3g alt wiring questions. long with lots of pictures.

yeah i agree with 04sleeper. at first i left the factory wire in after i disconnected it and ran the new power wire. then i noticed it had arch welded itself to my strut tower! :eek: needless to say, i was quick to pull that **** out. here's what the factory power wire looks like....a mess of BS.

here's where the yellow wire spliced into it then went to the solonoid:
View attachment 358875
View attachment 358877

here's the 2-1 union. :nonono:
View attachment 358879
 
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The yellow wire (sense circuit) needs to see battery voltage one way or another. He's kept the wire remotely located the way he did it.

IIRC, the wire in OEM form is connected on the alt side of the circuit protection (the alt sees this circuit fall to 0 volts if the link for the charge cable blows).


The Yellow Wire is on the D Plug is it not? I am probably just missing something simple:shrug:
 
Where are most of you getting your 4g wire at does radio shack sell it by the foot.

Auto audio shops will have it.


See WWW.partsexpress.com for the fuse & fuse holder.
Fuse @ $3.90 each (need one) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=071-952

Fuseholder @ $5.80 each (need one) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=263-630

4 gauge black wire @ $1.25 a foot (use string to lay out routing & determine length) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=100-196

4 gauge red wire @ $1.25 a foot (use string to lay out routing & determine length) http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=100-194

4 gauge ring crimp terminals (package of 5) $3.25. http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=095-584

3/4 “ Black heat shrink tubing, 4ft length, $3.56
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=082-058

3/4 “ Red heat shrink tubing, 4ft length, $3.56
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=082-064
 
The only thing I see is why is everyone using 4 gauge when its only rated for 105-125A. I thought the 3g was a 130 amp alt, and the other thing is when I look at the wire cost its $1.95 FT.

Your wiring chart is off or you're planning on running 100' of 4 gauge cable. The particular cable I used was rated for 135 amps over the distance I ran it.

Some cars with 3G's stock come with 6 AWG from the factory.

I'm thankful for the links Jrichker provides. He probably doesn't have time to update them every time prices go up.
 
So I cant say anything about someone who writes something wrong. dude give me a brake its not like i said anything bad just stating the facts. If it makes you happy thank you so much Jrichker. Next time something is wrong i will just go along with it.

While inquiring about wrong info, did you figure out your wiring chart issue? If not, we're here to help clear up any questions you might have. We'd want you to feel comfortable with your wiring choice.

I didn't mean to sound rude - I interpreted your earlier post as being ostentatious and perhaps it was not meant to be so. Prices going up every 2 weeks is something we're used to - most of us know to expect it.

Good luck with your install.
 
So I cant say anything about someone who writes something wrong. dude give me a brake its not like i said anything bad just stating the facts. If it makes you happy thank you so much Jrichker. Next time something is wrong i will just go along with it.

The information that Jrichker and HISSIN50 have provided to people on this site over the years have helped thousands of people figure out problems and save them a lot of money by doing things right the first time.

They dispense this advise for FREE!!!!!!!!

There is no need to come in here with an attitude and make smart remarks. That won't get you far with help here, or in life. :nono:

Heck, I wish I would have had this resource 20 years ago when I started out with Mustangs. It would have saved me a lot of time and money.

It's because of people like Jrichker and HISSIN50 that I still visit this site. Heck, I haven't had a 5.0 in over 2 1/2 years.

Sorry to be :OT: , but I felt that that response was uncalled for.


Thanks Jrichker and HISSIN50. You guys are the backbone of 5.0 Tech. :flag:
 
The safest way is to use an adequate new power cable (as a reasonable length of 4 gauge cable is for a 130 amp alt) and not reconnect the stock power wires to the 3G.

If the 4 gauge cable blows the fuse or a terminal falls off (etc), then all the current will be trying to make it through the stock wires. You had better hope that the fusible links blow before the harness catches on fire (and considering that the links have not blown in time with 2G alts, that's not a good bet to take).

Reusing the stock charge wires comes down to being an unnecessary risk.

Just a quick question. If you don't use the stock wiring and that fuse blows you won't be charging correct?

I installed mine the exact way as the directions stated from PA Performance. Is this not good?
 
Just a quick question. If you don't use the stock wiring and that fuse blows you won't be charging correct?

I installed mine the exact way as the directions stated from PA Performance. Is this not good?
That would be correct. If the fuse blows then you would NOT be charging. It is there for protection.

If PA tells you to keep the stock wiring hooked up, (I think it does IIRC), then your answer would be yes. That is not good to hook it up that way. You should unhook the stock charge wires and either A) Leave them unhooked and taped off. (Good if you ever want to go back to a 2G). or B) Remove the stock charge wires completly from the harness and throw them away. (This is what I recommend doing as it cleans up the harness and gets rid of the old wires which are usually in poor shape to begin with.)

This link may help you.
http://www.fordfuelinjection.com/?p=75
 
Wired mine in the same way it shows to here and its still not working like it should. Same old problem. Everything was stock and all of a sudden it would pull so much power that the car would shut off. Stock was 65 amp. Put a 80 amp in out of my truck and it did better but would still die with the ac on. So now I have the 3g in and its not shutting the car off but still voltage is dropping every time I turn something on.

Running with nothing I get 14 v. Running with ac on I get 13.5 v. Running with ac, lights on I get 13 v. Then with all that and the subwoofer turned up I get 12.1 v.

I posted this issue in multiple forum sites and all you fuks just kept saying I needed a 3g. Thanks for nothing. My cars been down for over a year with more money sunk. Maybe I am being a little harsh but I tried to express that my issue was not needing a 3g and all I heard was crickets. Next time I will follow my own guy and not the pin heads that wont listen before blurting out the ass.

End OF Rant!
 
Grounds

Revised 26-Feb-2012 to add testing of voltage drops with maximum load on the circuit or connection under test.

Grounds are important to any electrical system, and especially to computer controlled engines. In an automobile, the ground is the return path for power to get back to the alternator and battery.

1.) The main power ground is from engine block to battery: it is the power ground for the starter & alternator.


2.) The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.

Any car that has a 3G or high output current alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects. The 3G has a 130 amp capacity, so you wire the power side with 4 gauge wire. It stands to reason that the ground side handles just as much current, so it needs to be 4 gauge too.

The picture shows the common ground point for the battery , computer, & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.

The battery common ground is a 10 gauge pigtail with the computer ground attached to it.
Picture courtesy timewarped1972
ground.jpg


Correct negative battery ground cable.
56567d1230679358-positive-negative-battery-cable-questions-86-93-mustang-oem-style-ground-cable.gif


3.) The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to its proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness.


4.) All the sensors have a common separate signal ground. This includes the TPS, ACT, EGR, BAP, & VSS sensors.

5.) The O2 sensor heaters have their own ground (HEGO ground) coming from the computer. This is different and separate from the O2 sensor ground. It is an orange wire with a ring terminal on it. It is located in the fuel injector wiring harness and comes out under the throttle body. It gets connected to a manifold or bolt on back of the cylinder head.

6.) The TFI module has 2 grounds: one for the foil shield around the wires and another for the module itself. The TFI module ground terminates inside the computer.

7.) The computer takes the shield ground for the TFI module and runs it from pin 20 to the chassis near the computer.

8.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally.


See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. Be sure to have the maximum load on a circuit when testing voltage drops across connections. As current across a defective or weak connection, increases so does the voltage drop. A circuit or connection may check out good with no load or minimal load, but show up bad under maximum load conditions. .

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Extra grounds are like the reserve parachute for a sky diver. If the main one fails, there is always your reserve.

The best plan is to have all the grounds meet at one central spot and connect together there. That eliminates any voltage drops from grounds connected at different places. A voltage drop between the computer ground and the alternator power ground will effectively reduce the voltage available to the computer by the amount of the drop.