Hi everyone.

Got some issues with mother in law´s Audi A4 1,8 -97.
It just died while she was driving, now it cranks but won´t start.
I wont get any fuel up to injectors. The fuel pump and pump relay is replaced, I can bridge the relay to get the pump flowing but it wont start anyway.
Tried to swap ECU but did no good, tried to disconnect coolant sensor but no luck there either.

When I disconnect the throttlebody the engine starts to promise but wont start.
So I replaced the throttle body but of course it wouldn´t start.

Got no fault codes in ECU... What the hell am I missing??

 

Have you replaced the fuel fitler as I believe there is a lowside pressure regulator built in, be aware it has to be installed in a specific postion if it has the pressure regulator inside of it. I would check the crank sensor as they go out often on the B5, but you usually will get a fault. Let me know what you find..

 

HI thanks for reply

Both crank and cam sensor have been replaced, I have´nt replaced the fuelfilter since I get fuel up to the rail if I bridge the relay, do I need to replace it anyway you think?

 

No if you can get fuel up to the rail then it's not the filter.. Let me think on it and respond later today... That's an odd one..

 

Thanks

I think it´s a real simple problem in the end, but I just can see it, I get spark.
But the fuelpump wont start when I crank, but there´s no problem with realy or ignition power to the relay,
If i got it right the earth to realy come´s from ECU, is the ECU using earth as signal to fuel pump relay?

 

On Audi ground is always the control switch with power being constant and the ECM switches ground to turn components on

 

What would make the ECM not to turn on fuel pump?