Hesitation after warm engine

[Zed Head]

What's the big blue cube?  Dinosaur alarm system?

You could follow the wires from the alternator T plug back in to the harness.  They should go to the regulator or to some splices where it used to be.  And the internally regulated alternators have an "S" and an "L" molded in to the case by the T plug.

[240260280z]

10 hours ago, Zed Head said:

What's the big blue cube?  Dinosaur alarm system?

You could follow the wires from the alternator T plug back in to the harness.  They should go to the regulator or to some splices where it used to be.  And the internally regulated alternators have an "S" and an "L" molded in to the case by the T plug.

Rubik's Cube Holder... NISMO option in the 80's.

[siteunseen]

I thought it was an intercom from Sonic. 

[Palmettobug]

So I believe this is the regulator you were referring to.....

 

 

And this is a picture of the alternator....

I see an E on it. Don't see the S or L you talk about. Not sure if this is a 40 or 60 amp.

[SteveJ]

Well, you have a voltage regulator, and the alternator has stock plugs connected to it. It's probably a stock sized alternator.

[Palmettobug]

Dang it. Well, there's another mod I need.

[Patcon]

The stock alternator will work fine unless there is some good reason to need more current. The internally regulated alternator is a little easier to source, especially if traveling

[Zed Head]

On 9/20/2016 at 4:23 PM, Palmettobug said:

That was going to be a question of mine a little further down the line. How do I tell by looking if someone swapped the alternator?

Thought everything was synched right in the driveway. Tried to pick the kid up from school and the car died under accelerator load. Spent 30 minutes screwing with the carb adjusts to get enough power to make home. Stopped by Advanced Auto. Guy says he turned the front 1 and a 1/2 turns before it affected the rpm's, the rear one he turned 3/4 of a turn before affect on rpms. He said the front carb needs to go in for rebuild so you might as well do both.

Sound plausible?

I'd offer - don't get distracted "fixing" things that don't have anything to do with your problem(s).  Your dying problem here seems like a large clue of some kind.  If it started and ran well enough to get out of the driveway then died when you gave it some throttle, it should have started and ran again.  The odds of some guy at Advance Auto actually knowing something about 1973 240Z carburetors seems astronomical.  I'd guess that he just turned the big obvious knobs until something happened and tried to sound knowledgeable.  I could be wrong.

There's an N on your alternator indicating externally regulated.  One more clue that it's stock.  There's a 50 and 60 amp option according to the FSM.  Your ammeter should tell you if things are okay.  The fact that the battery has enough juice to start the car since you've had indicate that it's probably fine.

Overall though, seems like you need a new friend.  Who knows old Z cars.

[SteveJ]

40 minutes ago, Palmettobug said:

Dang it. Well, there's another mod I need.

Read up on it first. One of the things you'll need to do is see how the electric fuel pump is powered. If it is the Nissan modification, the power for the coil comes from between the voltage regulator and the alternator. People with a 1973 240Z experienced the battery draining on their cars because the coil stayed energized all of the time. I had that problem until I removed that part of the harness.

[Palmettobug]

I could use new friends that lived closer. You guys are on the coast and I'm stuck here in the middle. Haven't seen anyone from Tulsa on here.

Anyway, last couple of days I have sync the carbs with airflow. I think I got the fuel mixture right. I have the idle dialed in at 1000 rpm in park, 1200 rpm in drive. I make it out the driveway and step on the gas ..... I get jerking and hesitation. The carbs backfire, and the rpms drop to 500 and stall out. I recrank and put the choke on. I can make it around the neighborhood. Haven't been adventurous enough to jump on the highway.

Think I may contact a different shop this time.

The alternator thing I was saying because the headlights run dim. Most of the threads I've read say I should upgrade to the 60 amp and purchase the headlight harness from Dave. I also need the Honda upgrade swap for the windshield wiper motor and the heater blower motor. All of which can wait until after I deal with the carb issue.

[Patcon]

If you're running SU's try shooting something (starting fluid??? guys??) around the throttle shafts to see if they're leaking badly. If they leak badly, tuning can be difficult. If pulling the choke helps your set up is too lean...

[siteunseen]

I agree with Patcon, backfiring through the carbs is a sign of leaning out.  It could be something loose on the balance tube or the carburetors?

http://www.popularmechanics.com/cars/how-to/a3094/how-to-find-a-vacuum-leak/