My 3 cylinder, CGPA, 12v engine is struggling to start after it's not been used overnight. It turns over OK but coughs and splutters. On second attempt it starts straight away, as it has always done on the first turn of the key up to recently.

My VAG code reader does not show any fault codes.

I'm wondering if the cause is lack of petrol fuel pressure caused by a failed non return valve.

Is there a a NRV in the fuel system?

Or could there be an auto choke process that isn't working as it should?

TIA

1 hour ago, Doily said:

there a a NRV in the fuel system?

I don't think so.

Does the fuel pump prime when you first open driver's door?

In Mk1 Octavia's fuel tank there was an NRV on the outgoing line of fuel sender, at least in a 1.9TDI110 that I used to own, so Mk2 Fabia could have one too.

Thankyou for your replies.

I didn't know that the pump should run on opening the drivers door.

I shall check at the weekend when I get home.

Update : Breezy_Pete you could be onto something regarding the driver's door.

This morning I got daughter to start car after pausing with only the ignition on for 10 to 15 seconds before turning the key to start.

It started perfectly normally.

Where can I see a circuit diagram for my 2011 Mk2 Fab, so I can check out the door lock and priming functions circuit and wiring?

2 minutes ago, Doily said:

Where can I see a circuit diagram for my 2011 Mk2 Fab, so I can check out the door lock and priming functions...

Does lights left on audible warning work if you go to exit vehicle having left lights on?

I'm thinking that maybe the car isn't aware of door opening; most likely because of a broken wire in door bellows.

Edited 7 hours ago7 hr by Breezy_Pete

Further update: Yes, Breezy_Pete. Just done a test and the lights on audible warning does work.

First hypothesis is toast then.

Here's the relevant circuit of the fuel pump relay - J17- and the so-called fuel supply relay J643 (which should kick in for a couple of seconds when driver's door opens for the first time after at least a half-hour layoff).

Triggered via BCM pin taking the lower coil connection of J643 low.

[173] connects to fuel pump.

[37] is a permanent 12V from fuse 46.

[136] is a feed to the ECU relay.

J643 lives in position 10a in cabin fusebox

Edited 1 hour ago1 hr by Breezy_Pete

Wiring diagram for CGPA mk2s built before May 2011 is subtly different but functionally equivalent, I believe. Do you know when it was built?

I only know from the V5C the date of first registration was June 2011.

Thanks for spending your time on this Breezy_Pete. It is much appreciated

Quite likely it was built before May 2011 then.

Let me know if anything in the above wiring snippet doesn't seem to correlate with what you find, but I doubt it will be an issue.

The main problem you'll face - I think - is that the relay panel on Fabias isn't really intended for easy after-build access.

Edited 54 minutes ago54 min by Breezy_Pete