Fuel pump question

M-j-b

M-j-b

Club Member
Not sure if this is the right place to post this,

So.... 280z wont start,

Have gone through many pin outs and found ignition relay issue.

New fuel pump is on the car, yet is testing as open circuit across the + and -

I am second guessing myself really.

Have put 12v through the positive to ground. And with a bulb inline.

Tests as open circuit and zero operation.
I suppose my only doubt is, does it need fuel inline to have a circuit.. fail safe type switch?

Can anyone can confirm? Thanks
 

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Not sure if this helps but some mentioned in another thread that some oil pressure senders that has 2 blades which is to allow power to the fuel pump.
 
safety cut off is the flap in the AFM so hold open and you can hear the fuel pump running . if so only half the relay may not work but take a good look at the cold starter and thremo stat if the not connected right it wont go test it by downloading the 280z fuel injection bible of google . lots of 280z owners rip all the original stuff out by if you make sure it mega clean and get to grips with how it works ie signel from thremostat to cold starter then to ecu then injectors throught AFM it fine and you can upgrade it also . all the best from a 280z owner .chris ps if you need a fuel pump ignition relay have a look at bosch relays on ebay the one for a 280z was also fitted to other cars from germany so you dont have to get one from the US
 
Last edited:
chris frizzell said:
safety cut off is the flap in the AFM so hold open and you can hear the fuel pump running . if so only half the relay may not work but take a good look at the cold starter and thremo stat if the not connected right it wont go test it by downloading the 280z fuel injection bible of google . lots of 280z owners rip all the original stuff out by if you make sure it mega clean and get to grips with how it works ie signel from thremostat to cold starter then to ecu then injectors throught AFM it fine and you can upgrade it also . all the best from a 280z owner .chris ps if you need a fuel pump ignition relay have a look at bosch relays on ebay the one for a 280z was also fitted to other cars from germany so you dont have to get one from the US
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Thank you for the response,

I had checked for switching voltage at the pump,
I have fitted a new pump.

The fuel rail is now at full pressure. Pump and fuel all fine

Spark is also fine and fires with carb cleaner.

Still not starting, a really odd issue.

1: all earth pins checked on the ECU
2: airflow meter flicking to adjust (operating ok I believe)
3: live feed and negative fuse links testing ok
4: dropping resistor impedance tested at 6ohm
5: injectors removed cleaned and measuring 2.4ohm
6: pin out tests on fuel pump relay test ok
7: pins at injectors are switching negative to flash an LED positive holding and switched negative.

The problem I am having is the earth does not appear strong enough to fire injectors.

Has anyone come across this before?

With a proven fire pulse across the injector plug via an LED, yet will not illuminate a bulb that had been used to fire the injectors whilst cleaning.

Thank you in advance
 
I have been through every test in the EFI fault finding bible.

All tests without fault.
Therefore can only be the ECU.

Currently looking at aftermarket EFI kits.
I am thinking EZ EFI from Z car depot.

Has anyone any experience with other EFI?

Thanks
 
Hi

Have you checked the operation of the EFI relay. It controls the operation of the ECU and injectors. Should be on the kick panel near the ECU according to the EFI manual. If this isn’t energising then the injectors will not fire.

Huw
 
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