I've had a thread previously on here about start up issues with my fab diesel vrs, the car was randomly cutting out while driving and then coming too with a jolt in gear change, I changed the cam sensor and that solved that, the issue now is a a dip in revs on start up. I've changed the glow plugs with no change, the car will start first time when the engine is stone cold but once the engine is warm the car will take a turn or two to start then the revs will dip and come back to life, I've just changed the temp coolant sensor as that was what it sounded like but now after warming the engine (sat in the drive) it does the same dip when it's warm. I'm hoping after taking the car for a drive the new sensor will almost "settle in" but what option would I look at next??

Start up- could it be the fuel valve sticking SHUT. Take off the shiny cover( mine says TDI, JUST PULL .& LIFT ),and halfway along the large pipe is a shiny CIRCLE  bit of aluminium. That's the EGR ,and behind that the fuel shut off valve. Which can & does stick SHUT OFF,due to gunge inside. Separate the pipe. , clean out the gunge and see that the valve opens, when the ignition is on .

If this is the case, i would recommend while your at it removing the exhaust manifold and thoroughly clean it.

 

The other thing could be injectors, this is worth a try: 

- there are loads of other videos btw

 

 - have you scanned for faults? 

Start up- could it be the fuel valve sticking SHUT. Take off the shiny cover( mine says TDI, JUST PULL .& LIFT ),and halfway along the large pipe is a shiny CIRCLE  bit of aluminium. That's the EGR ,and behind that the fuel shut off valve. Which can & does stick SHUT OFF,due to gunge inside. Separate the pipe. , clean out the gunge and see that the valve opens, when the ignition is on .

Do you mean the anti-shudder valve? In where the red arrow is pointing, on the shaft that the black arrow is pointing at?

 

That's an air cut-off, not fuel? 

Think I'm going to have to get in the local garage, hopefully will throw up a code and get this sorted, the cars faultless otherwise! Cheers

laptop and a cable (£5) you can save £80 for a diagnostic are plenty of topics about VCDS (free diagnostic software for Vag) you can then post up the results to people here, most of us us vcds. A garage might be able to scan for a code, but a snap on scanner or similar may not give much details. 

If this is the case, i would recommend while your at it removing the exhaust manifold and thoroughly clean it.

 

The other thing could be injectors, this is worth a try: https://www.youtube.com/watch?v=iq_ZGh1KEec - there are loads of other videos btw

 

 - have you scanned for faults?

I think you mean Inlet manifold

I think you mean Inlet manifold

ye that would help :P

Total novice to that sort of thing, there's software i download on the laptop then connect to the car via usb?

http://www.ebay.co.uk/ulk/itm/291544070698

Something like this?

http://www.ebay.co.uk/ulk/itm/291544070698

Something like this?

yes this is the lead i use. + vcds lite http://www.ross-tech.com/vcds-lite/download/index.php

 

coms port show here : http://www.briskoda.net/forums/topic/186052-wheres-the-socket-in-fabia-to-plug-a-vag-com-into/

Edited 4 January, 201610 yr by FromTheDarkness

...Or an ELM327 and an app on your favourite Apple or Android smartphone.... (Though they only do the generic stuff, not the VAG specific extras).

Bought the suggested lead off eBay, hopefully will be here soon then can get a code, started up spot on this morning after it's been sat cold all night!

Is there any chance out of curiosity that the new camshaft sensor I fitted to stop the cutting out could of created the judder issue on start up? Don't think the there was ever the dip issue on start up before I fitted that, it always struggled to start and then lost power but they were both solved. Now I'm left still with the issue in this thread. Still waiting on the lead to plug the car in