meats75z

Hello to all, I have a 1975 280z that has issues shutting down for no reason between 2-8 min time. Let me start by saying that i had an issue with my fuel gauge fuse blowing as soon as i turned on the ignition, I traced it back to the voltage regulator contacts being fused together going right to ground. Bought a new regulator and the fuse holds. Then i starting having the problem of the car shutting off at different times only with the fuse installed. Traced that problem to the water temp relay. Sensor and relay seems fine when tested. I believe the problem might be in the ignition module which is connected to the water relay via white wire. when the fuse is in, it sends 12 volts through the relay to the ignition module. Could the module be bad or is there another step before that one?

Thanks for the tip Fastwoman. One other thing that i have come across is the dropping resistor. I sorts understand the function so could that cause havoc?

No, I'm an electrician so the electrical troubleshooting was easy. It's the mechanical end that's driving me crazy. Besides it was the fuel fuse on the fuse compartment inside the car that was blowing (10 amp). the pins on the regulator were fused together going right to ground so it was blowing fuse instantly. If you have a schematic it's the third one down on left, or green wire. According to the drawing it goes to the regulator, tach, water relay, and possibly sending unit. Which is also why I'm thinking it might be the water temp sensor. My question is would that cause the car to shut off or just run rich or lean.

Fuel pump shows pressure intil the car shuts down. One other thing i have noticed is that the fusible links under the cover, The smaller one has been replaced with standard wire and also they jump between the white with red stripe to the white on both links. I know it shouldn't be that way but other that the car shuting off at that moment with the fuse in it, it runs fine

Fuel pump shows pressure intil the car shuts down. the fuse is a 10amp which is what it shows. One other thing i have noticed is that the fusible links under the cover, The smaller one has been replaced with standard wire and also the jump between the white with red stripe to the white on both links. I know it shouldn't be that way but other that the car shuting off at that moment with the fuse in it, it runs fine

Thanks to all who responded. still have the problem but will wait till warmer weather arrives.

Thanks for your input. Does anyone know where to find a fsm that won't cost as much as the car?

Thanks for the link, it is very detailed. I think the previous owner did something on ECM by adding resistors on the 5 and 13 pin that go to the water temp switch. Any idea why anyone would have done that? Also any idea where to find a new ECM if i need one?

I have recently bought my 75 280z with fuel injection and it had a short on the fuel fuse. I determined through trial and error that it was my voltage regulator that went bad, bought a new one and solved the problem. Ever since then when the car starts to warm up it will shut off instantly. When the car cools down then i'm able to start it again. Another way to start it and keep it running is to pull the fuse again. Must be temperature related but not sure where to start. Any input on this problem would sure be appreciated. Thanks meats

Hi all, I'm having a problem with my 75 shutting down after it warms up a little for no apparent reason. I've changed the voltage regulator because it was shorting out the fuel gauge fuse. now that i have fixed that problem the car seems to run a bit then cut out. If i take the fuse out it stays on, once installed it cuts out after about 2 min or instantly depending on warmth. I have installed a new fuel filter thinking it might be a bit clogged, but still doing it. Any ideas???????