Hey all,

My '79 280zx (n/a) is cutting out after about 10 minutes of driving. I can turn it back on while rolling and it starts back up every time. (I have to wait until I hear a relay click before I can do this). One in every 10 times it cuts out it revives itself at about 100rpms and jumps back to normal.

So what's the best way to narrow down whether this is a fuel delivery problem or some kind of electrical short? I can't reproduce the issue by letting it idle. It seems like it 'could' be heat related as the car runs fine for the first 5-10 mins every time. My engine temp. sensor is broken but I don't have any steam or oil/coolant loss.

Any ideas appreciated,
Thanks.

 

Id check your fuel pump relay Thats what tt sounds like to me, make sure theres not corrosion or rust on it and it if keeps it up may as well replace it I think their like $20

 

I replaced nearly all the stock wiring from the ECU and the problem seemed to stop for a day. Now it's back again. I'm going to junk the relay and wire the pump up to a switch for a few days to see what happens. Thanks for the reply -- I'll probably be posting again after this doesn't fix it.

 

Found the problem -- partially burnt wire from battery going through the firewall. Unfortunately I must have disconnected/shorted something else while fixing it.

What are the 2 black relay-looking things next to the fuel pump relay? I have 12V going into them through a thick white wire. No voltage is coming out. I can start the car by jumping the 12V thick white/black wire coming out of the 2 black boxes (relays?) to the battery. -- any ideas?

Edit: wrong colors
Edit2: For clarification, the white/black wire I'm jumping to the battery doesn't currently have 12V but it should if the relays were working.

 

Uh I "think" their fuel injections relays but Im not entirely sure. How many pins are on it?

 

They are attached side by side and have 4 wires going in to each (one is a ground wire between the two). The connector that leads to them is a single 6 pin connector.

Thanks for the reply.

 

Ya it could either be your EFI relay, or I think, an inhibitor relay both of which would keep your Z from running