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Greg
Greg, Technician
Category: Car
Satisfied Customers: 7127
Experience:  Automotive diagnostic tech
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I recently purchased a polo 1.2, 12V, 2004, 65K, and have had the timing chain, guide

Resolved Question:

Hi,
I recently purchased a polo 1.2, 12V, 2004, 65K, and have had the timing chain, guides and tensioners replaced, which has slightly improved the clattery noise of the engine, but it still sounds like a diesel when starting. I understand that these 3 cyl. engines are not the smoothest or quietest normally. I had also hoped that there might be an improvement in cold starting but it still remains a problem. Occasionally engine cold-starts okay, sometimes tries to fire but fails to catch and sometimes engine cranks over without any cylinder firing. When it doesn't start first time second turn of the key invariably starts engine. Engine warm-starts without a problem, runs well (although rather noisily),idles at constant 900rpm, and power and mpg are as expected. Battery is fully charged and new spark plugs and oil changed recently. I could probably live with the problem but the car is for my daughter who will need it for work and I'm concerned about the problem getting worse during wint
Submitted: 2 years ago.
Category: Car
Expert:  Greg replied 2 years ago.
Hi . Is the check engine light ON when the engine is running . Was the management system ever checked for malfunction codes . Greg
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Customer: replied 2 years ago.

No error lights on when engine running.

Management system was checked by my local service garage (not VW dealer) and they didn't specify the actual error code but said that there was an error with system " finding camshaft timing" which indicated timing chain wear. The timing chain hadn't jumped any cogs but the guides and tensioner were badly worn and therefore replaced.

Expert:  Greg replied 2 years ago.
Okay thank you .Now after the repairs is the check engine light Now off when the engine is running . Greg
Customer: replied 2 years ago.

Check engine light OFF when engine running before and after timing chain replacement.

I initially thought that poor starting might be linked to timing chain wear, but now wonder whether the poor starting is a separate problem.

Expert:  Greg replied 2 years ago.
Do you know if you have a malfunction code or not .

As normally a code will set if anything is wrong and light up the check engine light .
Now if you did have error codes found by the garage and the check engine light was not ON then there we have a problem .

These engine are known for bad starting when they have a malfunctioning coolant temp sensor .

But if no malfunction codes then the crank sensor could be your problem as this in Some cases will not trip a code .

What i suggest you do is leave the car with the garage so they can check the sensors in the morning on there scan tool .like if they have no engine speed readings this will point to a bad crank sensor .

Stuart , hard to say with me not being there but these are the most common issue
on this engine for a hard cold start .

Another cause is a timing chain tensioner failure will cause a hard start ,but we can rule this out if this was ALSO change when they did the chain??

If the engine still rattles after fitting the two parts you mentioned then have the chain replaced .

Rgds Greg
Customer: replied 2 years ago.

Thanks Greg,

No error lights on dash before taking car to service garage nor after having chain, guides and tensioner replaced. The plug in diagnostics test they performed indicated a problem that pointed to chain tension problem - the chain, chain guides and tensioner were all found to be badly worn and were replaced, but I don't know the actual error code.

Unfortunately the car is now with my daughter, 200 miles away, so if problem gets any worse she'll have to take it to another garage.

Regards Stuart.