VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold

Honest John Back Room » Technical matters
View Threaded
Fri 23 Aug 2013 15:04
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - RueyBristolVW

Hi everyone, I'm new to the forum, checked a few out and thought the advise offered on this one seemed very good so over to you ....

Ref my car, it’s a Golf 2.0 GT TDI (140) on a 2004 plate – it’s a mk5 version.

The problem, it starts absolutely fine cold, first time. When the engines warm, it doesn’t start very easily, in fact it turns over for a few seconds before it eventually starts, almost like it’s stalled or the batteries flat.

There’s various views and opinions surrounding this, which are available on the internet. A number of views on the internet point to glow plugs as a possibility. My garage chap, ran diagnostics on the car and it returned a fault with ‘Glow Plugs’. Although they’re not 100% certain, it’s looking possible that the glow plugs are what’s causing the starting problem.

Also, I’ve been told that when replacing glow plugs they can snap and if this happens then I’ve a bigger problem to replace them, engine out. Normally and in most cases the glow plugs come out easily without snapping and are replaced. However, this is still causing me concern, especially considering it’s not necessarily going to fix the problem.

Another garage who are mapping specialists have suggested a PD 'hot start' Map, which will apparently solve the problem, this garage (the mapping specialist) has said that he's repaired this problem on multiple occasions and it will work. I'm worried because I've been told mapping can just add to problems.

So over to you lot - talk to me, help me!!?? Look forward to hearing from you and thanks in advance for your time.

Reply | Report as offensive | Link
Fri 23 Aug 2013 16:27
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - 659FBE

If it starts cold, the problem is not the glowplugs. A hot engine does not need them at all for starting, although they are energised post-start to reduce smoke.

Observe carefully the glowplug light on the panel and check that it illuminates (briefly) when you request a hot start. If not, there is probably solder fatigue in the 209 relay next to the engine ECU. Other causes can be leaky injector "O" rings or a leaky (internlly) tandem pump which will cause loss of priming pressure. Occasionally a leaky fuel filter "T" piece and its two "O" ring seals will cause this fault. Hot fuel is less viscous than cold.

Finally, and preferably following a proper diagnostic check using VAG compatible (not unspecified generic) software, take a very careful look at the camshaft position sensor. These engines will start and run normally without this item, but it takes a lot of cranking for the ECU to assign fuel to the correct cylinders using the crank position sensor alone. Sometimes the cam position sensors fail when hot - they're at the top of the engine under the padded lid, so they get very hot on soak-back.

With the emphasis on VAG compatible software, a diagnostic check will be the quickest route to a fix.

659.

Reply | Report as offensive | Link
Fri 23 Aug 2013 16:39
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - RueyBristolVW

Thanks for the advise, I'll look into it ... I love VW's but mainly had petrols and campers, this is my first GT TDi so a lot of your advise has just sailed over my head ... but it's massively appreciated, I've printed it off and will take it to my mate at the garage ... May I ask: are you advising against a PD Hot Start Map ? Also, is there software out there that people will use and it's not VAG compatible? Surely, it just wouldn't work ... would you mind explaining a little more?

Thanks in advance for your time ...

Reply | Report as offensive | Link
Fri 23 Aug 2013 16:53
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - 659FBE

Don't interfere in any way with the engine map. A properly set up PD engine has no problems with hot starting or any other aspect of its operation. It sounds as though your garage may have a non customer-oriented agenda here, and I would advise extreme caution.

If they can't easily fix a PD with poor hot starting, they should not be fiddling with re-maps.

Finally, although uncommon, a worn fuel lift pump in the tank can cause this problem with a hot engine. The return fuel on a PD engine is very hot indeed and heats the pump.A pressure check will nail this.

As a test, you could try filling the tank brim full - the bulk fuel in the tank will then keep the pump cool. I never usually run my PD below 1/2 full unless on a long run. This lengthens the life of the lift pump considerably by cooling it.

659.

Edited by 659FBE on 23/08/2013 at 16:54

Reply | Report as offensive | Link
Fri 23 Aug 2013 17:10
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - RueyBristolVW

Thanks for your advice, great advice on full tank test, on my way to fuel station to fill up !! I didn't like the idea or sound of a PD Hot Start Map anyway!! ... Cheers

Edited by RueyBristolVW on 23/08/2013 at 17:17

Reply | Report as offensive | Link
Sat 24 Aug 2013 18:53
VW Gold 140 TDI 2004 Plate - Golf 140 TDI warm start problem - starts fine cold - Micky-BO

Two of the most very common faults for this warm hard starting is top dead centre going open circuit when warm but when cools becomes ok. 2nd most likely is starter motor if faulty ok when cold but when warm draws too much current depriving the injectors of power Hth Regards Mickeybo

Reply | Report as offensive | Link

We give you the low down on how to save on insurance, little-known tricks and tips, what insurance groups mean and how to use insurance aggregators to beat insurers.

Insurance group finder and how to save on insurance