Hello!

Now I have run out of ideas and hope someone here on the forum can help me find my error.

Nissan 300ZX Z32 1991 TT

In summary:
The fuel pump is not running.
fuel pump relay does not click, (It's brand new so it works)
But not receiving a signal from THE ECU, Black / purple.
If I Bypass the relay, it turns on instantly. (12v + the orange wire in the relay)


Long version:
The problem is:
Fuel pump does not start when I turn the key, either in the ON position or when I try to start.

As it should be:
It will turn on for 3 seconds to build fuel pressure. Then it will have a constant signal
This does not work



I have tested the following
* Checked the ECU for error codes and everything looks good, code 55 = no fault codes found.
* Checked fuel pump fuse next to the battery
* Switched fuel pump
* Have replaced the fuel pump relay at the feet (Green)
* In the relay, there is 4pcs cables, 2x white / black that has constant 12v +, 1pc orange 0 volts, 1st black / purple that goes to the ECU. (Signal cable)
It's the signal cable that receives a ground signal from the ECU to the relay that allows it to click. This does not happen
Have tried to ground the wire right at the ECU, relay clicks and works as it should and the pump runs at full speed. This then means that the ECU is not sending the signal to the relay.

* Have checked the eccs / ignition relays click when turning the key, and they do.
* Have removed the CAS and checked so it works. means that THE ECU should get the start signal (I've also checked through ECUtalk and the shows start signal 1.
* Have tried to ground the FPCM (Fuel Pump control) directly to the ground via the white wire, but will be no difference at all. This means that the problem is before this?

The cable that is orange occurs in several places.
It is also up to the air regulator at iacv unit.
If I put 12 volts on the orange cable the fuelpump start at full power.
No matter where I put it, if I do it at the pump, in the engine compartment at the air regulator or at the relay.
Isnt the orange wire supposed to constantly have a 12+ signal from the ECU as soon as the key is turned? As i understand that wire also controls the air regulator?


Here is the circuit diagram if you get any smarter by it
http://z32.wikispaces.com/file/view/ECCS_colored_m.gif


Hope someone has some idea regarding this phenomenon, would be appreciated enormously!


Kinds regards

 

"Long version: The problem is: Fuel pump does not start when I turn the key, either in the ON position or when I try to start."

Had the same prob in my '86na. Came out of nowhere. We ran a temporary cheat direct from fuse block to fuel pump until we figured it all out. It was the ECU. Replaced it with a salvaged unit, removed the short cut, prob disappeared. But that's an '86