2,374
0
0
indiucky
that sucks. sounds like the problem started when you replaced the fans. what fans are they and how do you have them hooked up?

when the voltage is low, have you noticed any of the wiring getting hot?
 

89supra7mgte

New Member
Sep 20, 2009
797
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0
colorado
This is probably the dumbest but simplest questions, is the alt belt tight enough?

Do you have power on the exciter wire on the alt? BTW does the battery light come on on the dash? If its not charging it should be on?

You said the alt is for a dif car is it possible that is supposed to spin the opposite direction? Dont ask me how that would be but i ran into once at work.
 

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
Yup belt is tight.

By exciter wire you mean? The wire that goes to the alt fusable link that charges the battery. Or a wire in the 3 wire clip that plugs into the back?

I'm not really sure. My alternator is for a 91ls400. All the usdm 2j alternators apparently have a long clip not the round one like I have. Anybody know if an alternator will only work correctly if spun the correct direction.
 

89supra7mgte

New Member
Sep 20, 2009
797
0
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colorado
Not sure which wire it is but one of the three in the back of the alt should send juice to it, this in return allows alt to charge battery
 

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
Heres the pinout for my 91 ls400 alternator.

p1446222_1.jpg
 

89supra7mgte

New Member
Sep 20, 2009
797
0
0
colorado
OK that helps. not entirely sure which one it is still, but check all 3. The ignition should have bat voltage koeo. The sense wire might be the one that allows the alt to send power back to battery. and the lamp is well for the lamp switch on the dash, looks like battery. Does that light come on when you turn the key on? look in the tsrm for the correct testing procedures.
 

osama1234

Noob
Jun 30, 2007
87
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38
vancity
This page should help, and the page before, http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=43

I would have also thought it's the alternator, but you've replaced it and the voltage seemed to have come up. So it's tougher to say now.

It might seem to be a stab in the dark (which it is), but you can disconnect the battery and use an ammeter to see how much power the car is pulling from the battery when it's turned off. It should be less than 0.2 amps for sure (i dont know exactly), but if it's more, then there's definitely something weird going on.

If it seems ok there, pull all the fuses one by one, and start the car each time in between, to see if there's one specific one circuit that's perhaps drawing too much current when the car is running. (so if one is drawing too much current, you will have 11 volts, but when you remove that fuse, your voltage will go to a normal 13-14 volts).

Good luck, man electrical stuff can be a pain.