Need Alternator/ Wiring Help ASAP!!

[sax_man]

Okay guys I'm completely lost and so is the shop. Anything you can give to would be helped. Just let me say I think I have two separate but related problems. Sorry in advance for the long post, but I really need help.


Started in early June. My battery died, so I went to get it replaced. The new one died about 2 weeks later. Replaced it again, and tested the alternator to find out it was bad. Got the alternator rebuilt at a local shop, and they told me that the regulator on it was shot.

Installed the rebuilt alternator it and the battery kept dying. Took it to a shop that I trust, and they found that the alternator was only putting out like 12.3-12.4 volts on the car. Had them take the alternator off, and went to get it tested on a bench. Took it back to the shop that rebuilt it, and it passed on their bench. Took it to Advance Auto, and it passed on their bench, but was only putting out 13 volts:dunno:. I felt like that was really low, but I figured it was good enough, so I thought I might have a wiring/ grounding issue.

Went to go put the alternator back in the car, and the shop told me that one of the studs that holds the alternator bracket to the block was stripped so the whole bracket was moving. We thought that maybe this was making the belt slip and lose tension which would cause the low output from the alternator. They had to take off the water pump to extract the stud and put a helicoil in. This did not solve the problem, and the alternator was still putting out 12.x volts.

At this point I say F it and decide to get another alternator. The shop installs it, but then calls me to say when they started up the car after the install the battery and brake lights (and some others, I can't remember which ones) came on and stayed on, so they were thinking I had a wiring issue. I then get another call that says the alternator is having voltage spikes of 18 volts, and that they're worried that stuff is going to start frying.

They also seem to think that the ECU was causing this problem as the ECU tells the voltage regulator on the alternator how many volts it needs to be putting out. They tried swapping in a 95 eprom that they had laying around, but it wouldn't even start the car. Unfortunately there are on turbo ECU's locally that I can swap out to test with. I'm okay with swapping out my ECU because I want a flashable one anways, but could the ECU be causing this problem?

After all this, the 10a gauge fuse under the dash blows out every time they start the car. And when they hit the brakes, the battery and brake light come on the dash.

On top of all that while they were trying to take out the ECU they found what appears to be a mouse nest underneath my center console by my shifter. This is making them think that maybe I have some chewed wires that are shorting out.

At this point they're just going over wiring diagrams trying to figure out what is up

Basically,

Are all these problems related?
What can be causing my voltage spikes?
What should I look for with the fuse that keeps blowing and the random dash light?

I want every suggestion you have. I don't care how off the wall or obscure it might be

Thanks.

 

[gofer]

1. Your car wouldn't start using the '95 ECU because your running a '97-'99 CAS with it, you need to swap the firing order of the spark plug wires.
   
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2. I don't know what shop your working with but if they aren't a Mitsu specialist (like the dealership) then they don't qualify to work on a DSM in my opinion, especially if its complicated which your issue is.
3. Go to a local car parts store and get a '97 Galant A/T alternator, its 90A instead of 60A and bolts into place. Quit having all these B.S. shops rebuild your alternators and troubleshoot your charging problems, your chasing your tail.

 

[sax_man]

I know about the CAS. And he remebered after he hooked it up. The owner of the shop has a built gsx running a 50 trim, and they've done good work for me in the past. And I thought 2g alt's were 75a?

And thanks for not answering any of the questions I asked.

 

[gofer]

Are all these problems related?
What can be causing my voltage spikes?
What should I look for with the fuse that keeps blowing and the random dash light?

Thanks.

1. Yes.
2. Your alternator overcharging the battery.
   

   After all this, the 10a gauge fuse under the dash blows out every time they start the car.

3. There are a few 10A fuses under the dash, knowing which one it was I could possibly go through a wiring diagram for you.

Your Welcome.

 

[sax_man]

On the fuse box it just says 10a- gauges. I will try to find a pics of the box so I can point out which one it it specifically. Thanks.

And obviously the alt is overcharging. Did you read my op? Can a problem with the ecu cause this? Aside from grounds, shorts, and bad wiring what other things should I be looking for?

Middle row, 4th one down. Gauges. This is the one that blows when the car is started.

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I believe this is a 2g diagram.

 

[gofer]

There is a voltage sense wire you can check, its at the alternators connector pin 2 (red wire). The wire runs from the headlight circuit to the alternator to tell the alternator the cars operating voltage.

Personally, I think its the shop's rebuilding the alternator causing it to overcharge your battery. I'm not knocking your trusty shops, however the regulator in the alternator should still have an upper limit even if its blind to what the voltage sense line is telling it. NAPA sells brand news ones (not rebuilt) and a '97 Galant A/T is 90A instead of 60A. (The OEM 2g is 75A but if you get them rebuilt from AutoZone, etc. etc. they are 60A)


I'll dig through some wiring diagrams and see whats on the circuit to that "gauges 10A" fuse that keeps popping.

 

[sax_man]

I am no longer using the rebuilt alternator. I am using one the shop ordered. I suppose it's possible the voltage regulator on the shop ordered alt is is bad as well...

I will look into the galant alt too. Does it bolt up with no modification required?

And thank you for looking at the diagrams. I'm wondering if there's a relay or something on there that's bad.

 

[gofer]

No modification whatsoever for the Galant alternator, it bolts up like a 2g and plugs in like a 2g. I like helping people, sorry if we had a rocky start to this but we'll figure out the problem but until then, as I'm sure you know, over voltages can cause ECU damage so don't drive it!

 

[sax_man]

Oh I know. It's not leaving the shop till this is fixed. And I appreciate the help.

Does the galant alt it use the same belt as a 2g as well?

Can the ECU be causing this?

 

[sax_man]

Gofer did you ever find anything?

 

[twister7]

It could be ecu related, but you know you have wiring issues start there at this point, check the wires that are taped up that run from the lh driver side out and above the front lh side wheel, and untape them and look,i have had one spyder and one gsx in the last month that had a wire or two cooked in half in that harness corrosion seams to set in and the wire breaks in half both cars had the wires still wrapped in what looked like the factory tape job, i guess it is from age!

 

[VETTE_50_TH]

The galant alt looks just like a regular. Its the internals which change the amount it puts out.

 

[sax_man]

Just got back from the shop. The under dash fuse box got toasted during one of the voltage spikes, so that probably answers the blowing fuses/ dash lights question. Obviously the car isn't going to be started till we figure out what's up.

The alt is coming back off to go on a bench, and I'm hoping that that's the problem. (Yes yes I know that probably should have been the first thing that got tested) And twister, I can't see the image you attached.

Thanks for the help guys!