HDi Starting issues

[FuST]

Ok, so here goes my story (i'll try to keep it short)

Last year in the cold I noticed my trusty HDi wouldn't start quite as fast as it does in the summer. No concern there, I know batteries lose some of their capacitance when it's cold.
This year, however, things started to get worse. The last couple of days it took about 8-10 seconds of starting to get the engine running.
Strange thing is, last Friday it started up just fine, even though it was a lot colder than Thursday.

So today I did some fault-finding. Tested the battery: it measures about 9.8 volts during starting and comes back up to 12 when I let go of the key. Not ideal, but not that bad either.
Tested all glow plugs (pain in the **** to remove btw) and found the one on cylinder 2 faulty, so I replaced it.
Used PP2000 to check for any faults, none came up.
My HDi has the "ticking injector" problem, so I listened to all injectors with a stethoscope and found the No. 2 injector making a lot of noise compared to the others.
Made a screen-cap video of me driving around for a bit while monitoring injector corrections: https://youtu.be/jNYK0n-xzg8 (PP2000 is in Dutch, sorry about that) and I don't really see any inexplicable values.

So fast-forward 3 hours, I try to start the engine to go to the supermarket. After about 10 seconds of cranking, still nothing. Turn off the ignotion and immediatly try to start again and it fires right up after about 2-3 cranks. Can't remember if I heard the lift pump though.

So, what could this be?
I'm considering bad battery causing the ECU to miss some fuel pressure values or maybe a bad lift pump or connection to it. The car runs and drives fine though.

Any advice on the situation is very much appreciated.

[madmadmax]

so a battrey should not drop below 12v when starting so all the computers can boot up propley and the starter motor can run at full power, your probelm is mostley the battrey. i would not worey about the injectors as long as it runs and dose not smoke

[Piggy]

Yeah. Battery.

Next for me would be starter dying and pulling all that power... But battery first. Esp if it's 3yrs old or mors

[FuST]

Ok, I'm with you guys on the battery going bad, I know computers can do some weird stuff when underpowered.
The battery is at least 3.5 years old, it was the one fitted when I bought the car.

What this doesn't explain to me is why it seems to be an intermittent problem. One day it would have trouble starting while the next it fires up no problem. Same time, almost the same outside temperature.

Anyhow, will replace the battery and see if that solves it.

Thanks for the replies!

[Mighty306]

Might be worth doing some of the tests described here too. http://www.aa1car.com/library/voltage_drop_testing.htm

[Uberderv]

The ECU will prevent starting if the engine isn't rotating fast enough. A dodgy battery could cause this, < 12v is not good not just for the starter but also for glow PLUG operation.

[Magenta Sunset]

Yeah. Battery.

Next for me would be starter dying and pulling all that power... But battery first. Esp if it's 3yrs old or mors

i'd agree with battery.
I find anything less than 10.5/11 volts is going to be troublesome.


   

[Poodle]

As you say, the intermittent nature of the problem doesn't point to the battery. Especially if the engine starts after 8-10 seconds of cranking; a weak battery would no longer be able to start the car at that point.

That said I'm not sure what else to suggest. It's not an immobiliser issue since the car starts eventually if you continue cranking over. Fuel pressure seems likely, although without other symptoms (noisy pumps, running on after ignition is switched off, hesitating/cutting out under high load, consistently requiring extended cranking to start, etc) I'd be looking at the control system rather than mechanical components. Perhaps have a check of the fuel (brown) relay and the wiring to the plug, see if there are signs of arcing around the pins or any damaged wires. Could also be a failing cam or crank sensor.

[FuST]

@Mighty306: I'll do some of the tests described there, but I'm thinking battery for sure now (read on )
@Poodle: I'll check to see if I can find any problems with the relay, cam and crank sensor seem to be OK (PP2000 is reporting Ok sync on them).

So yesterday and this morning the car was even harder to start than last week, requiring about 5-8 seconds of cranking, stopping en trying again before firing up.
Also, the dashboard lights for handbrake and battery dimmed way down so I'm definitely replacing the battery today.
Won't know if it fixes everything for sure so I guess I have to see what it does tomorrow morning.

[FuST]

The new battery (maybe together with the new glow plug) seems to have solved the problem, cranking over much quicker now.
It's not starting as fast as when the engine is warm, but that is to be expected.

Problem solved, cheers!