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My car is taking its time to start on these cold mornings, about december time i thought the battery was getting old but it was tested and is apparently fine, there starter seems to struggle a tad more, but on an especially cold morning its talking more turns before it fires up, the glow plug light goes out after a second, but could it be the glow plugs?

The HDi doesn't really need glowy's until the temp is about minus 10 deg C. You'd certainly benefit from a new set but it's not really something anyone complains about on here and you risk the chance of snapping one in the head.

I'd be thinking more about:

Starter Motor lazy (or it's wiring corroded), voltage whilst cranking etc.
Fuel quality
Fuel leak
Crank sensor maybe?

The ecu needs to see 60RPM minimum for a few seconds before it'll inject any fuel, (which why HDi's never start instantly hot or cold).

If you think the starter's a bit slow, that's probably it. When we had a cold enough winter for the glow plug light to stay on a few years back, I just spun mine over without waiting and it started same as ever. At least one of the guys on the coupe forum has had a broken glow plug relay for several years and no trouble starting. Direct injection engines are easy to start, indirects, (XUD et al), won't want to know in cold weather unless the glow plugs are OK.

I would also check all battery, starter and earth leads. A bit of corrisiion will definitely have more of an adverse affect in cold weather.

To be able to test a battery effectively you need to load it with the current that the starter takes, I don't think a garage can do this. If you battery is more than 4 or 5 years old it likely needs replacing. As Doggy says the engine needs to turn fast enough to generate sufficient fuel pressure, if it doesn't its most likely to be either the battery or starter that's at fault. You can check the voltage across the battery with the starter engaged and compare it with a car that starts or just try another battery, if you can jump start it from another car that would indicate a failing battery.

Peter

PeterN wrote:To be able to test a battery effectively you need to load it with the current that the starter takes, I don't think a garage can do this. If you battery is more than 4 or 5 years old it likely needs replacing. As Doggy says the engine needs to turn fast enough to generate sufficient fuel pressure, if it doesn't its most likely to be either the battery or starter that's at fault. You can check the voltage across the battery with the starter engaged and compare it with a car that starts or just try another battery, if you can jump start it from another car that would indicate a failing battery.

Peter

Most garages will have a high rate discharge tester for checking batteries, unless they have changed over to the latest digital testers that don't do a high rate discharge test.
I keep a high rate discharge battery tester in my van.

I have one but I think it only draws about 100 amps. I think the best way to test is under starter load - if you know what the voltage is supposed to be.

I capacity test (aircraft) batteries at work and the standard procedure is to discharge the battery at Cx1 rate for 1 hour or till it hits the end point voltage (10v for a 12v or 20v for a 24v battery). So for a 12v 33ah battery you would discharge at 33amps for 60mins or till it hits 10v if it hits 10v at 51mins then it's at 85%of its rated capacity. 85% is the pass mark for our batteries if they fail a capacity test we carry out a conditioning charge which consists of a low current (1/10 of C) until you get to a specific voltage and maintain it for four hours. Then the battery is retested if it fails again it gets scrapped. Our learjets pull something in the region of 1000A during start and trying to test a battery at that sort of current would be impractical.
I should also point out constant current charging is dangerous if not carried out correctly with proper safety precautions observed and all our battery work is carried out in a dedicated workshop by trained professionals using battery specific manuals.

Quick test. Put a voltmeter on the battery, and crank the engine. Should read a minimum of 10.5v whilst starter is turning. Turn it for about 5 seconds. When you stop cranking, watch the battery recovery rate. It should be around 12.5V before cranking, and should recover to same. It will probably be quite quick to 12.0V and start to slow down as it nears the 12.5V mark.

Also worth getting someone else to crank the engine and see what, if anything, comes out of the exhaust. White smoke, which is actually atomized fuel, usually indicates glow plug probs, nothing would indicate pump not running, black smoke usually indicates injector probs. (Very common when Easy Start has been overly used, as it tends to blow pintles off injectors.)

As to glow plug light going out, I read somewhere that they run for 8 - 10 seconds after the light goes out. Whether this is just relevant to 2.1TD or includes HDIs, I don't know, but could be checked with a voltmeter across battery.

I replaced the battery in my '6 today, it wasn't past it by any means but on cold morning starts it cranked quite slowly, not surprising though as it was the original battery! Put a new Bosch S5 in and the cranking is so much quicker, well worth doing

OllieNZ wrote:Our learjets pull something in the region of 1000A during start and trying to test a battery at that sort of current would be impractical.

Lick the terminals?

Welly wrote:

OllieNZ wrote:Our learjets pull something in the region of 1000A during start and trying to test a battery at that sort of current would be impractical.

Lick the terminals?

You can give it a go if you want, I'll even stand there with a lump of 4X2 to pry you away from the battery once your hair gets good pointy.

Frank, is the Hdi a Siemens 90, I can't remember.

There was a discussion a while ago about the hand priming bulb becoming porous over time, allowing air into the fuel pipes overnight.

GingerMagic wrote:Frank, is the Hdi a Siemens 90, I can't remember.

There was a discussion a while ago about the hand priming bulb becoming porous over time, allowing air into the fuel pipes overnight.

I think the 90 came with both bosch and siemens fuel injection, mine is a 110 no sign of a hand priming bulb, but that porous issue might be why air bubbles appear in my mates 407 although the newer priming bulbs are made out of a really cheap crappy plastic, the old ones were quite good.