GreenMachine

First of all i am going to apologize if this is covered somewhere else I will gladly take a link to that thread if it is already covered.

Second I have to say thank you for all of you I have been lurking this forum for the last year (since I have gotten my Zx) and it has answered many of my questions but now I have one I am stumped on.

History:
1979 280zx N/A
I am the second driver of the car and Bought it with 97,xxx miles on it now has around 130,xxx on it
Only modifications I have done are a after market stereo and A cold air intake.
The last 2 month while the car was in idle all of my dash lights (break, Key in ignition) and the other red ones would all come on. Giving the car gas and getting to city speeds about 25 mph would shut them all off and the car would run fine.
Around the time that started I started having a starting issue, Crank the car it would run for about a minute with no oil pressure on the gage then stall. Crank it again and the oil gage will pop to operation pressure and it will run.

My Current Problem:
3 days ago I was driving home from work on a highway after being on the interstate going all above about 55 mph and the car just shuts off on me. Dropping the Clutch did not turn it over it just engine breaks the car.
Turning the ignition over would not start it.

That night i got it towed over to my apartment complex and didn't worry about it until the next morning.

The next day due to having a low battery voltage and the previous light issues (See History) I went to my local auto parts store and purchased a new alternator and installed it. Cranked the car and it ran at idle for a while so I went to take it for a test drive. Turn out of my apartment complex give it gas on the highway and it shuts off I pop the clutch and coast it into a near by business. and that is where it has sat the last 2 days because I can not figure it out.

What I have done:
Checked the Resistance from the Pos. side of the alt. all the way up to the battery term with none on my electric meter

Checked the Resistance from the S spade on the Voltage reg. to the positive battery cable with none also

Tried a newer ignition coil on the car and it had the same issue (tried this due to having oil around the old one.

Checked Voltage of battery good at 12.4-12.8 V
Running alt runs at 14.5V I think?? (in my apartment doing this from memory) one time when i brought the RPM's up to about 3K i saw a spike in the output of the Alt. but I have not been able to duplicate that.

Possibilities:
I am thinking it may be my ignition control unit or the distributor?
I seem to remember reading in another post that they have a Safety mode when something is going wrong with the charging system to stop anything from breaking.

If anyone has any Ideas or can point me towards a post with a similar issue I would be Greatful for any help.

The Young and Un-Seasoned mechanic
(as seen in another post)

GreenMachine

Also, After it shuts off I can not start it again. The starter turns the motor over but it will not run. I have to wait for about 10 minutes and then I can crank it to have it run for a short while before it dies again. Today I got it to run for about 30 sec and then stall again right after it started.

NismoPick

Welcome to ZDriver!

Let's begin at the "no start" problem as that may play a role in the other.

An engine needs 3 things to start (if mechanically sound):

1. Proper Air
2. Proper Fuel
3. Proper Spark

So when your car won't restart, does it have spark at all cylinders? Does it have fuel pressure? Can you hear the fuel pump kick on?

GreenMachine

Sorry for responding so late work had an emergency and had to call me in. I know that the fuel pump is working because the lines stay pressurized I pulled one of them off to check that a couple of days ago. I have not checked to make sure that the Distributor cap is getting spark yet. I will do that when I get off tonight. I have been considering the IC as a failure point.

FricFrac

I'd check for spark first...

koprutzxt

JUST MY EXPERIENCE: ALL FINDINGS BASED ON MY TRIAL AND ERROR
i have had this happen to me: car ran well then sometimes acted funny, shut off while driving sometimes comes on sometimes not.usually dies only after use guess a bad IC shows its symptoms when it gets warm i suppose
and it turned out to be the ignition control muduale, it pretty much tells the car when to turn on(ie its in park for auto matic) and tells it to stay on (the key is in on position) it controls it by allowing spark to the distrubiter.. when i got a new one i took the other one apart and for the most part it was nothing but corrosion dust...

and the whole light thing happen to me once, it turned out to be my negetive cable. if u replace it dont forget to ground it twice. since my -cable was no good the battery held a charge but would not power the car so if i stop reving it would die since it was only powerd by the alternator.

believe me an i have had some seriouse issues becouse charging system and im a better person for it now, but there is no fail safe for bad charging system it will run on ur battery till it dies.

" its my personal belief that the zx has weak amp out put alternators
i replaced mine with a first gen z31 (84')alternator (bolt on) plus new fem wire ends the harness clip does not match, o'rielys honored my warranty and exchanged my 280zx one for a z31 on the reason that it put out too little amps and my z felt like it woke up powers my electric fan adn subs..."
ur volts sound perfect at 14.5 max charge volts sometimes i get spikes when i install a new alternator it passes

rogerz

battery, battery cables, alternator are most likely the heart of your problem. you say you had red lights until you hit 25 points to badalternator. kop??? has it right except nothing wrong with zxt alternator you need a good battry and cables to get the voltage to make the electronics function. the ground cable should go down a foot to a bolt below the battery box an then to th starter. trying to ground thru the starter is not a reliable connection.

GreenMachine

OK so an update as of tonight.

I took NismoPicks advice and others to check the spark. Went out to the car cranked it it ran beautifully. I got to move it up some so It was not on such an incline. Then the car died.

I didn't have an assistant so I just pulled the plug out of the distributor cap and tried to turn it over. No pop or spark that I could see. So i pulled the cable off to see if it was a bad cable (I have Nice NGK cables but the one to the ignition coil seamed really loose) still no pop). I did all of the tests possible on the Ignition coil from the Haynes manual without an assistant it seemed to check out fine. Even replaced with a previously known good ignition coil and it still was not sparking.

One time I got the coil to run and put the volt meter on the positive and negative sides of it only getting around 1.3 Volts? is that right seems low to me. if it is a bad connection could I just try a ground to the body from the Ignition coil?

there is what looks like a small capacitor mounted on the ignition coil bracket that was grounded to the Distributor that snapped off so I re grounded it to the bracket. why does that go through a capacitor if it has no power?

GreenMachine

Fixed my issue I swapped out the distributor with the one from my 81 and it fired up and ran without any issues. May have been from not hearing my baby but she seems to run even better than before