Hello fellow polo fans, I have a Polo 6n2 1.0 from the 2000 with a really long cold start problems. Sometimes I have to try 7 or 10 times for it to finally start. But the thing is that it ONLY happens when the engine is cold. If it's warm, it starts right up like new. I can also feel the acceleration hesitate (like there's a delay in acceleration that suddenly picks up fast) when I start to drive away and the engine is still cold. The car has had this problem since I bought it 4 years ago, but it used to be just around 2 or 3 attemps before it would start. Lately it's just become worse and intolerable.

 

I replaced the battery and the coolant temp sensor, but still no luck. The fuel filter is also fairly new (2 years with not a lot of driving) although it might be time to change it again. Also, Idk if this is relevant but someone did an EGR elmination on this car before I was the owner, the egr is still there connected but the place where the EGR valve connects to the exaust manifold was eliminated with concrete or something else really hard lol.
 

It also has a hose that's not the related to the EGR valve that was eliminated. I grabbed the image below from somewhere else in the forum, and the hose highlighted in blue is cut and has a screw plugged in to clog it, which is something some mechanic must have done intentionally. I think this hose connects to the main breather hose, but the problem is that my breather hose doesn't have the little thing where this throttle body hose is supposed to be plugged (they prob replaced the original breather hose with one that lacks it), so I guess someone decided to just cut it and "eliminate" this hose. Do you think this might be causing the cold start problem? I doubt it but just wanted to know what other problems could this cause?

I also have another questions: the throttle body is a bit dirty with what seems to be oil, I removed it and cleaned it without touching it with a butterfly valve cleaner but it didn't clean it that much even though I used the entire can. Anyway, this didn't make any difference when it comes to the cold start problems after cleaning it. The butterfly valve does have some finger prints and scratches on it, which tells me that someone touched that valve, and I don't know it they realigned it afterwards (I doubt it).

Finally, there's another thing I noticed about the throttle body but idk if it's normal: the butterfly valve seems like it doesn't move at all unless I rev it up to around 2krpm, which will open it almost completely in a second, there's no "slight, steady opening" as I rev up the engine slowly. It's like it either opens completely or doesn't move at all... is this normal?  I thought that's weird even though I tested this with the engine cold and idk if it makes any difference when warm. I could see how this is related to the jerky driving in low rpms when cold.

 

Sorry for the long post, I've been beating my head over this for the past month and I just need some help.

Welcome to the Forum.

 

Whilst attending to the EGR and the hoses might make some improvements, it seems to me that, as the problem only occurs when the engine is COLD, then we should be looking elsewhere.

 

My first port of call would be in checking for condensation on the spark plugs, or more likely on the coil packs.

I would suggest that, before you attempt a start on a dry cold day, check and dry if necessary the above items - You could use a hair drier to make sure that every trace of moisture is removed.

 

When checking the coil pack, look out for what might look like pencil lines on the insulation. If there are any, they will be caused by high tension 'tracking' which then can become conductive.

The only real cure is replacement, but you may obtain some temporary cure by applying some solid wax polish (shoe polish will do) to the affected area.

 

As for the petrol filter, a partially blocked one would probably manifest itself under full load, rather than at cranking speed.

 

Have a look at the above items, and let us know if the problem is still there.

 

Regards.

 

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