Difficulty starting my TDI

[shogun2]

Golf Mk V TDI is now over three years old, but has been serviced as per the manufacturers recommendations since new. However, over the last month or so I have niticed a difficulty in starting. It has not failed to start, but it seems to take a lot longer than when it was new - probably have to turn over the engine for five seconds or so. It also coughs a bit when it's turning over.

The Multivan, which is the same age, and has done more Kms doesn't have this problem, and starts immediately.

I'm not sure how the starter system works, so have no idea what could be wrong. Anyone have any thoughts?

Cheers,

Rod

[h100vw]

In an older diesel motor I'd have said it was glowplugs but I am not sure if yours uses them.

I'd start with a VAG-COM scan and go from there. Happy to do that for you if you don't want to go straight to the dealers.

Gavin

[gldgti]

starting any diesel requires a good fast cranking speed - perhaps your battery is getting tired?

key to starting a diesel is that compression builds fast (fast cranking) so that cylinder temp can be reached (it WONT start unless the air is about 500C - hence requiring full compression)

thats all i can think of - i'm unsure about if new tdi's have glow plugs.

have you changed fuel?

[Transporter]

All 4-stroke diesel engines including the TDI have glow plugs, that orange light you see lit in instruments which goes off when engine starts is glow plug control light.

How ever if you drive mainly short trips you battery might be low on charge.
My T5 battery didn't last 2 years and was replaced under the warranty by dealer when my engine didn’t start one cold morning. For 2 weeks before it happened I've observed unusually long cranking before the engine started in the morning even it stalled on me during starting.

Check the battery voltage drop while cranking.
I recharge my battery every second week now with CTEK battery charger.
CTEK battery charger can be used while the battery is connected in vehicle and it charges to 99% of battery capacity unlike vehicle charging system which charges to only 80% of battery capacity.

If battery and glow plugs are good I would use VCDS (Vag-com) to check for any clues.
By the way what oil did you use in the engine?

[shogun2]

Thanks guys,

Will check battery tomorrow

[Transporter]

Thanks guys,

Will check battery tomorrow

Hi, Shogun2
Before you start connect digital voltmeter to the battery and check voltage before you turn the ignition "ON". You should see at least 12.5V there. During cranking the voltage should not go below 9.5Volts.
If you need help PM me.

Cheers
MM

[silvershadow]

You are all assuming the glow plugs are OK - if all the plugs have failed then there will be problems starting the car on anything other than warm to hot days. My diesel 4WD displayed exactly these symptons until the last working glow plug called it quits when it became almost impossible to start without some outside assistance using a sprayer to spray WD40 into the intake while cranking the engine. Commercial products using ether can also be used to help start the engine until the glow plugs can be replaced. After-market glow plugs should be available through Repco.

The glow plugs can be checked with a multimeter set to 0 - 10ohm resistance measurement - if there is no resistance indicated, the glow plug has failed. A working plug should have a resistance around 1/1.5 ohms

[Transporter]

You are all assuming the glow plugs are OK - if all the plugs have failed then there will be problems starting the car on anything other than warm to hot days. My diesel 4WD displayed exactly these symptons until the last working glow plug called it quits when it became almost impossible to start without some outside assistance using a sprayer to spray WD40 into the intake while cranking the engine. Commercial products using ether can also be used to help start the engine until the glow plugs can be replaced. After-market glow plugs should be available through Repco.

The glow plugs can be checked with a multimeter set to 0 - 10ohm resistance measurement - if there is no resistance indicated, the glow plug has failed. A working plug should have a resistance around 1/1.5 ohms

Gee, I don't like that idea of using the strating fluid for starting late model TDI.

[shogun2]

A battery recharge overnight seems to have done the trick. Now seeing 13.6v on the battery without the ignition on. haven't been able to check the cranking voltage, as I can't see the multimeter and turn the key at the same time.

[bluey]

Batteries are generally meant to last 18-24 months or so. 3 years is about it I think for that battery. If there is any suspicion of a battery problem (ie slightly slow starting), I just get a new one. Haven't had to think harder than that about starting electrics for 20 years. (Obviously if a new battery doesn't fix it, then would need to look further.) Gone are the old days of DC generators and coil regulators.

Last school holidays, had a battery die dead as a doornail with the car parked at the driveway of a resort. No previous hints of a problem. A pain to have to call the NRMA to bring a new one - never seen a dodgier mechanic at work with el cheapo tools.

(I thought glow plugs were unnecessary over 20degC.)