1998 Prado 3.5 5VZ wont start.

[negneg]

So my Cruiser wouldn't start, i though it was fuel shortage as it sounded that there was no fuel. so flicked the switch from after market LR fuel tank. Tried about a minute later and it started. Drove home and when i tried the next morning it would not start, despite there now being half a tank pumped over from LR tank.
Sound like no fuel is getting through. i checked fuel flow and it was slow. There is power to the fuel sender unit, that is working, so i thought there was power to the pump and i thought it was a tired pump. So i dropped the tank, the ONLY way to get to the fuel pump... and decided to apply power directly to pump! pump operated. i Supplied power to the pump and the vehicle started and idled just fine!

i then checked the power at the plug and there is NO power.... but there IS power at the sender unit. both wires cables are in the same harness... its just power to the pump that has been "cut"

My vehicle does not have an Immobilizer, (i dont think) as the central locking and alarm cut into the main wires but the unit box is not between the line. like normal immobilizers do.

i have check ALL fuses... and as mentioned vehicle starts when external power is applied to pump. So now i am suspecting-

The fuel pump relay... (where on these vehicle does this relay hide?)

Fuel Variable Resistor...

Transponder key system (key amplifier, computer assembly, Transponder coil) does the Transponder cut the spark- because it started when the fuel pump had power.

What cuts power to the fuel pump in these EFI systems? i have also bridged the Diagnosis block and there is NO codes flashing. unless i'm doing this incorrectly.??


Has anyone ever had this issue? and what would it most likely be of the above mentioned items. (it could be the alarm as there might just be an immobilizer in there)

Any links to the factory Manuals? ;ve searched but cant find any links for the OE manual.



Please, any one with info i would be really grateful.

 

[ftw76]

did you have any luck finding the relay

 

[negneg]

Hi Guys,
Sorry for late replay- i have narrowed it down to two issues- either the ECU or the Key transponder- Both are expensive to fix here in SA. i traced the wires and traced it to the Open relay on the right of the dash (right hand drive) i then added a gadget there that send a pulse up the wire and traced it to the ECU- So that is not sending power to the relay to close and connect the power to the pump from the ignition. i bridged this relay socket and it works perfectly. so iether the ECU is faulty or the Transponder is not telling the ECU to send power to the open relay.

what do you guys think? is this how the key transponder works?

 

[FloridaFJ80]

I would rule out the transponder before you get an ECU? Or do you have someone that can let you borrow their ECU so you can test? Let us know what you have ruled out.

 

[Pedders Suspension]

Can you get a scanner to plug in and pull the error codes?

If there's an error, there's usually a code stored in either the Engine ECU or Immobiliser ECU as a result.

Even if you borrow one from a friend or drive to a local independent garage, you'll have more of an idea as to which component it might be.

Have you tried your spare key?

Regards

Michael @ Pedders

 

[negneg]

Im VERY worried about borrowing an ECU, just now my vehicle is the issue and it blows that ECU. my pants will be full!!!!
What sends a signal to the ECU to send power to the close/open relay to send power to the fuel pump. because if i can figure out that, im pretty sure we'll find the culprit. i say this because there is just NO power coming from the ECU to the open reply. so what ever is stopping that, be it a short in the ECU or is there an EFI relay that gets power form the ignition then goes to ECU then to open relay then to pump? or does the ECU get power straight from ignition and THEN it send power to the various areas??

its a ball ache!!