A930Rocket

The car was dieing on me and I'm only getting about 11 volts at the battery, so I swap out alternators yesterday. Not my first time, but I had forgotten what a pain in the *** it was. Why can I drop the engine faster?

Anyway, I figure I'm good to go and take her for a spin. Get a mile from the house and it starts to sputter, then slowly die on me. She starts right back up and I bring her home.

Just to make sure everyone knows I'm having a problem, it starts to do a few small backfires, then a big one. Everyone looks at me like I'm the village idiot. Well, I felt like one.

I checked the fuel pump relays and they were cool, as was the fuse. Maybe swap out my MSD for the stock box to eliminate that. Next I'll check voltage at the battery (its new), then start looking at grounds and follow the pos lug off the alternator to see where it goes and check voltage off that. Anybody know where it goes to?

I hate electrical problems...

DonE

I feel your pain.

The big red wire from the ALT goes to the starter, then to the battery.

senna21

Does the alternator have a voltage regulator inside it or is the VR separate? I used to have a 240Z and the VR was separate. Swapped out the alternator only to have the same problem, and a fried new alternator.

g935cab

if you havent already try the lee rice fuel pump rewire and the yellow relay in the engine compartment our suspect for back fires , good luck ~G

A930Rocket

Thanks Don.

Senna, The later car use an internal VR. I think they switched over in the early 80's.

g935cab, I've done the Lee Rice trick and have removed the "the moon must align with Mars" stuff in back by grounding the fuel pump relays up front to an impact switch. I'll check it, but the switch rarely goes bad.

kens911

My alternator did exactly what you described when it died. I was actually on my way home from vertex with a new alternator. I made it half way home then had to get it towed. That was last year right after I got it running.

A930Rocket

Funny you mention that. I don't think I've ever done engine major work with out the alternator dieing within months. If I had the money I would have sprung for a new one, but I got a rebuilt one from Vertex.

slownrusty

I'm with you Rocket...I could not believe how long it took me to change my alterntator last summer. I kept saying man I could pull the motor in the same time...LOL

Good luck!
Yasin

A930Rocket

UPDATE

I jacked the car up just now and took a look at the starter leads. The nut had backed off slightly and the leads were slightly loose. Cleaned them up as well as the trans to body ground. Replaced all nuts with new jamb nuts. One hour max time working. I now I have 13.8 volts at the battery and cut off switch. Need to take it for a spin, but I'm sure I've fixed it...

Moral of the story: Check your wiring first before you spend the money and time!

kens911

Speaking of that I have mine running now but no tach signal

A930Rocket

Did it happen after you replaced the alternator? Have you checked the wiring at the CDI box? At the tach? Can you jump a wire from the CDI output to the tach and see if it works?

kens911

no it happened when I put the engine back in yesterday. I think something isnt hooked up It was dark when I was connecting everything. I took it fo a test drive about 10 pm. 2 am I woke up and realized i hadnt torqued the lug nuts, So I got up and got the torque wrench out and put it by the front door So wouldnt drive off to work in it.

DonE

I would add just a bit more to your moral: look for the simplest solution first. Congrats on finding the problem. I like success stories....

A930Rocket

I did that one time 20 years ago on a Mustang. After some work on it, I drove the car for a test spin in the neighborhood and kept hearing a thunking noise. Drove it back home, checked the lug nuts and I had forgotten to tighten one, much less get the lug nuts threaded all the way on there.

Now I go around the car twice with the torque wrench to be sure.

A930Rocket

Thanks Don. The worst part is I put off doing this for months due to time and money. Could have it fixed and driving it a long time ago.