Audi a3 - hard start issues

[ak118]

Hey, just have a problem with my audi a3 that cant be diagnosed was wondering if anyone can help?

Car is audi a3 2.0 tdi (184bhp) quattro 63 plate same as a golf gtd engine with about 65k miles.

Issue with starting car intermittently - takes a while to crank, before starting usually happens in morning or when car hasnt been used in a while. Once car has been driven for the day then its fine.

Issue being going on for a couple years but happening more often

Had diagnostic check on obd system no error codes - had new fuel filter.

 

[northpole]

that is a symptom of fuel returning to the tank so you got a leak somewhere in the fuel circuit... probably the fuel filter housing isn't air tight... IMHO if it has been doing it for years, replace the whole fuel filter housing and put in a new fuel filter and before closing it fill it up to the brim... worst case you got a problem with one of the injectors but in most cases it's the fuel filter housing that has isn't airtight. (usually from people overtightening it cracking the housing or the seal isn't sealing right)

 

[Sibmets]

I assume it's not related to battery and starter - that it cranks good and strong - than it could be fuel related - fuel from fuel return line let's fuel sip back to fuel tank and it takes time for the fuel pump to get it back to correct pressure when You turn the key.
I'm not familiar with this engine, but in my B7 v6 TDI I couldn't event start the car because this valve in injector fuel return was faulty and was leaking fuel back to tank and also let the air in the system which clocged the injectors with air.
I suggest checking what's the situation with fuel pressure in Your car.

Sent from my Pixel 6a using Tapatalk

 

[ak118]

Thanks for responses! The battery has been replaced last year with a new one. I do find that when the car has more fuel in tank its easier to start.

 

[northpole]

Aka fuel returning to the tank... there's a leak somewhere period... you could ask a good diesel garage to pressurise the fuel system to find the possible leak.

 

[SJon]

Poor starting is also a symptom of a malfunction in the alternator. Do you see the battery light on the dash ever, once the engine is running?