[sans33]

After driving 5000 kms,I have become quite addicted to the feeling of power and torque,my S10 provides.But lately,after a 750 km trip by a guest, I noticed complete absence of that special feeling of power at wheels.I took the car to nearest dealer but they couldn't understand.They have cleaned air filter and changed spark plugs,but it has made little change.
Another thing I noticed is that while 3 plugs were clean,4th was completely black.Does it indicate some problem with injecter ?

[TURBOSAM]

am really sorry . as 1.6 engine failure is extremly rare even after 1,00,000 kms as long as the coolent and oil is changed regurlarly.
lets come to your problem
if 4 th plug was black then there are three possibilities
1>if the plug is oily black then either rings are down,valve guide oil seal is problematic or simply the head is loosing the sealing in that region
2>if the plug is dry black then the injector may be the culprit,, its either dripping or injecting continously <earthing the 4 th injector earth lead>it will severly leanout the other three cylinders! as the collective exhaust is checked by lambda sensor..
remove the plugs again . check the plugs again if the same cylinder is fouling the plug , get the injectors checked as well as the injector sub harness-possible mice attack
3>possibility of weak spark in that cylinder < 10.5 compression ratio means @ 10 times atmospheric pressure means 10 times the density of charge> and the spark may be jumping in open but cant INSIDE THE CYLINDER AT THE COMPRESSION STROKE .
change the plug cord with the paired cylinder .it will reveal the fact.
all the best
p m me if u need further help
all the best

Originally Posted by sans33

After driving 5000 kms,I have become quite addicted to the feeling of power and torque,my S10 provides.But lately,after a 750 km trip by a guest, I noticed complete absence of that special feeling of power at wheels.I took the car to nearest dealer but they couldn't understand.They have cleaned air filter and changed spark plugs,but it has made little change.
Another thing I noticed is that while 3 plugs were clean,4th was completely black.Does it indicate some problem with injecter ?

[vipul_singh]

Please check the coolant temperature as well, while you are at it. I have noticed the 1.6 engine cuts back a little if it gets really hot. Could that be part of the problem, apart from the plug fouling, that is?

[sans33]

Originally Posted by TURBOSAM

am really sorry . as 1.6 engine failure is extremly rare even after 1,00,000 kms as long as the coolent and oil is changed regurlarly.
lets come to your problem
if 4 th plug was black then there are three possibilities
1>if the plug is oily black then either rings are down,valve guide oil seal is problematic or simply the head is loosing the sealing in that region
2>if the plug is dry black then the injector may be the culprit,, its either dripping or injecting continously <earthing the 4 th injector earth lead>it will severly leanout the other three cylinders! as the collective exhaust is checked by lambda sensor..
remove the plugs again . check the plugs again if the same cylinder is fouling the plug , get the injectors checked as well as the injector sub harness-possible mice attack
3>possibility of weak spark in that cylinder < 10.5 compression ratio means @ 10 times atmospheric pressure means 10 times the density of charge> and the spark may be jumping in open but cant INSIDE THE CYLINDER AT THE COMPRESSION STROKE .
change the plug cord with the paired cylinder .it will reveal the fact.
all the best
p m me if u need further help
all the best

Thanks SAM for such detailed information.I wish you were here.Guys at Him motors changed the plugs telling me that it is fitted with twin tip ones instead of single tip plugs.They never told me about fouled plug;and when I asked them,they told me not to worry as they have changed them.
I havn't rechecked plugs till now,as I was out of town.I will get these checked at some local mechanic .