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SeKcGamer

1976 280z 2+2 running problem

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I parked my z for about a month after rebuilding the engine and driving it to school for about two months. I daily a different car to go to work to save on gas, and when I went to start my car it was dead because I left the radar on. I jump started my car with the daily driven car. But as it charged up enough to start and run, I let it sit for about 15 min. I started to drive it and when the rpms were up and I would let off the gas, the car turns off. I don’t know what the problem would be. (Pictures of rebuild)Image1532991631.815833.thumb.jpg.8a93489f8dac57248c3972ec4845c0f8.jpgImage1532991694.508865.thumb.jpg.72b691800cf924ded705a653d1b3bbfa.jpgIMG_2063.thumb.JPG.a2de35f5191e67830eeefb4b3acb0808.JPG

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Your battery is probably so dead that the alternator can't keep the voltage up at low RPM.  If you went from a stone dead battery to driving the car after getting a jump, that's a n issue.  It puts a heavy load on the alternator also.

We all use jumper cables at will but sometimes they shouldn't be used.  Should have charged the battery up first.  Plus letting a battery go completely dead is bad for it.  They often don't recover.  Check your voltages.

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Your battery is probably so dead that the alternator can't keep the voltage up at low RPM.  If you went from a stone dead battery to driving the car after getting a jump, that's a n issue.  It puts a heavy load on the alternator also.
We all use jumper cables at will but sometimes they shouldn't be used.  Should have charged the battery up first.  Plus letting a battery go completely dead is bad for it.  They often don't recover.  Check your voltages.

Would it also effect the alternator ?


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Some people say that it will just by overloading it.  It has to produce high current for as long as it takes to charge the battery.  And most of today's reman alternators aren't very durable to start.

Your hand held voltmeter will tell the story.  The dash meter too, but it's not as accurate.

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I changed the battery(warranty) and the problem still persists. The car will start normally and if you rev the car more than 3k the engine will Bog and the rpm guage will bounce around and eventually die. At that point it always smells like fuel.


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That sounds very much like mine when the ignition module was dying.  After it did what you describe you could let it sit for a few seconds and it would restart.  It would run fine if you kept it below about 3000 RPM.  But if you revved it, it would do the same thing.  The tach needle action is a big clue.

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That's the California model, for single pickup distributors.  It might work but you'll lose one pickup.

But I've never heard of IGM-4.  It might not be a Nissan part.  Looks like a risky bet.

Their eBay store sells a lot of parts though and their ratings aren't too bad.

https://www.ebay.com/usr/spark-surplus

https://www.ebay.com/itm/NEW-OUT-OF-BOX-OEM-For-1975-76-Datsun-280z-Electronic-Ignition-Module-IGM-04-/182015405068?oid=182824115436

Edited by Zed Head

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I have a CA car (single pickup) got that module off ebay, think it was the same dealer as the price looks like what I paid. Works fine. A swapped it for the OE one (that was working) just to make sure it worked, kept the OE as a spare.

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re that after market spark module, I opened it up just to compare to the OE unit. It had noticeable fewer parts, maybe later module did to. I Opened up both to examine them for use of electrolytic capacitors. Those are a chemical based capacitor well known for having a service life (they dry out). The OE had a couple IIRC the after market had none or maybe one. FYI, the ECU also had few if any electrolytic cap in it as well, that is a good thing. The parts in it were of very high quality.

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That is good to know.  $50 for a new ignition module is a great price.  The two pickup model (seven external terminals) is more expensive though.  One for $100, one for $140.

https://www.ebay.com/sch/m.html?_ssn=spark-surplus&_from=R40&_trksid=m570.l1313&_nkw=280z+module&_sacat=0

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So I put the new one in. The car ran perfect. But the car wouldn’t turn off and in order to turn it off you have too hit this small spot in the ignition and it will slowly die. Woke up this morning drove my car to work and at first the car turned off using my method, but the CPU light on my volt gauge was coming on and wouldn’t turn off. Now my battery is dead


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7 minutes ago, SeKcGamer said:

So I put the new one in. The car ran perfect. But the car wouldn’t turn off and in order to turn it off you have too hit this small spot in the ignition and it will slowly die. Woke up this morning drove my car to work and at first the car turned off using my method, but the CPU light on my volt gauge was coming on and wouldn’t turn off. Now my battery is dead

Which one?

Sounds like a possible voltage regulator or alternator problem, or ignition switch.

You need to give more details about the car and any modifications you've made to it.  You have some weird stuff going on.  And the stock Nissan volt gauge doesn't have a "CPU light" so it's not clear what you're talking about there.

Plus, if the car wouldn't turn off how do you know the battery is dead?  It's still running, right?  Details...

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Well I’ve already changed the voltage regulator and I’ve already put a new alternator when I rebuilt it. On my middle pod in the center I have (volts/fuel) I believe and at the very top corner it says “CPU” and right next to it there’s a lil bulb that turns red when something’s wrong it looks like. When I try to turn the key to off the car stays on but if you move it to the left like a “cm” there’s a point in it where the car starts to slowly turns off. And if I don’t do that the car will remain on. Even in off position. You just have to hit the right spot, I’ve never had this happen so I don’t know if it is the ignition switch 🤷🏿‍♂️.

 

 

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Is it the stock Nissan gauge?  There is no "CPU" on Nissan stock.  Mine says CHG.  If the light is on it means that there's a problem with the charging system.  "New" doesn't mean good.  Check those new parts.  You might have a short that is "backfeeding" the ignition system.

 

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Could it have something to do with the ICM?, since two of the wires in the new one dont actually connect to anything on the ICM. I believe it’s the brown and white wire.


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On 7/30/2018 at 4:02 PM, SeKcGamer said:

when I went to start my car it was dead because I left the radar on.

Did you turn the radar off?

Did you leave the brown or white wire touching any ground points?

Take the ignition switch apart and see if it works correctly without the key.  You can work the electrical switch with a screwdriver when it's apart.

Charge up the battery then disconnect the things that might be draining your battery.

You have too many weird problems to pick just one cause.  The engine starts but won't shut off, the battery dies when sitting, the charge light is on when the engine is running.  That could be three separate causes for three problems.  Start troubleshooting with a fully charged battery.

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Okay, let me help better understand this. The engine indeed doesn’t turn off when you try to turn it off. The charge light is only on when the car is off not when it’s running. And no the battery doesn’t die when sitting, the battery dies because the “charge light” won’t come off when the car is completely turned off. They are currently no things connected to the battery in order to drain it. And I left the white wire connected to one of the empty terminals on the ICM that it should of been on, but the ICM itself doesn’t have a wire on that terminal, so it’s basically screwed into an empty terminal. But the brown wire is just there not connected to anything, it’s loose because it doesn’t have a spot.

 

 

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Sounds like a bad voltage regulator, or something is connected to the Charge light circuit that should not be.  The external regulator controls the Charge light.  Charge up the battery, see if the Charge light is on, then unplug the voltage regulator.  If the light goes off you probably have a regulator problem.  If it stays on you have a short somewhere.  

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