Fuel pump wires and no live.

FrazUK

Member
Location
Dorset
At ignition stage II, I get 0v over the white wire with red trace and 13.1v over the blue wire.

Fuel pump does not prime or run. Any ideas why the red/white shows 0v?

Or how I can rectify this problem. Awaiting parts for battery relocation and fuel pump rewire as per the picture floating about but I don't think it will help as the red/white will still be on 0v.
 
Jump the fp in the diagnostic box.
Then check the front fuse box for the fuel pump relay also the fuel pump regulator under the brake booster for voltage
 
Jump the fp in the diagnostic box.
Then check the front fuse box for the fuel pump relay also the fuel pump regulator under the brake booster for voltage
Will give it a try. Everything I've tried has power just nothing seems to make it out the engine bay to the pump.
 
Right I have no idea why this power isn't making it to the back. I've got to assume it's the immobilser in the car.

So I'm about to do the pump rewire as pictured this will bypass everything in the engine bay. For Pin 86 on the relay can I use any ignition switched live or does it have to be this red/white wire for whatever reason.

I've read where the red wire in the fuse box pictured below is a switched live. [Not my pictire]. Can I run a fused wire down the car straight to pin 86 from this point?

Or is there an ignition live in the boot anywhere?

Failing all that I'm going to run it off the battery with a fused switch which isn't ideal but I need this working.

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your best bet is to find and fix the issue rather than adding wires. The factory system uses a resistor for low pump speed and then a relay for high pump speed that is ECU controlled.

If you have an immobiliser then that is more than likely the problem. my friend had a no start issue on his second FD and i traced that down to being the immobiliser where its relay connection was just push fit spade terminals and one had come loose (Wired into the starter solenoid).
Your immobiliser could be wired into that Red/White Fuel pump feed that runs down the passanger side

If it was me i would remove the passanger side sill cover and pull back the carpet a bit and follow the wire back from the seat to the ECU Area.
You might find that its chopped and intercepted.

you have already checked all the other components now assuming its not a dead Fuel pump.
 
Fair point mate will try and find it, if it is just chopped in to is it just a case of taking it out and rejoining the wire? Pump is brand new.
 
Yes mate just connect back together and hopefully problem solved.
obviously at this point the Immobiliser will be bypassed.

It worth taking a look at the immobiliser its self as it could just be a loose connection.

Good luck! :)
 
Will do mate. Also with regards to this fuel pump resistor I've just put an Apexi Power FC in. Will that not negate the need for it when it learns the idle? Or does it not work like that? This is my first FD so not all clued up on it but I am reading lots.
 
The resister just reduces the voltage to the pump under certain circumstances e.g. idle, low load etc. This reduces the fuel pressure, extends the pumps life and keeps the pump noise down. It's a good feature and why I wouldn't rewire a pump in a way like the diagram above.
 
The Power FC will still control the high and low speed fuel relay, you could delete the resistor or not it doesn't matter both ways.

with it Deleted the base map would idle richer but i assume your going to get it mapped so wouldn't matter.

if you have done the fuel pump direct feed you mentioned in your earlier post then the relay wont be making a difference to the pump speed.