88 4Runner 3vze: Replace the voltage regulator or just get a new alternator? (1 Viewer)

[razorhack96]

So, I've been dealing some electrical issues resulting in the ignition not wanting to turn the starter over intermittently. And then a couple of weeks ago, three lights lit up on the dashboard all at the same time: AT Temp, Battery, and Brake. Which is odd cause there's not much in common with any of those.

Then a cold snap hit us here in the OKC area and 4Runner was refusing to do anything. I thought it might have been a bad EFI/Starter Relay as I did recently replace it. So, I picked up a new one, and as I was turning the ignition, I noticed the dome light dim. Odd. Checked the battery. Low on charge and the system voltage was only 11v. No wonder the ignition and the EFI/Starter Relay was not working as they need 12v at a minimum to work.

That led me to think that the issue was with either the alternator or the battery. But both are fairly new. Battery was purchased last July and the alternator was replaced about 5 years ago when the engine was rebuilt and probably only has a few thousand miles on it, but did sit for a few years before I acquired it. So that lead me to thinking it might be the voltage regulator.

I headed to one of the autoparts store and did find one that had the equipment to perform a load test on the battery so we could rule that out. Battery passed of course. They were also able to test the alternator with the same tool and the alternator passed, but the voltage regulator did not. So, now I'm looking around for new voltage regulator. But all the ones I see online don't look like the one I thought was in my 4Runner. Which has me wondering what this block with fins behind my fusebox on the passenger side of the engine bay is.

So after doing some more digging, I've now figured out that Toyota (I'm a noob to Toyota), has the voltage regulator inside of the alternator! So after looking at the cost of a new voltage regulator and an alternator, there's not much difference in price. Depending on brand, a rebuilt alternator is cheaper than the voltage regulators that are available. So here are my questions:

• Replace the voltage regulator or replace the alternator? Cost wise, they're pretty close in price.
• What is that part behind my fuse box with fins connected to the harness with the same 3 prong plug as the one going to my alternator?
• If a I buy a new alternator, is it worth finding a unit with more amp output from a different Toyota model? And does anyone know of one off the top of their head that is nearly bolt in?
• I've heard of people switching their older Toyota's over to a 1 wire GM style alternator. Anyone done that?

 

[aztoyman]

All the Toyota alternators of this vintage that I've seen have the regulator built in. IDK how your parts store tested them separately.

If you have a multimeter you can test it yourself while the engine is running. Probably YouTube videos out there if you have any questions.

You can check your battery as well.

Make sure your cables and terminals are clean.

If you're sure the alternator is bad and don't want to rebuild it, get a reman or buy a new one if you prefer.

Good luck with it and please follow up.

 

[vipergrhd]

That part on the picture is not a regulator it looks like a battery isolator for a dual battery set up. Your regulator is inside the alternator, you could buy it from Toyota if you want good quality or take it to an electrical shop that works on generators/alternators etc.

This is a typical Toyota/Denso voltage regulator.

 

[gnob]

if you have a denso/oe alt, id just service it and move on. brushes and vr are cheap

 

[pappy]

if you have a denso/oe alt, id just service it and move on. brushes and vr are cheap

Too many alternators are junked when that is all they need. Shoot, most of the time you can drop in a set of brushes and call it a day. Same with starters ... contacts, plunger, and done.

 

[razorhack96]

if you have a denso/oe alt, id just service it and move on. brushes and vr are cheap

If it had Denso/OE alternator @gnob, that would be an easy decision, just replace the voltage regulator. I'm learning quickly that any Denso parts should not be suspect or replaced without sufficient testing.

Too many alternators are junked when that is all they need. Shoot, most of the time you can drop in a set of brushes and call it a day. Same with starters ... contacts, plunger, and done.

Totally agree @pappy. One thought is to buy another complete alternator, and then when I have the spare funds, replace the voltage regulator in this remanufactured unit from Mexico that was probably and auto parts store sale, which is typically a price point and high margin return item than a quality part. Obvious on the latter in that voltage regulator failed. But having a spare alternator might not be a bad thing. But then again, Toyota used this alternator on a lot of vehicles from that era and supply should be available for the foreseeable future.

it looks like a battery isolator for a dual battery set up.

I don't think it is a battery isolator for dual battery set up. It's a Denso unit, but the part number is a bit faded to tell for sure. And it's clearly factory tied into the harness. I doubt the factory had a dual battery setup.

 

[pappy]

I don't think it is a battery isolator for dual battery set up. It's a Denso unit, but the part number is a bit faded to tell for sure. And it's clearly factory tied into the harness. I doubt the factory had a dual battery setup.

Correct, not a battery isolator. That is the resistor pack for the fuel injectors.

 

[ntsqd]

After having the VR on my '84 22R fail repeatedly, two of them within a year, I put a Delco CS130 on Patch. It was not a simple swap, I made the brackets because there was no kit. I do not use one wire alternators, I wire them correctly. In that truck I used one of the failed regulator's pigtail to plug into the truck's harness, and then made up the adapter harness to connect to the alternator.

On my '88 V6 4rnnr I did the 100A MR2 alternator swap. That is almost a bolt-on. It does bolt on, but some creative clearancing needed to happen so that I could easily get the belt on its pulley.

 

[clx16]

I like getting my alternators from the junk yard. I get new bearings and brushes if they need them and clean them up. I have not had good luck with after market alternators and I don't trust reman units unless I am replacing the cheap stuff inside back with good stuff.

 

[razorhack96]

Okay, I acquired a whole new alternator over just replacing the voltage regulator. I chose a new alternator over just replacing the voltage regulator, mainly because the cost was about the same. Picked up a new AC Delco alternator over a remanufactured unit. I know... it's not OEM or even a popular Asian brand, but AC Delco in my experience has produced many fine alternators, both domestic and foreign.

As a result, all the lights on the dash went out after putting the new alternator in. I'll keep the old alternator and get another voltage regulator when I have the spare funds. That way I have a spare alternator if I need to put another in.

The old alternator is on the right in the below picture:

The AC Delco has a better fit an finish the old one which was a remanufactured unit.

 

[aztoyman]

Glad you got it fixed. Thanks for following up.