Ok so when the car is full of fuel she starts and drives normally but as the fuel drops to below 3/4 it struggles to start when cold (2/3 key turns while revving) but starts fine when its warm when the fuel drops below 1/4 it lost power greatly.

I have had the injectors off to replace missing clips and change the o rings since doing this the trouble started have i not done something correctly here or would it be something else.

Ive gone over what i done to double check and researched online and these symptons point to failing fuel pump is there a way i can chack this

Below is the injector have been told that these are not standard by previous owner the fuel rail was raised by using two nuts each side causing a surge in revs so i looked online and got some 6mm spacers this solved the surge (air getting in i think )

Injector

Has the engine been mapped to use those Audi RS2 345cc injectors? They are bigger than standard vRS but smaller than BAM injectors. I'd be tempted to stick some standard injectors back in to at least eliminate that issue. Is the fuel pressure regulator standard?

Fuel pressure regulater is standard as far as i know it has been mapped (prev owner claim) no paper work to back up tho is it worth going to a mapper

Ok had the car in the garage and he worked out that the fuel pump is not turning on first time for some reason i tried this morning turnin ignition on and off until i could hear the pump start (3 times until it did) then turned the key to start and started first time thinking of checking the relays iver the weekend to save me time looking where are they located please will also stick a volt meter on pump connections to try find the cause

It could be the immobiliser; do you have 2 proper keys or only one?

It has a aftermarket one fitted he did mention that could be the cause but would have to look into it further to be sure

I can't see why anyone would fit an aftermarket immo (alarm maybe, immo no) since the standard one is a transponder unit and will stop the car cranking/firing unless it recognises the key.

 

So if there are no fault codes, I'd strongly suspect the aftermarket immo, particularly if it was fitted with bodgeScotchloks.

Could be the fuel pick-up pipe in the tank has a split in it.

 

Imagine drinking through a straw with a split in it; its fine when the split is submerged, but once the liquid has dropped enough you start sucking bubbles as well.

 

This would also give the pump a hard time as it's not meant to suck air.

Yea but wouldnt i still be able to hear the pump trying to suck fuel up i have to wait until i hear the pump before starting i will check the relays tomorrow as its the easier thing to do than rip out the immob lol

Yea but wouldnt i still be able to hear the pump trying to suck fuel up i have to wait until i hear the pump before starting i will check the relays tomorrow as its the easier thing to do than rip out the immob lol

But if the pump continually gets bubbles through it, it'll probably start to fail and stick, hence why sometimes you can hear it and sometimes not!

After testing the relay i looks to be the immobil affecting the pump