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]

I do, this alternator has a separate ground in it as well as through the bolt that goes to the block

Talking to the team at ECM they mentioned the sense wire shouldn’t go straight to the battery but go through the electronics (I.e fuse block) then to the battery

 

[CanadianTalonTC]

My $0.02

The bucking/drive issues seems in line with voltage issues unless you have properly setup the injbatteryadj table for link as your injectors perform differently at each voltage.

As far as the ground, unibody cars are notorious for being tough to ground vs a solid steel frame running through the entire thing. I personally would bring a ground direct from the battery to under the hood then disperse it to the block and such but I don't believe that it will fix this issue. Definitely best practice though.

You are from Canada, is your car a Canadian spec car or imported? If it was Canadian spec as far as I know, it should have had a 90a alt from the factory for our market (DRL's required). If your old one worked, the new 90a shouldn't be making much of a difference. As far as the issue you are currently having, after 3 alts that are not working out of the box I'd be sourcing a known good OEM even to borrow from a friend for a day to test it. If it works fine, back to the auto store and complain some more.

Alternatively, take your alt down to somewhere that can rebuild it for you to OEM spec again.

The wire you moved to the trunk, how large is it? I'd question the voltage accuracy from it being 10'. 12v so sooo bad for voltage drop. I'd recommend leaving it the factory way tied into the headlight area (which may not be working properly if you have removed some of the fuses and such).

Now that I'm writing this I am questioning whether there was an issue present that fried out your old genuine Mitsubishi alternator/regulator masked such as poor grounding, or that small wire being disconnected somehow etc that we are now seeing on a poorer quality alt.

 

[Bedicine]

The car was a shell when I bought it so not sure of the original alternator but it started life as a Canadian eagle talon so assuming it was a 90amp then which is what I have installed. I don’t have running lights anymore and will run the ground to the front.

Sense wire is 16gauge, assuming I run that into the fuse box which then goes to the plug on the alternator and hopefully this fixes it? Alternator power cable is 4gauge running to inline fuse and then dedicated circuit break on battery box in trunk. Car was recently tuned with Reza and runs great regardless of the battery issues so I don’t think it’s anything to do with the tuning

 

[CanadianTalonTC]

The car was a shell when I bought it so not sure of the original alternator but it started life as a Canadian eagle talon so assuming it was a 90amp then which is what I have installed. I don’t have running lights anymore and will run the ground to the front.

Sense wire is 16gauge, assuming I run that into the fuse box which then goes to the plug on the alternator and hopefully this fixes it? Alternator power cable is 4gauge running to inline fuse and then dedicated circuit break on battery box in trunk. Car was recently tuned with Reza and runs great regardless of the battery issues so I don’t think it’s anything to do with the tuning

I found another members post that mentioned that had had theirs fail after pulling a headlight fuse since they removed lights and ultimately found all factory fuses needed to remain there for it to work properly. Are any of the other fuses or relays pulled out?

As far as the tune, I have no doubt they are great but the injbattadj is needed to be completed based off a sheet supplied by your injector manufacturer so many people leave it stock. Wasn't trying to dig or anything. I don't think that the tune caused it at all, just the drivability issues you mentioned are in line with this issue and injectors.

 

[Bedicine]

Does anyone have a photo to show how the sense wire comes out of the fuse box and connects to the battery so can mimick it?

 

[Bedicine]

This is the bottom side of the fuse box at the headlight fuse (40). Assuming the small red wire is the sense wire from factory that goes to the alternator plug. Looks like it goes in then comes out in a wire cable

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[CanadianTalonTC]

Looking at my FSM, it shows pin A-02 (sense pin) going to "fusible link" and that is it. I recently rewired my car so my photos will not apply but if I remember correctly, the 4 white wires (2 bundles of 2) going from your battery to the fusebox has the sense wire attached to these at a joint underneath the lower fuse box panel.

Remove your lower side of the box my popping those clips off around the lower perimeter. It's super easy to break the clips so be gentle! Once all the little clips are popped the bottom will come off. Trace those two wires and you'll find they run to the red circle under these fuses. There are two eyelets (each eyelet has 2 wires i believe) and they are attached to the bus bars for those fused sections. Follow them back and you should find one of them has another (I think red) spliced into it near-ish to the entrance of the fuse box.

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[Bedicine]

I don’t have the two sets of white wire anymore as I have the battery relocated and ran all new lines

 

[CanadianTalonTC]

I don’t have the two sets of white wire anymore as I have the battery relocated and ran all new lines

Then you should be able to just wire a piece of primary wire to those with an eyelet or something.

 

[Bedicine]

Have my sense wire run from the plug to that eyelet and then to the battery and leave the mini fuse in place as a precaution? Makes sense

 

[CanadianTalonTC]

Have my sense wire run from the plug to that eyelet and then to the battery and leave the mini fuse in place as a precaution? Makes sense

Factory doesn't even have a fuse, but I'm sure that would work fine. Any short run from a clean 12v source would work fine. 12v just has annoying properties compared to A/C over longer runs.

 

[jed344]

So if i read this right your alternator charge wire is 4 gauge and runs to the battery in truck then back up to fuse box? We have done many battery relocates and even my buddy has built a few totally custom harnesses from scratch. The 4 gauge is fine from ALT but regardless if fuse box was still in engine bay or in glove box we then always ran that to a distribution block under the hood that then also supplies the fuse box, starter, and battery even if in the back. We always used 0-2 gauge for the power cable to trunk for battery and left the sense wire at the location it was factory and its always worked for us this way.

 

[Bedicine]

So if i read this right your alternator charge wire is 4 gauge and runs to the battery in truck then back up to fuse box? We have done many battery relocates and even my buddy has built a few totally custom harnesses from scratch. The 4 gauge is fine from ALT but regardless if fuse box was still in engine bay or in glove box we then always ran that to a distribution block under the hood that then also supplies the fuse box, starter, and battery even if in the back. We always used 0-2 gauge for the power cable to trunk for battery and left the sense wire at the location it was factory and its always worked for us this way.

The alternator has its own dedicated cable that goes into a 100amp quick connect fuse in the bay and then a circuit breaker before feeding into the battery positive. I have a dedicated 0/1 gauge wire going from the battery into a circuit breaker before making a run up to the engine bay which then goes into a distribution block and goes out to fuse box and other items.

 

[Bedicine]

New alternator and still having the battery light come on when I touch the gas. Power doesn’t seem to be dropping but it’s also not charging. Video and picture attached of the quick wire I made to the light circuit from the alternator that then goes to the battery

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[Bedicine]

Photo of the temp connector

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[Bedicine]

Is there a possibility this could be caused by a broken wire that goes to the ecu since that sends the signal or would this all be related to the sense wire?

 

[TerminalTalon]

Verify battery voltage on the output circuit (white) at all times.
Verify battery voltage with the engine running on the red.
Ground the blue wire at the alternator to see if the alternator charges. If it does the alternator is fine.
If it doesn’t verify the blue wire to the PCM is not open. If it is not replace PCM.

 

[Bedicine]

Verify battery voltage on the output circuit (white) at all times.
Verify battery voltage with the engine running on the red.
Ground the blue wire at the alternator to see if the alternator charges. If it does the alternator is fine.
If it doesn’t verify the blue wire to the PCM is not open. If it is not replace PCM.

I thought the turbos don’t have PCMs? I just had the computer checked by ECMTuning, sent it to them for testing and there was no issues they could find. It’s the 5 brand new alternator and all having the same issue. Different manufacturers

 

[TerminalTalon]

I’ve been in the field for a decade now. A lot of aftermarket parts are complete junk out of the box but simply because people think they have saved money they keep them in business. I’d check the alternator, fuses, wiring again.

Honestly it’s Denso or bust for me if I didn’t trust a local rebuilder. It’s redundant to do the job X amount of times but I’d still check everything again.

This is for a 97.

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I thought the turbos don’t have pcms? I just had the computer checked by ecm, sent it to them for testing and there was no issues they could find. It’s the 5 brand new alternator and all having the same issue. Different manufacturers

ECM/PCM
Same thing
Engine control or powertrain control units.

 

[Bedicine]

I drove the car today for 30 mins, voltage stayed at 11.5 the whole way, would dip down then come back up. Battery light was on the whole time. Can’t get over 11.6 even on a full charge once the car is on. Battery has been tested and is fully charged.

Could it be the 90amp alternator, broken wire, poor ground or even the relay that goes to the battery light which is also new?

I have a 90amp alternator, drl disabled but the fuse from the alternator to the battery is an 80amp and then goes to a circuit breaker and then to the battery all via a 4 gauge wire

 

[Bedicine]

Ran a 0/1 ground from the battery up to the front and still having the same issues. I charge the battery and it starts at 13.4 then after a 15 min drive it’s down to 11.6,

I’ve ordered a new pigtail connector from ohm for the alternator. Going to try changing the alternator fuse from 80 to a 100 as that what factory is and maybe that’s partially tripping with the 90amp alternator

 

[Bedicine]

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.

Still having the same issue. Can’t get above 11.7v with the car idling and all accessories off. Battery light is still on.

Any other things to try while I wait for a new pigtail?

 

[99dsmer4g63]

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

 

[19Eclipse90]

Photo of the temp connector

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You’re saying this wire cable coming into the top of the fuse box is the “replacement” for the two white wires coming from the alternator?

 

[Bedicine]

You’re saying this wire cable coming into the top of the fuse box is the “replacement” for the two white wires coming from the alternator?

No that was my temporary sense wire. Was coming from the alternator plug to that post then back to the battery. Since eliminates that and just have the sense wire running into the bottom of the headlight fuse like factory.