Fuel Pump / Relay - Diagnostics help!

[24Ozed]

Hi Guys,

I’ve just purchased a 260z 2 seater which is fitted with an L28E (2.8 EFI)

Its not running because of a fuel pump issue, which I assumed was a faulty fuel pump.

After hooking up another fuel pump there is still no joy.

 

I’ve checked for power using a test light but there is no power on the positive lead to the pump in the “key on” position.

To my knowledge .. to trace this further up the loom the next check point would be the fuel pump relay ?

 

If so … where would this normally be located ? (near ecu, near ignition, somewhere else?)

And then how do I test that the relay is working?

 

Any help would be appreciated.

Travis

 

[Scoota G]

Assuming it's all standard equipment there's a solenoid right next to the fuel pump. Try testing the solenoid.

[luvemfast]

Make sure the fuel pump is for EFI, I have been caught out on this before.

EFI needs about 36psi compared to carby 7psi (approx).

Since your car has an L28E fitted, there may not be any particular place for the relay as it could be installed aftermarket.

 

How long since its been running? Is there fuel getting to the fuel rail?

[24Ozed]

Will have a look to see if there is a solenoid anywhere near tonight when i get home from work.

 

Its definately an EFI fuel pump, it looks to be a 280zx original unit.

Apparently car was running 6mths ago (according to previous owner)

There is definately no fuel getting to rail at the moment.

[Zedman240®]

Whoever wired up the car, did they use the original wiring or did they make their own? On the zeds, they have a large green wire running to the rear for the electric pump; check if that wire has been used or something else. That green wire goes from the rear where the tank is to behind the heater control panel. I've used that wire many times when I've fitted EFI to my last 2 zeds.

[RB30X]

Another thing to keep in mind is when you first turn the ignition on, your fuel pump relay will only be getting power for a few seconds. After that it's the ecu's job to continue the signal to the relay according to oil pressure (once the engine is running). For the purpose of fault diagnosing, and once you find the relay you could run a new signal wire to the relay with 12v to keep it on regardless of key position. Be careful though.

[24Ozed]

Thanks guys..

Correct me if i'm wrong... but..

So to the relay... there should be 4 pins;

 

12v from battery

Earth

Signal (is this from ecu?)

Output to fuel pump

 

It does look to be standard wiring.

I do know the green wire you are talking about zedman.. Its possible it may be the one going to the fuel pump already (but its getting no power to it)

[dazzed]

fuel pump relay is hanging or mounted near the battery and is brown in colour

[DatPilot]

There is also a pump kill switch in the Air Flow Meter. Make sure the contacts are clean and not corroded.

 

the switch is designed to stop the pump if the engine stalls (afm shuts) or in a car crash.

 

 

Good pickup point for a security device too....

[24Ozed]

Thanks for your help everyone !

All fixed now..

 

Turned out to be a combination of a faulty fuel pump...

And a very well hidden kill switch that the seller forgot to tell me about !

 

Car now runs smooth as

 

Thanks again.