MK5 Golf 1.9 TDI with same old hot start problem!

[VWVIX]

Hi All,

Firstly, sorry about the length of my post... I have a bit of a timeline.

My first post and it's the same old hot start problem! I've read endless threads on different forums about this and it's driving me mad! What's happening with my car doesn't seem straightforward to me.

I bought the car December 2015 (with the hot start problem) – when the car was up to temperature it would crank over for about 3 or 4 seconds and then eventually start.

Cold start was no problem.

Camshaft Sensor replaced – November 2016 (made no difference).

Over the last 6 months or so the cold start has varied a little, but will generally start fine.

In May, things changed – when up to temperature it would crank over for about 2 or 3 seconds and then it would sound like it’s dying and stop cranking completely. Then I’d turn the key off, wait a few seconds, try again, and it starts. But not as quick as it does when cold.

There had been quite a few times between May and September when I had tried it a second time and again it sounded like it was dying, and then on the third go it would start.

Took it to a local garage in June but they couldn't figure out what the problem was as I don't think they'd had much experience of the hot start problem.

On reading some forums, I thought perhaps it might need a new battery. Before changing the battery, and with the car fully up to temperature, they connected a jump start battery pack to my battery and this extra power started the car straight away. They then disconnected the battery pack and the car went back to cranking again for about 3-4 seconds before starting. We tried this a few times. So, thinking it may need a new battery, I bought a more powerful Varta battery - this was in June.

On about 5 or 6 different occasions throughout July/August, when the engine was cold, it would crank for a few seconds and then sound like it’s dying, as mentioned above. So it wasn't only doing this when hot.

Then in September things changed again! It went back to starting after cranking for about 3 or 4 seconds... it no longer sounds like it's dying!!

I'm completely confused... where it's been intermittent, could this be a problem with the battery/starter motor connections?

Is this completely obvious that I need a new starter motor? - I keep thinking that I've put the starter motor under so much pressure for nearly 2 years that it's had enough!

I'm in a position at the moment where I'm trying to decide which direction to go in...

- Do I go to a garage and ask them to clean my battery/starter connections to see if this makes a difference.
- Do I buy a new starter motor.
or having read on the forums about the hot start remap... do I pay £200 and get this done in the hope that it works?

Any thoughts or advice would be so greatly appreciated. I really don't know what to try first!

Thank you so much for your time

[Crasher]

We do replace a lot of starter motors because of poor cranking speeds, it must hit 280rpm for a clean start.

[VWVIX]

Hi, thanks for coming back to me.

Do you think the random problem with my starter motor going from cranking well to then sounding like it's dying and then coming back to cranking well again, sounds like it definitely needs changing?

Also, you mention the 280rpm that it needs to reach for a clean start... am I right in saying the hot start remap is basically a quick fix rather than sorting out the actual problem - the starter motor.

Thanks for your time.

[Crasher]

Yes the remap gets around the fueling hole below 280rpm.

[VWVIX]

So would you say the intermittent problem that I've had with the starter motor cranking over well and then for a couple of months sounding like it's dying, then returning to cranking well again, means that it definitely needs replacing?
Thanks

[Crasher]

The only way to tell is to carry out an engine run immobilised, starter motor cranking speed test.