New Alternator Recommendations?

23231 Views 18 Replies 11 Participants Last post by norm356, Apr 27, 2017

osscie3

Discussion Starter · Apr 26, 2017

Hi guys,

My battery light turned on today. Luckily the symptoms stop there but I'm planning for the worst as I do my research. My voltmeter looks fine and normal at this point and nothing is out of the ordinary so I'm hoping I don't have to replace the alternator although I'm about due (124k miles). I'm going to get my battery tested first and all that jazz that comes along with it.

If in fact I do have to replace my alternator is there any recommendation that you guys can provide? I don't do any offroading so I don't really need any upgrade. I've just seen some go for $150, others in the $350, and some up in the $450 range. I'd like to save some money but I don't want to buy the $150 one then have the same problem 6 months from now. Any opinions or suggestions are welcome.

Thanks!

1 - 19 of 19 Posts

sealevel

· #2 · Apr 26, 2017

osscie3 said:
Hi guys,

My battery light turned on today. Luckily the symptoms stop there but I'm planning for the worst as I do my research. My voltmeter looks fine and normal at this point and nothing is out of the ordinary so I'm hoping I don't have to replace the alternator although I'm about due (124k miles). I'm going to get my battery tested first and all that jazz that comes along with it.

If in fact I do have to replace my alternator is there any recommendation that you guys can provide? I don't do any offroading so I don't really need any upgrade. I've just seen some go for $150, others in the $350, and some up in the $450 range. I'd like to save some money but I don't want to buy the $150 one then have the same problem 6 months from now. Any opinions or suggestions are welcome.

Thanks!

Toyota FJ Cruiser High 200 Amp Alternator 4.0L 2007 - 2010 2008 2009 High Amp | eBay

SilvFx

· #3 · Apr 26, 2017 (Edited)

You dont say what year FJ you have, but based on miles, I am guessing '07-09.

Rockauto offers remanufactured Denso alternators (2100612) for $117 after return of the core + shipping. My understanding is that these are remanufactured by Denso themselves. Denso is the OEM supplier to Toyota for the alternators.

Core return is pretty easy. I got a reman Denso from RockAuto when I replaced the starter in daughter's 3rd Gen 4Runner

If you have the '10-14, they offer a Denso reman alternator for $138 after core return + shipping.

Google for extra 5% discount code. No affiliation with RockAuto but have been pleased with the price, quality, delivery etc for anything that I have purchased.

thesilkiest

· #4 · Apr 26, 2017

in a pinch you can drive to Oreilly's as well. Get a new belt too even if your old one looks ok. It's a night mare ****ing around with a used one. Much harder to jimmy it on there as it wants to twist like a slinky.

Get a multimeter to check the alternator. Really the best way to find out. Also I went with stock OEM and its been working great over the winter with no issues at all.

https://www.google.ca/search?q=how+...rome..69i57.7201j0j7&sourceid=chrome&ie=UTF-8

ZoSoIV

· #5 · Apr 27, 2017

yup go with the Denso , new is always better but more money ..the reman from Rock Auto sounds good

football751

· #6 · Apr 27, 2017

sealevel said:
Toyota FJ Cruiser High 200 Amp Alternator 4.0L 2007 - 2010 2008 2009 High Amp | eBay

Have you or anyone else used this alternator? That's an awesome price for a 200 amp alternator. That same seller also has a 250 amp for only $20 more! I think I'll send them a message and see if they can provide more specs like an amps vs. engine speed chart.

BacktoFutureToyota

· #7 · Apr 27, 2017

I second also getting a new belt while you're at it. It's a tough location for the lower bolt and it may be a little seized since there is a gap exposing the threads, but use a good box wrench and cheater bar and you'll get it off.

ZoSoIV

· #8 · Apr 27, 2017

football751 said:
Have you or anyone else used this alternator? That's an awesome price for a 200 amp alternator. That same seller also has a 250 amp for only $20 more! I think I'll send them a message and see if they can provide more specs like an amps vs. engine speed chart.

asked them at what RPM do you get 200 amps ...100% feedback I'm sure its a good one

football751

· #9 · Apr 27, 2017 (Edited)

ZoSoIV said:
asked them at what RPM do you get 200 amps ...100% feedback I'm sure its a good one

I just sent them a message and post the results when I get them. I'm more interested in the 250 amp version for just $20 more...seems like a steal to me.

This was the vendor's response:

Our bench shows 125 amps at idle and 250 amps at 1200 rpm.

norm356

· #10 · Apr 27, 2017

Just remember that when fitting a higher output alternator, and if you have actually added significant additional power consuming items to use that added power output, to also upgauge the ground wire from the battery to the body, and the power wire from the alternator to the battery, and to make sure those high current items which you've added which are higher than what your vehicle's system was designed with, have their own, dedicated power wires, from the battery.

This way you don't let the smoke out of any of your wires.

On the other hand, if you have not added anything of significant additional power draw, then fitting a higher output alternator won't really do anything for you (they only put out what is used). There's no down side, as long as it physically fits.

N

Reactions: 2

football751

· #11 · Apr 27, 2017

norm356 said:
Just remember that when fitting a higher output alternator, and if you have actually added significant additional power consuming items to use that added power output, to also upgauge the ground wire from the battery to the body, and the power wire from the alternator to the battery, and to make sure those high current items which you've added which are higher than what your vehicle's system was designed with, have their own, dedicated power wires, from the battery.

This way you don't let the smoke out of any of your wires.

On the other hand, if you have not added anything of significant additional power draw, then fitting a higher output alternator won't really do anything for you (they only put out what is used). There's no down side, as long as it physically fits.

N

Good reminder about doing the "big 3" upgrade, definitely on my list when I do the alternator. I don't have anything that draws a lot all at once, but I've added a lot of additional smaller items. Main thing is the ARB fridge. Higher output alternator will more quickly charge the battery out on the trails so that the fridge continues to run at night. Also since I have a deep cycle high capacity battery once depleted you run the risk of never getting it fully recharged since it can take so long to charge off the stock alternator.

thesilkiest

· #12 · Apr 27, 2017 (Edited)

Just wanted to add my 2 cents on the topic of a "better" alternator. I am a firm believer of certain things that you should not do to your truck. One of which is get a higher output alternator. These vehicles are tested extensively and in some cases corresponding components are spec'd to handle certain tolerances.
For example you can't just throw a supercharger in without upgrading certain components like fuel injectors, likewise with the alternator... who knows what the cap of the limit is on the fuses, wiring and stock oem battery is. Whether it will trip the ECU for an error code.

Toyota in this case has chosen components with the design and intention of harmonious balance and if the output... whether that be horsepower or electrical current is too high it can cause undue stress on other "stuff"

This is the world according to me, the youtube mechanic. Please feel free to educate me if I am way off here.

Also this happened when I changed my sparkplugs and alternator. And they were all stock components. After I checked my work and cleared the codes TWICE! There have been no further issues. If stock components can cause this? See pic.

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Reactions: 1

football751

· #13 · Apr 27, 2017

thesilkiest said:
Just wanted to add my 2 cents on the topic of a "better" alternator. I am a firm believer of certain things that you should not do to your truck. One of which is get a higher output alternator. These vehicles are tested extensively and in some cases corresponding components are spec'd to handle certain tolerances.
For example you can't just throw a supercharger in without upgrading certain components like fuel injectors, likewise with the alternator... who knows what the cap of the limit is on the fuses, wiring and stock oem battery is. Whether it will trip the ECU for an error code.

Toyota in this case has chosen components with the design and intention of harmonious balance and if the output... whether that be horsepower or electrical current is too high it can cause undue stress on other "stuff"

This is the world according to me, the youtube mechanic. Please feel free to educate me if I am way off here.

Also this happened when I changed my sparkplugs and alternator. And they were all stock components. After I checked my work and cleared the codes TWICE! There have been no further issues. See pic.

While I agree to an extent, you can add a supercharger if you also add new injectors (which the kits come with). So you can add a higher output alternator if you also upgrade the wiring and fuses and battery. I wouldn't throw a high-output alternator on an otherwise stock truck, agreed. But for those with high capacity batteries and extra power draw, we've exceeded the Toyota design limits already and are trying to make the rest of the system (alternator) match.

Definitely a strange error to get when using stock replacement parts.

Reactions: 1

thesilkiest

· #14 · Apr 27, 2017 (Edited)

football751 said:
While I agree to an extent, you can add a supercharger if you also add new injectors (which the kits come with). So you can add a higher output alternator if you also upgrade the wiring and fuses and battery. I wouldn't throw a high-output alternator on an otherwise stock truck, agreed. But for those with high capacity batteries and extra power draw, we've exceeded the Toyota design limits already and are trying to make the rest of the system (alternator) match.

Definitely a strange error to get when using stock replacement parts.

That is exactly what I was trying to say in a round about way. Thanks for confirming. Stepping outside what was intended by Toyota will in most cases require further upgrades and if not, may cause issues. I'm not willing to take that risk on an old rusty FJ

BTW those error messages have not come up for more than 4 months. I wonder if the ECU "learned" and was referencing the old standard of the failing alternator.
I know when I cleaned the MAF a reset had to be done also.

thane

· #15 · Apr 27, 2017

Just installed a Denso rebuild 130amp alternator and belt on a 2010 @ 92K. Voltage, measured with multimeter at the battery, was low and inconsistent (12.4 to 13.3) from the original alternator. Belt is cake @15 minutes, alternator was more difficult as the 2010 has a hidden metal bracket that is tough to get to. 2010 is definitely different part than the 07-09 one sent to me, had to send it back to amazon.

New one peaked at 14.1 volts, common lower voltage for modern autos to bring up fleet MPG, not good for your battery life as anytime spent in a non peak state allow sulfate to accrue. AGM batteries want more volts and an alternator voltage diode at the fuse box brought the voltage up to 14.5. Battery peaks quickly now, keeping the sulfate to a minimum.

(no smoke from my wires, or codes from the cpu :smile).

Winterpeg

· #16 · Apr 27, 2017

I put in a Mean Green high output alternator a number of years ago.
I've upgraded my main ground wire but not much else.

I replaced the alternator fuse with one from HBK which tells the alternator to give it a bit more voltage.

Other than that, I have not changed any other fuses or things with no problems.

Reactions: 2

sealevel

· #17 · Apr 27, 2017 (Edited)

football751 said:
Have you or anyone else used this alternator? That's an awesome price for a 200 amp alternator. That same seller also has a 250 amp for only $20 more! I think I'll send them a message and see if they can provide more specs like an amps vs. engine speed chart.

I have not used one yet. It's on my wish list. I would call them because I think you also need a different fuse so you don't overcharge the battery.
https://www.hkbelect.com/product/143-mk3-micro-blade-75a-electronic-fuse-version-2013/

FJtest

· #18 · Apr 27, 2017 (Edited)

First, check the ALT fuse to make sure it is not open, that it is fully seated in its socket, and that there is no corrosion at the fuse/socket interface.

These Denso alternators are extremely reliable, and normally the first thing to wear out are the brushes at 100-150K miles. You can pick up a replacement OEM brush module from your Toyota dealer for <$20, and the alternator will run reliably for another 120K miles.

The brush module is easily accessed through a cover plate on the rear of the alternator. It is recommended that you pull the alternator, blow out all the accumulated dust and grime, verify that the bearings are good, verify that the rotor slip rings are not excessively worn, and clean up the slip rings with 800 grit silicon carbide abrasive paper.

As long as you have not regularly submerged the alternator in muddy water, driven thousands of miles on extremely dusty dirt roads, or spray-cleaned the alternator with a 2,000 PSI pressure washer, the slip rings and bearings should be OK.

Here's a brush module with totally worn out brushes:

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norm356

· #19 · Apr 27, 2017

In response to the concern that installing a higher output alternator could harm your vehicle: as long as you upgraded the ground and power leads, and as long as you ran dedicated supply to your new current draw items which were outside the range of the original design, then it should all be OK.

One way to easily up gauge your power and ground leads is to add a second one parallel to the original, the gauge of the new one must be sufficient to handle the added current of all your added current draw items.

By doing these things your original vehicle systems will see no stress, and your new systems will all be able to work at their peak efficiency.

If you haven't added anything that draws much current then fitting a humungous output alternator to a stock vehicle won't harm anything, its output will not be any higher than the original alt due to no added current draw.

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