1978 280Z Dies at operating temp

A forum for owners of S30 and S130 Datsun Z's... 240Z, 260Z, 280Z and 280ZX!
jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

1978 280Z Dies at operating temp

Postby jeepers92 » Sun Dec 16, 2018 7:40 pm

I've read around 50 posts and still not finding what I need.
I bought a 78 280Z 2.8L
After fixing several issues got it running well. When i get out and drive it and it's at operating temp, it will just die. No spit sputter or anything else. Just Die.
The fuel gauge goes to empty.
What i've noticed is that their is no sound of the fuel pump coming on at all at this point. I try to start it and their is no fuel getting to the engine, if you just turn on the key their is no sound from the pump.
After waiting about 20 to 30 min and the car has cooled you can turn the key, the pump comes on and you can hear it, and the car will start.
Let it idle awhile til it's warm again, it dies.
Try to start again, no sound from the pump.
I know that sounds like the pump is bad, but i wonder if it could be anything else and what i might check before spending the money on a new pump.


FrenchPople
Posts: 68
Joined: Thu Jan 22, 2015 9:34 pm
Car: 1983 Datsun 280ZXT 2+2
2016 Nissan Frontier Crew Cab Desert Runner 2WD

Re: 1978 280Z Dies at operating temp

Postby FrenchPople » Sun Dec 16, 2018 7:57 pm

I'm not sure if you have messed with the distributor or not but it sounds like you might have a crank angle sensor starting to take a dump on you. Start the car and run it till it stops. After that remove one of your ignition wires and check for spark. It there isn't spark for a while then it most likely is the crank angle sensor in the distributor. Not sure how easy it is to change on the S30 but the S130 Turbo is a slight pain without removing the distributor. Hope this helps

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Sun Dec 16, 2018 9:34 pm

I started it and ran it til it died. Checked as you suggested and their was spark.
Something else I noted while doing this.
if i turn the key off an on several times after several attempts of turning it on and off (not starting it) i will eventually hear the pump kick in.
I thought it may be the pump. I noticed that the volts were going down on the dash display as the car ran until it died. I didn't notice it before, it just noticed now. I imagine that suggests a parasitic drain somewhere.
Where does one start testing for a parasitic drain. The starter is new, the alternator is new, the water pump is new, spark plugs and wires are new.
I did not replace the distributor and I need to buy a timing light for the timing to double check it, i don't have much for working on older cars.
Any advice on this front? I'll check again tomorrow after charging the battery if the battery drain happens and perhaps that's whats killing the car.
Thank you for your suggestions.

FrenchPople
Posts: 68
Joined: Thu Jan 22, 2015 9:34 pm
Car: 1983 Datsun 280ZXT 2+2
2016 Nissan Frontier Crew Cab Desert Runner 2WD

Re: 1978 280Z Dies at operating temp

Postby FrenchPople » Sun Dec 16, 2018 9:55 pm

IDK if a parasitic drain is what's happening right off. If that was the case you would not be able to start the car after it cooled down without a charger. The next two things I would do is check all grounds and check the connection at the ecm for any corrosion. I had corrosion on the pins on my 83 and it caused it to not go under it's own power. I had another 83 that would only go so far because of it. And if those are ok I would check both the main/ecm relay and the fuel pump relay. That's the best advice I can give. Also don't do what I did and try not to buy as much parts as possible. I did that before finding out all I had to do was clean the connections at the ecm and to say the least I wasn't a happy camper.

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Thu Dec 27, 2018 6:40 pm

After a lot of checking on different things, I'm leaning to the toward the Air Flow Meter. The connections seem fine, the fuel pump seems fine. I did some continuity tests on the air flow meter and it appears to not have anything at all when i check the ones listed for the pump. Does this sound reasonable? What I don't understand is why it works for awhile then stops, is that something that the air flow meter really does?

FrenchPople
Posts: 68
Joined: Thu Jan 22, 2015 9:34 pm
Car: 1983 Datsun 280ZXT 2+2
2016 Nissan Frontier Crew Cab Desert Runner 2WD

Re: 1978 280Z Dies at operating temp

Postby FrenchPople » Fri Dec 28, 2018 7:19 pm

Unfortunately no that is not something the air flow meter would do and you don't want to change one when it's not bad. I know from experience on that one. Now I did just talk to a good friend of mine in New Jersey that I bought my Z from and he suggested that the ignition switch may be the problem. With his suggestion get a wiring diagram and start the car and run it till it dies. After that jump the necessary wires at the switch to see if that works. If it does then that is your problem. Also if you have not changed it and don't know the history then it should probably be changed anyway. Thankfully the ignition switch is a inexpensive part to buy at the local parts store. Somewhat easy to change as well. Let me know what you find out.

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Sat Jan 05, 2019 8:02 pm

Hey French, so tested and replaced the whole ignition switch etc still have the same issue.
I'm thinking now that i'm just spending a lot of money.
My thought is, what if i bypass the fuel pump relay's.
Can't i just run a line from hot to pump and negative with a switch in the middle?
Here's what i'm thinking. It has to be a wire somewhere i can't find, or something in the pump or relay that happens when it heats up.
What i'm thinking is Run it til it shuts off. Hook up a bypass switch and flip it, see if the fuel pump comes on. If it does, it's probably not the pump but something in the relay area or wire along the way. Either way, While i'm driving it which i need to do soon, so my dad can have his truck back, I can be looking for and replacing the line up to the relay and the relay area itself.
Trick is, what would be the best way to run the bypass and how would I do it. I have a toggle switch ready.

FrenchPople
Posts: 68
Joined: Thu Jan 22, 2015 9:34 pm
Car: 1983 Datsun 280ZXT 2+2
2016 Nissan Frontier Crew Cab Desert Runner 2WD

Re: 1978 280Z Dies at operating temp

Postby FrenchPople » Sun Jan 06, 2019 7:46 pm

Unfortunately I am out of ideas. I am hoping that someone else on here might see this and may have an idea of sorts. As for by passing the pump might work I'm not sure if it can be done. I think the zx trubo was the only 280 that had the variable voltage pump. If you have a service manual hopefully that will be able to.give you the info for the wiring and then some. And if you were in Jersey I'd say go see.my good friend tto help get that z back on the road. (If you do live out that way pm me and I'll see if he will be able to help you out.

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Mon Jan 14, 2019 11:09 am

So, I bought the relays and they are not the same pin design as the ones in the car and I have to rewire them. Does anyone know how to do this. I've attached doc of what I bought and what it looks like as cross overs but, I can't make sense of it, never did do electronics.
One is a 4 pin, the other is a 5 pin. Can anyone give me some help with this?
https://www.docdroid.net/4M0eepL/fuel-relays.pdf

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Sun Jan 20, 2019 2:51 pm

UPDATE: Still need help.
Went through a lot trying to figure this out and I have this posted on another forum, maybe someone here can give me a hand.

Here is a full picture of the problem and what we've tried that hasn't worked.

The original problem is that the car would run for awhile until it reached operating temperature, maybe a little longer. At that point it would die.
There would be no electricity in the car. dash wouldn't work at all. jumping battery does nothing. No lights come on.
The battery is in great shape, brand new and the voltage is where it is supposed to be.
When you turn the key on and off without trying to start it, the fuel pump would not come on.
Once you let it cool off, then when you turn it on, the fuel pump would come on and you could start the car.
In short you can drive it only for a few minutes at a time.
We posted on forums to get some info and we tried several things, we checked the obvious stuff first like wires and grounds.
Then we checked the air flow sensor, It seems to check out in continuity nothing sticking.
We checked for a parasitic draw. Didn't find anything.
Everything we kept checking seemed ok.
We would run the car til it died, then check the individual pieces.
We ended unchanging the starter and the alternator because they are original very old. Those work and check out fine.
We tested the wiring harness with no issues I thought.
*Did some continuity tests according to the FLM for the wiring harness oddly it doesn't match exactly so I can't honestly tell which ones to check. For instance the FLM shows a plug at 20 but there isn't one in the harness in place 20.* Everything I checked did have continuity*
We then ended up pulling those two fuel relays out and testing them and they didn't show any results following the guides that we had and then posted the info original and we were told it was bad.
That's where we were told to buy the new relays. Then we got caught up on the wiring.
I'm just not convinced that the relays are really bad. I actually took them apart to look at them honestly because I was trying to understand the wiring. I don't know anything about it, I'm a visual person so I usually can reverse engineer things.
*I replaced the relays and in doing so one of the fusible links burned out because the 5pin I bought was not a 2 solenoid relay. I got another one.* (they are not plugged in when I do the test with direct wiring for the pump) Tried both ways.
The other thing we did was check the fuel pump. We ran the car til it died, then put direct hot and ground wires to it to make sure it would turn back on, and it did.
I bypassed the fuel relays, directly ran the fuel pump from the battery to a switch so I can manually turn it on and off, wanted to make sure that the pump wasn't bad though continuity came up fine. After the car dies I can flip the switch and the fuel pump comes on, but no power to the dash.*
I forgot to mention that we did also change the ignition switch.
I also put on a clear fuel filter so I can see the gas is going through.
Any info you give is great. The car is a daily driver however, it's my sons. He is using my truck while his car is at my house. Since I work from home I don't need the truck daily, however off work, I can't use it either because it's at his house.
So now we are back to square one.
I would love this to start running for my son so I can get my truck back.
Thanks for any info you can provide.

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Sun Jan 20, 2019 3:55 pm

*MORE INFO*

Once it dies if you have the key on accessories the headlights will stay on, the defogger will stay on, the hazards will work and the fan will work for the heater, as well as the electric antennae .
The oil gauge, fuel gauge, volts gauge do not work.
The batter starts out at 11.31v.
when I turn the pump on with the switch, drops to 11.10.
if you crank the car with the pump off drops to 9.6
if you crank the car with the pump on battery goes down to 9.5
Never noticed but when you turn the key to the accessories there is a click behind the glove box, I assume that is normal. I checked all fuses in the kick panel too to make sure they work and are the appropriate sizes.

jeepers92
Posts: 9
Joined: Sun Dec 16, 2018 7:36 pm
Car: 1978 280Z 2.8L

Re: 1978 280Z Dies at operating temp

Postby jeepers92 » Sun Jan 20, 2019 3:56 pm

*More Info*

I thought at first it died at operating temp, but, in paying more attention, that's not exactly the case, it will run maybe 20 min past operating temp.


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