Voltage Drop, what should i do?

[empera]

what can i do to stabilize my voltage. Everytime my electical fan goes on i get a nice voltage drop. I'm also running a few other things such as an amp, lcd screen and some gauges. My optima is pretty much dead and i will be getting a new, regular, battery soon. since this is my 3rd optima killed. I'm also looking to get an mr2 alternator to bump up the amperage. But if you have better suggestions please let me know. I'm looking at "voltage stabilizers" on ebay but i'm not sure if i would trust them.
Any Ideas?

Thanks

 

[tlo86]

capacitor?

 

[CRE]

A capacitor or a "voltage stabilizer" (cough small array of capacitors) isn't going to prevent your voltage from dropping due to a constant load.

If it's due to whatever extra electronics as you've got in there you should do the math and see what size GM alternator you're going to have to make fit. An alternator from an MR2 isn't going to do much better if you're already drawing enough that you're getting everything the alternator's got to give and still depleting the battery. (That's a lot of power, by the way. You doing a lot of short trips or city driving?)

And before anyone asks or suggests it, no, adding another battery won't to crap if the electronics aren't off long enough and the alternator isn't providing enough power to charge TWO batteries.

Either add up the numbers or better yet actually measure your power consumption. Then look for the right solution.

 

[Poodles]

optimas have great warranties, and they don't leak!

swap it out as it should still be under warranty

I'll have to search around, but I remember finding a high output alternator on another website, but it wasn't cheap...

 

[gixxer750]

The problem he's having, is going to show up on his aem logs.

He will have a small voltage drop to around 11.0 volts or so when the fans kick on or when he turns his headlights on. It will last for around 1.5 seconds, and make the aem freak out. The car will usually lean out for a second( or run pretty rich) and then go back to normal when the voltage comes back up.

Lots of grounds, clean all existing grounds, check for voltage drops in the factory wiring. Also, you could upgrade your alternator main wire to a little larger gauge. Helped with this problem greatly.

 

[empera]

cool thanks chris, i'll try that out.

 

[3p141592654]

There is a high-amperage MR2 alternator available for the MR2s with electric power steering.

Unfortunately the case is much larger than stock, and interferes with the 7M crankcase vent hose behind it. The terminal positions are also rotated and that requires some rewiring.

 

[CRE]

Some GM alternators fit just as well, are smaller and still come in hifher output models... same amount of rewiring required, but they're usually alot cheaper when compared amp for amp. That's why I mention it, they're extremely popular with the Toyota truck crowd and pnp wire adapters are available premade.

 

[daught]

On SOME alternator, I have no idea if it will work or give improvements on supras, changing the diodes for better ones will increse the output. Maybe someone that did this on a supra can comment on this and give more details.

 

[gixxer750]

Is it a constant voltage drop the entire time the fans are on, or is it what I described?

 

[empera]

its a dip from when the fans go on but it kinda stabilizes but i think theres still a small drop. I will keep my eye on the voltage read out on my rev meter and see how much of a drop there is and will get back to u.

 

[hottscennessey]

Do you have a battery relocation?

If so did you run a ground to the block?

 

[IJ.]

^ that and does the ECU have it's own dedicated power path from the battery through a relay?

 

[figgie]

Electrical wiring

that is what is for lunch!

first thing I would address.

Grounds grounds grounds.

To the block. the the front, and one more to the rear. Voltage drop means that you are exceeding what the alternator can put out. Which would make sense. The feed back wire is located on the guage cluster if I recall correctly. This is great for lights and what not but not so good for adding more electrical accessories.

 

[empera]

lol biggest headache ever...electrical wiring.

Battery is relocated, grounded to chassis. Block is grounded to chasses, just as it is stock.
ECU is the AEM EMS so the wiring is pretty much all through the stock wiring harness...

 

[figgie]

lol biggest headache ever...electrical wiring.

Battery is relocated, grounded to chassis. Block is grounded to chasses, just as it is stock.
ECU is the AEM EMS so the wiring is pretty much all through the stock wiring harness...

psst

that is your problem

The chassis is at a very minimum 16 year old and on the other side, 21 year old. That much time, corrosion between the spot welds would happen. Deterioration of the electrical path is a given.

If you still have electrical problems after that much grounding, then your alternator is being overworked.

So basically. you need to ground the battery to chassis AND in addition, ground to the engine block and then send a ground to the FRONT of the car too.

 

[empera]

ah, figures...so run some ground wire from battery to block also.

i hope i have thick enough cable.

 

[gixxer750]

Battery Needs to be grounded to a CLEAN spot on the block with 4 gauge or better.

 

[Justin]

Werd, Everyone has hit the nail on the head: Grounds.

I have a stock 80 alt and I run 800watts RMS to my stereo, and tons of other electronics. I have also replaced damn near anything that could be considered a ground in my engine bay. I never have lights dimming, or voltage drops.


Good luck man, electrical stuff can be a frickin nightmare!

 

[figgie]

May I suggest running tefzel wiring at the very least and spec55 if you can flip the coin.