Chevy aveo '09 ( misfires and check engine light )

[hossam]

Hi

My brother has just bought used chevy aveo 2009 ( 67,000 mile ) , he made a complete test using " sun machine " and everything was fine except three things :

- Very very high HC PPM

- Very low firing kv

- Machine stated a problem in ignition


and now the check engine light turned on and car isn't running smooth anymore, there are misfires

do spark plugs need replacement ? i'm not an expert in cars but i have a little knowledge

Waiting for your help , thanks in advance

TEST SAMPLES :

 

[Burnerman]

This is more likely to be a fault in the coil pack (the item that provides the spark plugs with their high voltage).
Its a common fault with many petrol engines and I would recommend its replacement - together with a new set of sparking plugs.
The chances are, it would sort out the emissions issue too.
John

 

[hossam]

This is more likely to be a fault in the coil pack (the item that provides the spark plugs with their high voltage).
Its a common fault with many petrol engines and I would recommend its replacement - together with a new set of sparking plugs.
The chances are, it would sort out the emissions issue too.
John

and how much does the coil pack cost ?

 

[Burnerman]

For that car, I've absolutely no idea......if the coils are individual, a typical GB cost could be £25 each - for a 4 cylinder coil pack, between £50 and £100.
I didn't realise this car was actually on sale in the UK - Chevrolet aren't particularly common over here, and none have come my way.
John

 

[hossam]

No actually i'm from Egypt and my brother is working in saudi arabia right now , so it's not in the UK

i have two other questions please

Is there a difference between spark plug wires and coil pack or it's the same thing ?


What's the difference between Firing KV and Spark KV ? because i see the spark kv is good here !

 

[Burnerman]

If its a block coil pack, the thick wires, called high tension leads, connect the coil to the spark plugs. These wires are heavy because of the insulation required around them.
Individual coils actually sit on top of the plugs, and have no HT wires - only thin wires feed them.
The firing voltage is higher than the spark voltage because the voltage has to build up in order to jump the spark plug gap.
I must say, the readings there seem pretty constant!
John