420A 2GNT Charging Problems

[Lsjuice]

I have a 420a (95 Eclipse GS manual) and I’m having charging problems I replaced the battery and the alternator. I’m thinking the PCM might be faulty or something. If I change it do I need to get it reprogrammed or something or just installed and call it a day?

I’m really new to this and I can’t find much info.

My problem is charging, I replaced the alternator, the battery, and my next step will be the PCM, I read the Electric Voltage Regulator might not be working and it’s integrated into the PCM. Can I just change that or do I need to change the whole PCM?

If so, do I need to get it reprogrammed to my car or will it just work as normal?

 

[Dericsh]

Hi, welcome to the forum.

No need to post the same question in multiple threads, trust it will be seen and answered as soon as someone can help.

To answer your question, no, there is no reprogramming involved in swapping ECUs.

However, let’s talk about what the exact problem you are having, and what have you done to diagnose it. Do you even know if the new parts you got are working correctly? Is the charging system indicator light working on the dash?

 

[Lsjuice]

Sorry about that, I have changed the alternator even though my old one was working. I changed the battery I'm thinking the PCM is not working, the light in the dash works my battery isn’t charging to the 13-15V it should when working I’m thinking about doing the ECU replacement but what about a external voltage regulator? I did it in a keep once and it worked maybe It will work?

 

[Dericsh]

I don’t see any mention of the ECU in the 95 wiring diagram for the charging system. You can also see that it states that the voltage regulator is part of the alternator. Possibly I’m missing something due to the 420A engine.

Have you checked all the fuses and fusible links listed in this diagram?

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EDIT: see Post 6 for a better diagram from the non turbo manual.

 

[spyderdrifter]

Just install the PCM/ECU. The voltage regulator is a part inside the alternator, and it can be replaced if you know how to do it right.

 

[steve]

On the 420A cars the voltage regulator is inside the PCM unlike the 4G63 and 4G64 based 2G's. At lease this is the case with the later versions. I don't have my full 95 and 96 manuals here.

As far as I know, which isn't much when it comes to 420A cars, as long as you stay within the same model year and car type (emissions and transmission) you can swap ECUs.

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[BLACK'98DSM]

What is the voltage reading from the battery terminals while idling? What about directly from the alternator?

 

[Lsjuice]

Update here, I decided to buy an external voltage regulator and wire it to the alternator, it worked so thank y’all for the information