Problems starting...still.

[Northernstar002]

https://drive.google.com/open?id=0B0...jNvWll1dWhkTU0Afternoon all,

I have a 2007 A6, 2.0tdi Avant C6 with a bre engine and an intermittent staring fault.

It's really annoying as the car will drive well most of the time but once every 50 starts (roughly) the engine will just turn over and time out. At this point it will bleat about the parking brake, directing you to drive to the nearest workshop. When you turn the key again it will start fine, but the ESP light will be on and cruise control will not activate.

When you get to where you're going and leave it for an hour or so, it will start fine first time. The lights will be out and it's as if nothing ever happened.

That's the most common issue, but once in a while it will refuse to start at all. Just before Christmas this happened. I tried starting it again and again until I gave up and left it - each time it was bleating about the parking brake or sometimes an ESP fault. I brought my other car in the next day and parked behind my Audi - so it had been left overnight. It would normally start after having left it for this long, but it still wouldnt have it. The battery was still at 100%, but just before I called the RAC out I though I'd just try jumping it from my other car. Bugger me the darned thing started!

So, just after Christmas I bought another battery, slightly higher spec than the one that was on there (which was rated at 750 CCA, the new one is 900) and it started straight up following the swap - it continued to start first time every time for weeks until this morning. I was sat in the car park after having switched it off for 20 mins and it would restart. Before leaving it for too long I asked someone for a jump which started it - albeit on the second turn.

I'm going to have the fault codes read asap but what could the cause be?

Why is it so intermittent? Surely something is either faulty or it's not?

I have no confidence in the car anymore.

Help, thoughts or suggestions gladly welcomed.

[niall campbell]

it seems an electrical problem

can you run the car for say 20 minutes, pop the bonnet and feel the + jump start terminal under the bonnet and see if its war, it may in fact be roasting so take care here, it almost started a fire in my car !!

The starter also has to turn the car over at 250 rpm or 280 rpm or the fuel will not go into the engine, resulting in not starting

If I was you, I would get a multi meter and see how many volts you have at car when its cold, hopefully 12.6 volts at battery or roughly

Then I would test at the jump start terminal, should be around the same, maybe POINT something lower but still 12 volts

Then start car , test volts at alternator, should be 14 .5 roughly and then battery, again 14. point something

If its not 14 at battery, then the jump start terminal maybe causing a resistance and not allowing full flow of electricity to run from front to rear of car, this may mean your battery cannot start the car



Failing that its a trip to a VW/ Audi Indy or dealer to see what speed the starter is turning the car over at, if its say 280 rpm then perhaps look at glow plugs

[Northernstar002]

Niall,

Many thanks for your great reply! Very full and informative. Agree that it's likely to be electrical. I'll be able to see how hot the under bonnet jumper terminals get after the ride home tonight - approx 20 mins. The starter motor sounds like its running at the same speed, regardless of whether it starts or not - cant tell a difference but it's worth checking later on down the line.

How would i test the voltage at the alternator? It might become apparent if I'm standing over the engine bay, but I'm not aware of how easy that would be from the top of my head, but I have a multimeter and I'll report back later on.

Kind regards,

Northernstar.

[niall campbell]

you need to push the probe into the connection which is a bit tricky, or cut the coating over the wire to peel back the cover, then retape


When I looked at my wiring in the engine bay, the alternator and starter wiring is in the same loom, winds its way up the back of the air filter, through the jump start terminal into the scuttle/ plenum chamber and into a black box which holds a big electrical connection

The wiring is thoroughly bolted on and was very clean in mine, so a bad earth is unlikely; but could still affect things

At the moment this is the cheapest option, but report back with findings


With the cold air coming in, a frosty morning will put extra load on your battery & starter for starting, so bear this in mind for being a red herring

[Northernstar002]

Cheers,

The battery is only a few weeks old and is a higher output than the previous one (which never sounded as though it was struggling - but I replaced it after the jump start from another car worked a treat).

I'll let you know.

[niall campbell]

One important step in your video though !!!!!!!!!!!!!!!!!!!!


A thing I have noticed is starting in my car is


Put Key IN and turn ignition ON

WAIT UNTIL GLOW PLUG LIGHT GOES OUT BEFORE TURNING KEY

IF YOU DONT DO THIS THEN TURN IGNITION OFF THEN RESTART PROCEDURE


If I don't wait until glow plug goes out, then car refuses to turn over the engine, its just dead.


So try and wait for the glow plug to go out, hot or cold ................................. it is good practice anyway all year round to wait for the glow plug light to go out as this extends the glow plug life & the you should actually wait arounds 2 seconds after the glow plugs are actually still heating up

I think by waiting for glow plugs to go out, it gives the car time to check all it systems


TRY IT & SEE

[Northernstar002]

Ok, noted, but in all the time that I've had the car I've never had to wait for the glow plugs to go through their cycle. I thought I heard somewhere that it's not really cold enough to make a difference.

But, having said that, it costs me nothing to amend my starting procedure and wait for the glow plug light to extinguish before starting.

I'll give it a try and keep you informed.

Many thanks for your continued support and interest.

[niall campbell]

no problem

I only noticed this a few months ago, I don't know why or how it started; maybe I was continually in too much a rush

When I jump in, I now switch ignition on & then put my seatbelt on to kill time !

[wayney]

Hi, I had an unusual starting problem shortly after having cam belt done.
Every so often I'd try to start the car and immediately cut out, slowly it became more regular, thought it was battery dying so replaced, still the same. After 6 months of putting up with it took back to the garage and was told it was something to do with the retard of the timing, so adjusted and never been a problem since.
Just have a spare battery know.

[wayney]

Just another observation, on my 2.0 tdie 2010, when starting I just get in, put the key in and turn and release, if glow plugs are needed the car will not turnover till glowplug heating is complete.
So it seems on mine the car decides if glowplug preheating is needed automatically.