why won't it stay on?

[meats75z]

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

[webdawg1]

Following link should get you going in the right direction...as far as troubleshooting goes...download EFI bible and print it out...Also get hold of the FSM (Factory Service Manual) for your model year, as the EFI bible makes reference to certain sections in the FSM when troubleshooting...

http://www.pape.ws/allan_and_rosanne/Z-Car_Stuff/EFI/280zfuelinjectionbook.pdf

webdawg1

[meats75z]

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?

[abruzzi]

When I first got my 280 the coolant temp sensor was bad, and made the car stumble and run very rich. Jumping between the contacts temporarily made it run correctly. Maybe that's what the PO was trying to do.

Geof

[meats75z]

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

[Pomorza]

www.xenons30.com is where you get it for free. Download and place somewhere. Print off the pages you need and tada.

Jan

[meats75z]

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

[meats75z]

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

[FastWoman]

Meats, you can buy a FSM used on Amazon pretty cheaply. The going price is about $80, as I recall, but I got mine for $24 in fairly marked up condition. (As long as the info is in it, I don't care whether it's pretty.) You can also find FSMs on Ebay. If you're old-fashioned like me, you'll appreciate having the book to lay out where you're working. Of course it's not as compact or as cheap as a download version!

As I recall, the fusible links do jump between white (which is from the battery) and white/red (which runs to the various systems). Of course having ordinary wire in place of a fusible link is not a good thing.

I'm wondering whether your fuel pump is going bad and fails when it gets hot. You might try testing it by running it without the engine running and seeing whether it keeps running. Try jumpering from the battery directly to the + post of the fuel pump (which won't risk overcurrent damage to any of the wiring in the car), and see what it does.

[webdawg1]

Looks like he was trying to trick the ECU into thinking the engine was already up to operating temperture. (I.E. - Bad water temperture sensor)...see page 14-15 in the EFI bible...so in other words...car was probably running rich...added the resistor (pins 5-13 on ECU) to lean the fuel mixture out I'm kind of thinking...probably running really lean all the time now more than likely...

webdawg1

[IdahoKidd]

Hey meats, I am having a hard time making the connection between the fuel pump fuse blowing and fixing it by replacing the voltage regulator. I'm betting changing the regulator didn't do a thing, but that you replaced the fues with one for higher amperage (intentionally or unintentionally). It sounds like you have just move the symptom to somewhere else but have the same problem. Did the car ever work correctly since you have owned it? When you pull the fuse to keep it running, what fuse are you pulling?

[meats75z]

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.