Audi A5 1.8TFSI - Fuel pump not priming when drivers door opens

mickdw

I've got a long cranking on a couple of occasions now when starting my car. Once started it's fine.
I've been keeping an ear on the in tank pump when I open drivers door and this evening, no prime and long cranking so the lack of priming is the issue.
I will check tomorrow whether the car recognises the door opening as a start point.
Anyone know of a common issue with pump itself or door lock or door wiring etc?

DanielGibbons

mickdw wrote: »

I've got a long cranking on a couple of occasions now when starting my car. Once started it's fine.
I've been keeping an ear on the in tank pump when I open drivers door and this evening, no prime and long cranking so the lack of priming is the issue.
I will check tomorrow whether the car recognises the door opening as a start point.
Anyone know of a common issue with pump itself or door lock or door wiring etc?

I have a Mk4 GTI, it's a 1.8T but a different type of engine.

The pump would prime under 2 seperate conditions:
1) The drivers door opening
2) The ignition being switched on

I was having a similar issue, changing the relay seemed to work.

My door open switch was dodgy, so I knew that on the key was the only way the car would know to prime it.
However, on occasion, turning the key wouldn't prime the pump.

Try turning to ignition (with radio and fan off) and listen out for the pump.

That could be totally different for your car, but that's how I diagnosed mine.

mickdw

Thanks, will have a look for relay and see if it can be swapped.
Will keep an eye out for when it doesn't prime and see if I can rule anything in or out.

Ubbquittious

So basically if you get into your A5 Dukes of Hazard style there's a good chance it won't start?

mickdw

Ya, I believe they call it the 'Rednek Halten Funktion'

Lucifer

From memory of working on another Volkswagen with similar issues, they sometimes have 2 relays, 1 for prime and another for running. Had me confused at first as wire colours were the same from the wiring diagram.

Eireann81

I had a similar issue before on an A4 tdi - long cranking every time. If I switched the lights on first, it would fire up instantly.

mickdw

I've heard of that one on the tdi before. I think it was George Dalton mentioned it.