Cold Start issues - glow plug flashing - steps taken but issue still persists.

[mamaalik]

Novice at posting so excuse any mistakes, have searched but my issue seems to be somewhat unique.

audi a4 b8 2.0 TDI - caga engine - 143bhp
diagnostic symptoms -

problem started only in the cold weather
only if left over night and temp drops to about 7 C or less

2 patterns that occur

when key inserted and clutch depressed the engine / starter cranks and then shuts off. - the glow plug light flashes almost indefinitely once the starting process fails.
this can happen several times - max was about 20 and the eventually it will start.
sometimes the glow plug remains solid and then a light comes on saying switch engine off and check oil.



have run vcds version 12 many times and other than some long standing AC faults and engine speed sensor fault no new issues, nothing in particular to do with fuel pump, relays, or glow plugs.

steps tried.

glow plugs changed, and checked with multimeter seems to be fine
the glow plug relays changed - doesn't seem to make difference, - i have even removed the relay and the engine would still start (after the several attempts as mentioned)

i have changed fuel filter recently also.

despite no mass airflow errors, i have also cleaned this with appropriate cleaner.

I had the AA come out and they checked the voltage going to the plugs once the temp was low and the engine was key was pushed, he suggested that the glow plugs were not receiving any voltage. - im not so sure about this. my multi meter doesn't seem to reach deep enough for me to check voltage my self.


i did get the alternator changed recently (problem was hapening before this) and the only thing left for me is to filute the coolant appropraotely, the mechanic just put in g13 coolant without diluting it, he said to top it up with water but i will drain and use a tester to get it at the right level, i dont think this would cause cold start issues.

i wonder if anyone could spot a pattern to these symptoms and offer advice.
Have spent much time learning and trying to be self sufficient. any thoughts on what I could do further (was thinking about changing fuel pump but that seems a costly trial and error).

I have taken a video of the process that i will upload shortly.

thanks in advance

[mamaalik]

audi a4 b8 cold start problem - YouTube

audi a4 b8 cold start issues part 2 - YouTube

[derbyracer]

Have you recently had the emissions fix carried out on this car? Could there be a link between the two?

[niall campbell]

firstly, always allow the glow plug light to go out before attempting to start the car .......................... this allows car to get the heat the glow plugs up, and this will prolong the life of the glow plugs also


So switch on the ignition of the car, put your seatbelt on ............................................ this will allow the glowplugs to heat up & light go out

Then start the car !!




Also the glow plugs for around 1 to 2 seconds after the glow plug light goes out, are still heating up.

All year round you have to wait for the glow plug light to go out


My A 6 2006 & others have the same problems, we wait and car starts fine. Try it and see

[paddyb123]

In your op it shows a engine speed sensor fault which can also be called crank position sensor this is where i think your problem lies and they dont always log a fault