Surging Idle after 3g Install

[66stangbluework]

Just installed my 3g Alternator and the idle surges, I have not yet installed the 4g ground could this be the problem. Very dissapointed. I have no voltmeter.

 

[Snikt89GT]

Just installed my 3g Alternator and the idle surges, I have not yet installed the 4g ground could this be the problem. Very dissapointed. I have no voltmeter.

I didn't upgrade the ground and i'm not having a problem.

 

[66stangbluework]

now the black/red wire is supposted to be hooked up to the post on the back of the alternator right? along with a 4g wire going from the post to the positive post on the starter solinoid?

 

[Snikt89GT]

now the black/red wire is supposted to be hooked up to the post on the back of the alternator right? along with a 4g wire going from the post to the positive post on the starter solinoid?

That's how I did it (and how most instructions read), but some people on here will tell you that's wrong and just to put the 4G wire on and not the stock ~10G wires.

You really need a voltmeter to check if it's running properly at idle

 

[66stangbluework]

im so worried I fried something *bangs head into wall repeatedly* If I have a new 4gauge wire running from the post on the 3g to the post on the solinoid do i still need the black/red wires

 

[66stangbluework]

also if the serpentine belt was too tight would it do this?

 

[Snikt89GT]

also if the serpentine belt was too tight would it do this?

I highly doubt it, why do you think it's too tight?

 

[jrichker]

im so worried I fried something *bangs head into wall repeatedly* If I have a new 4gauge wire running from the post on the 3g to the post on the solinoid do i still need the black/red wires

The black/orange wires should be left connected at the starter solenoid but not connected to the 3G alternator. That prevents any overload or fire problems when you use a properly fused 4 gauge power feed from the alternator to starter solenoid.

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 best
place for the block ground is where the battery ground for the
starter bolts down. 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 a much current, so it needs to be 4
gauge too.

The chassis ground and battery pigtail ground go to the bolt being
pointed at in the following photo.

Picture courtesy timewarped1972

Once you have fixed your ground problem, see "Help me create the Surging Idle Checklist" at http://forums.stangnet.com/showthread.php?t=534062
for help with your idle problems. The first post contains all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

 

[66stangbluework]

Thanks All. The system was just not used to a good amperage I guess. Everything worked out after it ran for a bit. I thought the belt was too tight because the pully off of the 3g was a little bigger. I was just bieng paranoid. Thanks for the help :SNSign: :SNSign:

 

[66stangbluework]

Thanks All. The system was just not used to a good amperage I guess. Everything worked out after it ran for a bit. I thought the belt was too tight because the pully off of the 3g was a little bigger. I was just bieng paranoid. Thanks for the help :SNSign: :SNSign:

 

[HISSIN50]

Glad you got it. If you had the battery disconnected during the install, it indeed could have been relearning where it needs to be. I've seen a few 5.0's idle-hunt, idle low when cold, etc for a few drives after the KAM is cleared.

Review JR's post to make sure it's all copacetic and that you have the additional power ground pathway and you should be good.

Enjoy!