Resolved 2G Over charging alternator?

[Bedicine]

Hoping someone would be able to chime in on some issues I’m having.

Car was having issues the other day when I turned on the high beams that all of the lights went out and car started idle surging. We remove the alternator and tested the battery. Battery is brand new and no issues shown on the tester.

Alternator was fried, new 90amp alternator ordered and installed, car fires up no problem but still getting an idle surge and voltage jumping to 17. I’ve attached a video for reference at idle. Battery light is also still flashing.

Alternator relay was also replaced, starter is sometimes clicking and it’s new (wondering starter relay) but could this be a symptom of a burnt spot on my ECU causing the voltage to spike and battery light not going off?

When the voltage spikes the rpm’s are also raising up to 1700, when it drops back down the car idles fine

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[Bedicine]

When you bolted the fuse into the engine bay fuse compartment did you confirm the wires are still attached to the bottom where you bolted the fuse in?

-Daniel

Like making sure none of the wires pulled out the bottom of the fuse box? Everything is still connected.

 

[19Eclipse90]

Sorry, there’s a lot of things said and tried here and trying to aim through to get the gist just doesn’t work.

From the sounds of it, seems you have the necessary connections in your circuit. Have you tried wiggling the pins in the alternator connector, pushing and pulling in them to make sure they are firmly in position?

Without the battery hooked up, have you checked continuity of the sense wire (pin 2) to the socket of the headlight fuse?

Changed the fuse today to 100aml and made sure there was a good connection from the sense wire at the alternator to the fuse box which goes in at the headlight fuseable link. ECM link mentioned there should be no connection from here to the battery, the other side of the fuseable link has the eyelet that runs to the battery and I’m assuming this is where the sense wire is pulling power readings from.

Your assumption is correct. One of the reasons I asked about that cable is that would’ve been the incorrect location for the alternator power wire to go - again, just trying to sort through everything.

I’m assuming you’ve verified voltage with a meter, not just relying on the digital volt gauge?

 

[Bedicine]

Sorry, there’s a lot of things said and tried here and trying to aim through to get the gist just doesn’t work.

From the sounds of it, seems you have the necessary connections in your circuit. Have you tried wiggling the pins in the alternator connector, pushing and pulling in them to make sure they are firmly in position?

Without the battery hooked up, have you checked continuity of the sense wire (pin 2) to the socket of the headlight fuse?


Your assumption is correct. One of the reasons I asked about that cable is that would’ve been the incorrect location for the alternator power wire to go - again, just trying to sort through everything.

I’m assuming you’ve verified voltage with a meter, not just relying on the digital volt gauge?

For the sense wire on the diagrams i only see it going into the bottom of the headlight fuse and then it going no where from there. That fuseable link is then going to the battery from the two white pair.

 

[19Eclipse90]

Right. It’s sensing the voltage at the headlight fuse, supplied from the battery, which then allows the regulator to do what it do. The sense wire is not going anywhere else past the headlight fuse.

I do not have an electrical background like @luv2rallye, but I can reason that moving the sense wire from the headlight fuse and, instead, run it directly to the battery wouldn’t be an issue.

 

[Bedicine]

Right. It’s sensing the voltage at the headlight fuse, supplied from the battery, which then allows the regulator to do what it do. The sense wire is not going anywhere else past the headlight fuse.

I do not have an electrical background like @luv2rallye, but I can reason that moving the sense wire from the headlight fuse and, instead, run it directly to the battery wouldn’t be an issue.

Ok so I have that hooked up and still having issues. I can try a different brand alternator. Maybe the car doesn’t like the 90amp? I did go to a 100a fuse from an 80 and it didn’t do anything.

I’ve noticed my starter now is t working all the time, I go to turn the key and it does a single click, was a brand new starter but wondering if maybe these two issues are connected?

Anything I should look for with my battery relocation that may have caused both of these issues

 

[19Eclipse90]

It could very well be the alternator.

As I mentioned before, it sounds like everything is where it needs to be for this to work.

Nothing new here, but:
Double check all grounds and make sure they are going to unpainted surfaces.
Make sure all connections are tight and corrosion free.
You mentioned a circuit breaker near the battery - is voltage the same on each side of the circuit breaker (from battery, to each leg)?
I don’t know what you have now for a sense wire but with the plug disconnected from the alternator, you ought to have battery voltage on the sense pin (pin 2).
Since you’re concerned, check continuity between pin 4 (green wire) of the alternator plug to ECU pin 41.
In the same way, check continuity from pin 1 (white wire) of the alternator plug to ECU pin 33, knock those off the list.

As I understand the function of the generator relay, it’s not even being used since your charge light (battery dash light) is not burned out.

Things continue to point at the voltage regulator as faulty.

For general knowledge of the forum, per the 1997 FSM, the automatic 4G64 cars came with a 90A alternator, so there’s not some big mystery there.

 

[Pjj]

Silly thing to ask but,

on your ground stud on your alternator, do you have the factory wiring harness ground on it? if it doesnt have a factory harness ground put a ground wire from that stud to the frame rail of your car and see if it does anything. when i did that it got rid of majority of my electrical gremlins with ignition etc

 

[dwb]

It could very well be the alternator.

^^^this
You could at least bring it to your favorite parts store and have them test it. Is this the same alternator that was over charging and now not charging?

As far as your starter issue, is it anything like this? https://www.dsmtuners.com/threads/1g-intermittent-starter-issue.544123/

 

[TerminalTalon]

That’s why my comments are going through all of it again especially voltage out of the alternator. Anything but Denso or OEM I do not trust.

 

[Bedicine]

So for the 4 alternators I’ve had (different manufacturers), a mixture of new and reman I’ve taken them out and had them tested and it shows the regulators are blown. Only other thing I can do is buy a new one (denso) have it checked before it goes in the car, they all say working but we know the bench test doesn’t mean as much. Then instal it and see if the car blows it again. I’ll check voltages tomorrow across the board including the circuit breaker at the battery. I’ll recheck the ground from the battery which I have running up to the starter ground bolt on the transmission. Then have a grounding kit on various points of the engine with them branching from there.

My transmission case is painted but the bolt is threaded through, think that could be causing the ground issue?

I do have another starter here I can try as well to see if maybe that fixes one issue but weird they’re both having problems, high beams flicked occasionally but I attribute this to the low voltage when it’s not charging

 

[Bedicine]

Also I’ve attached a photo showing how the main feed from the trunk (positive) feeds out to everything. Large 0/1 is the positive cable and the other 0/1 with shielding is going directly to starter

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[Bedicine]

Took the starter ground off which I think I had in the wrong location (one on the transmission beside it). Took the flapper wheel to it and cleaned it all and car starts up easily now. One issue down.

Alternator still not charging, this morning I started it and it was at 13.3, turned it off and started it again and it was down to 11.5, went for a 20 minute drive and it stayed roughly at 11.3 and battery light came back on. Going to check through it today.

What are the thoughts about running the alternator off the 0/1 battery feed instead of the separate 4gauge feed I have going to the battery?

 

[Bedicine]

Looks like the sensor alternators are back ordered in Canada currently which is unfortunate.

Took the volt meter to the car and the battery was running at say 11.6, the in and out posts on the circuit breakers had the same. Went to the power block in the engine bay and same thing. Starters acting up again, thinking this maybe dead after all these restarts the past few months while troubleshooting. Ground helped but still having issues.

75 alternator come this week and hopefully my replacement plug does. Curious on everyone’s thoughts on the trunk relocation if I need a seperate feed for the alternator like I currently have or can jt go off the majn battery feed?

Any comments on overall fuse and circuit breaker sizes with the relocation, doubt it’s causing an issue but just want to confirm

 

[Bedicine]

Once again swapped the alternator, changed the actual pigtail with a new one and still same result of 11.6 volts.

 

[Bedicine]

Got it fixed finally. Thanks everyone

 

[curt-s]

How? Can you post up the solution so others can look up if/when they have the same

 

[Bedicine]

It's hard to describe but if you're doing a battery relocation and bypassing the fuse in the fusebox (underhood) you need to make sure that accessories and such aren't pulling from the backside of that fuse as its no longer getting power. typically the power wires is those two white wires and feeds this location of the fuse box then connects to the alternator. with this point not being used there is still the portion of the harness that gets to the alternator that needs to be connected correctly. Still not sure how 5 alternators were all DOA but car runs great now with a 75amp reman. appreciate everyone's help