Electrical Inaccessible starter solenoid from wire tuck, what are my options for an alternator upgrade?

[AnthonyA1234]

So my alternator has begun to crap out on me. My car doesn’t make anywhere near enough power with the ac on and will die. My issue is, I did a wire tuck on the car and mounted the starter solenoid behind the fender. I’d like to do the 130 alternator upgrade but I won’t be able to route the 4g wire to the starter solenoid.

What would you guys do? Is it possible to run this alternator without the 4g wire upgrade? What about connecting the 4 g wire to the battery instead of the starter solenoid?

Or should I just get a factory replacement alternator? I don’t have any electric fans or big subs so I think I’d be ok… Or maybe there is a lower amperage size alternator I can get that is still higher than factory, but still low enough where I can leave all the factory wiring?

Those are all my options I can think of let me know which of those you guys is the best route I should take

 

[TOOLOW91]

You can run a 4g power wire Into the fender I’ve done multiple cars this way

You could also feed it to the battery and let the battery feed the solenoid still

 

[AnthonyA1234]

You can run a 4g power wire Into the fender I’ve done multiple cars this way

You could also feed it to the battery and let the battery feed the solenoid still

I looked at it and there’s no way I can get to the solenoid because of where I mounted it. I’d have to take the front bumper and fender off which I really don’t want to do.

So I can just run it from the alternator to the battery instead then with no other changes to the install? What kind of terminal would I use to connect the wire to the battery?

 

[AeroCoupe]

What kind of terminal do you already have on the battery? Picture would be best.

 

[AnthonyA1234]

What kind of terminal do you already have on the battery? Picture would be best.

Here’s a pic, it’s just the normal stock style I believe. I had to get a aftermarket longer positive one for my wire tuck.

 

[AeroCoupe]

Something like this if you do not want to cut the 12V+ cable.


View: https://www.youtube.com/watch?v=kaMH1mEGYkQ

 

[AnthonyA1234]

Something like this if you do not want to cut the 12V+ cable.


View: https://www.youtube.com/watch?v=kaMH1mEGYkQ

Nice, I’ll get something like that. LMR says to leave your factory power wire and add the upgraded one along with it, but I’ve read a lot in this forum say to remove the stock power wire and just run the single upgraded one.

I’m wondering, since I can’t reach my starter solenoid, would I be ok if I only disconnect the stock power wire on the alternator side and just terminate that end, leaving the solenoid side connected? Or am I ok just leaving the stock wire fully connected as LMR shows in their instructions?

 

[Mustang5L5]

I'd investigate why you are having power issues now first before firing off the parts cannon.

Stock fox even with the original 75A alternator should not be power-hungry with just the AC on. I'd put a multimeter on your battery and see what your voltage is. You may have a high resistance connection somewhere, or a battery issue, or something else.

I'd hate for oyu to throw a 3G on there and have the same issues. But, it could very well be that the alternator is tired and needs to be replaced

 

[AnthonyA1234]

I'd investigate why you are having power issues now first before firing off the parts cannon.

Stock fox even with the original 75A alternator should not be power-hungry with just the AC on. I'd put a multimeter on your battery and see what your voltage is. You may have a high resistance connection somewhere, or a battery issue, or something else.

I'd hate for oyu to throw a 3G on there and have the same issues. But, it could very well be that the alternator is tired and needs to be replaced

I just double checked and my battery had 12.6 volts and I did an amperage draw test and there were no amps flowing while the car was off. It’s got to be the alternator.

I just need someone to confirm if it’ll be ok if I just remove one side of the factory power wire from the alternator, leaving it on the solenoid since I can’t reach there, and capping off the side I disconnected so that I can be sure the install will work

 

[AeroCoupe]

You can simply disconnect the wire from the alt to the solenoid at either end and terminate it. Run a new 4 ga wire with a 125A fuse from the alt to the battery.

 

[AnthonyA1234]

You can simply disconnect the wire from the alt to the solenoid at either end and terminate it. Run a new 4 ga wire with a 125A fuse from the alt to the battery.

Great. I went ahead and ordered this kit from lmr. I noticed they say their wire comes with a 200amp fuse, should I swap that out for a 125?

https://lmr.com/item/SVE-17046K2/Mustang-SVE-130-Amp-Alternator-Upgrade-87-93-50L

 

[Mustang5L5]

Yes.

I do not know why they supply a 200A fuse with 4G wire. 4G is 100-125A max depending on length of run. Average fox is barely pulling 100A so this is usually not an issue

 

[Noobz347]

I'm going to leave this here in the case that you ever need it:

Amazon.com

I have one of these and I use a lot more than ever thought I would.

The only thing that beats a good crimp + dielectric grease + heat shrink is solder.

 

[AnthonyA1234]

You can simply disconnect the wire from the alt to the solenoid at either end and terminate it. Run a new 4 ga wire with a 125A fuse from the alt to the battery.

What’s the safest way to terminate a live wire like that?

 

[AeroCoupe]

Cut it flush and use a heat shrink cap. Then lay it back into the harness and tape it up.

 

[AnthonyA1234]

I did the install today. Check out how it came out. I paired the new alternator with a new upgraded bigger group 65 agm battery. The car should run great now I can’t wait to see.

I’m pretty sure I did it right but I just want to verify with you guys. In that last pic is the 4ga block to frame ground I added. I went from the factory negative battery cable ground location on the drivers side engine block, to the top of the sway bar bracket. Is this a proper ground for this?

 

[Noobz347]

750/120 ... Yep, that's a pretty big battery.

Your grounds should be just fine. If you ever start detecting a noise in audio systems etc... , go back change the last ground you made or modified.

I have successfully installed a ground-loop in my 86 that took me a bit to find and diagnose. I had a thousand, "You need new plugs with resistors!" responses.

 

[Mindseye007]

So my alternator has begun to crap out on me. My car doesn’t make anywhere near enough power with the ac on and will die. My issue is, I did a wire tuck on the car and mounted the starter solenoid behind the fender. I’d like to do the 130 alternator upgrade but I won’t be able to route the 4g wire to the starter solenoid.

What would you guys do? Is it possible to run this alternator without the 4g wire upgrade? What about connecting the 4 g wire to the battery instead of the starter solenoid?

Or should I just get a factory replacement alternator? I don’t have any electric fans or big subs so I think I’d be ok… Or maybe there is a lower amperage size alternator I can get that is still higher than factory, but still low enough where I can leave all the factory wiring?

Those are all my options I can think of let me know which of those you guys is the best route I should takemy 1991

My 1991 5.0 LX Coupe has a charging system better than the energizer bunny, lol, with this installed.
https://lmr.com/products/sve-200-amp-alternator-upgrade-86-93-mustang