78 280z Lost Power

[rome03]

Hello everyone,

I'm having trouble getting my 280 to start. I have been driving the car for months without any electrical problems and she starts up every time right away. All of the sudden, from one day to the next it no longer wanted to start. It wouldn't even turn over. I started to get that crazy clicking noise coming from the Ignition Relay. I opened it up and the connections seem fine. 

 

I have a good battery. The posts are clean and wires have a good connection. I have cleaned the fusible links, they're nice and shinny to ensure good contact. I check all of my fuses and they're all good. 

 

The car has no power. Nothing in the car turns on: lights, stereo, wipers, turn signals. I don't understand how the car would loose power like this. The white wire that is connected to the solenoid with the power from the battery also looks good. Is there a main relay or fuse from the car's main power that could have blown? One of the times I tried to start it I heard a small pop-hiss sound. The kind of sound a fuse makes when it goes out. It sounded like it came from the engine bay but I'm not sure. 

 

Need help. This is my daily driver.

[seattlejester]

Any voltage readings to help us out?

 

Battery

Power to starter solenoid

Maint power wire

 

For a sudden stop of this nature I would say probably a dead battery, a main ground falling off (the one near the battery, not neccessarily on the battery) or a fusible link from the battery to the wiring harness going off line.

 

Voltage readings will quickly sort through the problems. And continuity tests will quickly help chase them down.

Edited December 27, 2013 by seattlejester

[Slowpoke]

How do you know the battery is good?

[BluDestiny]

Get some voltage reading from the battery, then check if anything is coming out of the ignition switch.

Edited December 27, 2013 by BluDestiny

[rome03]

I don't have any voltage readings to share, i don't have a voltage reader. I hope to have some today, my friend will let me borrow one. Ill try checking the grounds again. 

 

Battery is good because I took it to auto zone to get checked. It turns on other cars and I even tried another battery from a running car.

 

The ignition feels the same. Lets just say it was bad, why would that affect the power to stereo, lights, blinkers, everything?

 

Also, Sunday night was the last time it ran and what was weird it that it idles perfectly but on Sunday when I turned the lights in it started to idle a bit different. There was a slight change in the revs. It would go up and down up and down, similar to a vacuum leak. You couldn't notice it much and it would only change when I turned the headlights on.

 

So is the crazy clicking from the ignition relay normal?

Edited December 27, 2013 by rome03

[seattlejester]

It would be advisable to invest the 7$ or so for a multimeter, sometimes harborfreight has coupons for free ones with purchase of something. It will be invaluable for diagnosing electrical problems AND solving them. 

 

If the ignition was bad, it would not send power through the ignition circuit which sends signals to power on your distributor and anything else ignition related like the fuel pump, dash lights, anything that needs the ignition circuit to ground to complete the circuit. If the ignition was bad I think the hazards and headlights might work, but the blinkers would not.

 

Clicking from the ignition relay means an intermittent contact. A relay has two circuits, a signal circuit and a power circuit. When the signal circuit is complete the relay "clicks" the power circuit on. If you are hearing it clicking several times it means that it is receiving many signal pulses, either bad from the signal power or the signal ground. Usually when a relay fails, it melts in the on or off position, so it doesn't sounds like it has failed, but sourcing a replacement would not be a bad idea.

 

There should be a voltmeter actually in the car that detect the incoming voltage to the cabin, what is it reading (it is in the cluster of three gauges above the radio)?

 

I'm inclined to believe it has something to do with the main power or ground unless someone has been playing around with the harness in your car. This would be a simple 3 minute task with a multimeter, so please get one.

 

*First check the battery is outputting 12.x volts. Any less then that and the battery is not healthy and needs to be charged

*With the battery connected check the voltage at the starter and alternator. These two are actually connected so they should be reading the same. This is a good time to check that the bolt that holds the ground and power are securely attached.

*Next you will be tracing the power wire into the cabin. Check that it has the same voltage as the battery.

*If at any of these points you are not getting a voltage reading, something is either not tightened or there is a break in the circuit.

[rome03]

Thanks for the tips Seattle

 

I will be purchasing the tool. In the mean time, I started to check the wire that goes from the starter to the the fuseable links. I found that the main wire that is spliced and feeds power to the fuseable links was burnt. I kept peeling it and it was pretty much burnt all the way to the links.

 

I also checked the small wire that connects to the starter and it was ok. The large power wires that are after the fuseable links looked ok. Only the ones before were burnt.

 

Since the wires are part of the piece with the links how can I fix the car if the wires are burnt. Can I bypass them temporarily. ?

[seattlejester]

Was that small black wire cut before hand? Or did you remove the sheathing to take a look at the wire?

 

Small wire to the starter is just a signal wire. It is not supposed to nor does it carry much of a load. It just tells the solenoid when to take full power from the heavier gauge white wire. The power actually flows towards the starter from the fusible links, not from it. If the small black wire was in the condition it is pictured before the metldown, it could have shorted against the power terminal and made the starter run while the engine was running or something similar causing main power wires to fail.

 

Right now you are in the mindset of trying to get your car back and running. You should be in the mindset of finding out what caused the problem in the first place, or else it will happen again, as well as figuring out how far the damage got.

 

So to answer your question, yes you can bypass them temporarily taking full power from the battery/alternator, but the bigger more pressing question is why did the wires burn instead of having the fusible links burn.

 

The white wires from my recollection are the main power wire to the starter. That would definitely explain why none of the accessories work since that circuit burned the main power to the rest of the car isn't making it to the cabin. There really should be no reason for the burn since the exhaust is on the other side, the only thing I can think of is a pretty extensive short circuit, or maybe the starter getting stuck in engagement and burning out or some such situation. Once again even in that situation I feel like the fusible links should have popped.

 

Do you have a good set of crimps and connectors and various gauge wire 10 at the minimum or higher for replacing the starter wires? If not it may not be advisable to start the repair, wait until you can find someone familiar with the repair process with the tools. I would definitely wait before starting until the voltmeter is in hand to check that that is the limit of the problem, if the amperage was high enough ti melth 8-10 gauge wire, it would not be surprising it did not carry on further down the line. Now would be a good time to read up on upgrading the fusible links to some heftier fuses instead of bits of wire and looking into the starter relay mod. There may be a good chance that he fusible links have gone to if they were doing their job.

 

It may be worth your time to disconnect the battery and take out the starter and have that looked at. Unless the white power wires were cut before hand and grounded against the chassis or something of that nature, the starter somehow caused the overload. The carbon brushes on the motor have either died or the retracting mechanism for the gear is malfunctioning or something of that nature.

 

Once again this is all speculation until more pictures and some voltage readings/continuity readings start coming into play.

 

Sorry this is all jumbled, I may come back and edit this a little later if you want to wait.

 

Things to check:

Starter (carbon brushes, retraction mechanism, etc etc, be very careful these put out enough torque to turn the motor over and will behave violently, good to have to inspected at a parts store that is familiar with starters if you have never had to deal with one)

Ignition relay (visually doesn't mean much, the innards are the important part, either visually checked by taking it completely apart, or using a multimeter and a power source)

Fusible links (if they did their job, they should have burned out underneath the plastic shielding, now is a good time to upgrade to some high rated fuses, or a well rated circuit breaker as the fusible links may be hard to find)

Main power wires (white and white with red stripe, these will have to be checked to make sure the burn didn't happen all the way down the power line, for replacement, make sure it is at least the same thickness if not thicker, the white wire especially takes a lot of load during starting)

Edited December 29, 2013 by seattlejester

[rome03]

Seattle,

Thanks for the response. I was the one that peeled the signal wire back to check it. I also checked the power wires that continue after the links into the harness and those are fine. I opened up the ignition relay and it was in good condition and all the connections were in place. Nothing happened to the fuseable links, I checked them. The problem was coming from the main power wire that connects to the starter, the burnt out one in the picture. Once I replaced it with 10 ga wire and connected it to the fuseable links the power came back and the car started and ran like before. 

 

I have noticed that sometimes when I turn the car on, the starer makes a little bit of a grinding sound, like if it got stuck after the car is on. Not sure if this could have caused the problem after months of driving the car. The previous owner replaced the old starter. 

 

You make a great point though, I will be trying to figure out what is causing the overload that would have burnt the wire. I'm just glad I can drive it when I need to. I'll get the voltmeter and start to see if there is some kind of overload.