Cold start problems

[TimGti]

Our polo is really not liking the cold weather! The Mrs hasn't driven it for a week, so its sat out in the cold/snow, but its been struggling more and more to start when its real cold outside. Its not the battery (turns over fine), just really struggles to actually fire up. When it does, it coughs and splutters and then stalls! Once it eventually gets going and warms up she's ok.

Im thinking spark plugs? Havent been changed in ages I dont think?

What should I be checking/changing and in what order?

Cheers
Tim

PS Im gonna VAGCOM it tommorow and see what codes it throws up then I'll update this.

[alexperkins]

Check all the spark plugs in accordance to this visual check guide: http://behcw.blogspot.com/2010/11/visua ... plugs.html

It could also be the temperature sensor as this controls cold start fuelling and idling- i would vagcom it and see what you get.

[TimGti]

Thanks Alex. Is it wise to just get the OEM plugs from TPS and how much are they roughly if so? Amazingly never had to replace a set of plugs before! I'll check them out & VC it tomorrow.

[alexperkins]

I would recommend it - they are the best quality, and are often made by NGK. A set depending if you get TPS Club discount or not will be about £20 quid without discount and £15ish with

If you dont know when they were last changed, I would change them anyway as its preventative maintenance.

[TimGti]

Thinking about it we've done about 30k in the car without changing them, and the cars on 78k now. They may even be the originals I guess

[alexperkins]

30-40k is an average change - time to do it

[TimGti]

What size socket do I need to get the plugs out please? Will need to buy this too! Its a 1.4 MPI

[alexperkins]

It's a large spark plug tool. Halfords do them. I'd advise getting the new plugs and get the tool size to match just to be sure

[TimGti]

It's a large spark plug tool. Halfords do them. I'd advise getting the new plugs and get the tool size to match just to be sure

Clearly, Im trying to put off going outside in the cold & actually sorting it, by thinking of as many questions as possible whilst sat in the warm

Tried to start it this morning and it wont fire up at all now, just coughs for a second and dies. Bad times

FIngers crossed for new plugs

[alexperkins]

Thats interesting - have you vagcom'd it yet?

[TimGti]

Thats interesting - have you vagcom'd it yet?

Yes, 3 codes

16706 - Engine Speed Sensor (G28): No Signal - Ive replaced this sensor last week and the engine check light went out immediately without even resetting it with VAGCOM. Good stuff I thought.

However, there is 2 new codes logged:

16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected
Possible Causes

* Air Intake System leaking
* Fuel Supply faulty
* Injector(s) faulty
* Ignition Cable(s) and/or Spark Plug(s) faulty
* Ignition Coil(s) faulty
* Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
* Camshaft Position Sensor (G40) faulty


16688/P0304/000772 - Cylinder 4 Misfire Detected
Possible Causes

* Ignition system
* Fuel injectors
* Fuel pressure
* Running out of fuel
* EVAP canister purge valve
* Evaporative emission system
* Low compression
* Base engine problems
* Controle Module damaged

Any thoughts?

[alexperkins]

Replace all the spark plugs and take lead 4 off and give it a thorough inspection.

It may be no more than a dodgy plug, but the fault code listed can signify an issue with the HT lead - give the contacts a squirt with WD40 at each end on all the leads after you have replaced the plugs, then clear the VAGCOM error codes and try and start it

[TimGti]

After standing in the snow for an hour to point I cant feel my toes, I've replaced the plugs (did the air filters whilst the cover was off, these were filthy!).

Car fired upon the second attempt which is more than it was willing to do this morning. It ran a bit rough for 5 minutes, but once warmed a bit & after some gentle revving it idled as it should. I was too cold to go for a drive, but I'll see if it starts ok again later and maybe take it out & then Vagcom it again.

Didnt clean the leads, but I'll do this tommorow if the issue persists.

Not convinced the plugs are causing the issue yet, but need a bit more time to monitor it now Ive replaced them.

[TimGti]

old plugs

[alexperkins]

good lord. the electrodes have gone!

Definately time for a change!!!

Id also try running a few tanks of redex through as the sparks were so poor, it would have caused excess carbon deposits.